COLD ROLLING MILLS and STRIP PROCESSING

Transcription

SMS metallurgy Conference 2007
Session 3
COLD ROLLING MILLS and
STRIP PROCESSING LINES
Most recent technologies in
cold rolling to improve product
quality
Dipl.-Ing. Rüdiger Holz
Execute Vice President
Cold Rolling Mills Division
Dr. Hartmut Pawelski
General Manager
Metal Forming and Surface Technology
Dr. Karl Hoen
General Manager Plant Technology
Hot/Cold Rolling Mills Division
Dipl.-Ing. Christoph Schwarz
Deputy General Manager
Technical Sales Cold Rolling Mills
SMS Demag AG
Düsseldorf/Hilchenbach, Germany
Most recent technologies in cold rolling to improve product quality
Rüdiger Holz, Dr. Karl Hoen, Dr. Hartmut Pawelski, Christoph Schwarz
In recent years, the steel industry worldwide achieved remarkable growth rates.
It is not only growing in Asia, here especially in China and India, but also in
Europe and America. At the same time,
its consolidation is going on and the
steel markets become more and more
global.
In such an environment it is important for
mill owners to meet highest quality requirements and at the same time curb
the production costs.
SMS Demag as system supplier for integrated solutions of rolling mill technology
developed a large number of suitable
systems for supporting mill owners in
these efforts. Examples of effective solutions in cold rolling mills for achieving
high quality requirements and highest
economic efficiency are the following:
▬ Equipment for Edge Drop Control to
achieve a constant strip thickness
across the complete width,
▬ the T-roll® process technology,
▬ an alternative lubrication and cleaning concept for an improved strip surface quality and
▬ online measuring systems for the
documentation of product quality and
meeting of narrower tolerances.
Edge Drop Control (EDC®)
Edge Drop describes the undesired
thickness drop in the edge zone of cold
rolled strips. Reason for it is the changing roll flattening in the transition from
the loaded to the unloaded rolling section. Depending on the intended use of
the strip, this area has to be removed.
For this purpose, the strip is trimmed
what will reduce the plant yield.
For avoiding such losses, SMS Demag
developed Edge Drop Control strategies
for reversing cold mills and tandem cold
mills.
For compensating the thickness drop,
the work roll diameter in the strip edge
area has to be reduced. For this purpose, the work roll barrel is tapered by a
special grind at one end. The principle of
the control is now based on shifting the
taper for so far into the strip edge zone
until a specified edge drop value is set.
The operating results of the CSC reversing mill in Taiwan illustrate the difference
between using and not using an Edge
Drop Control for non-grain-oriented
silicon steel. Application of the Edge
Drop Control was able to reduce the
trimming losses by over 20 mm for each
side. This increases the yield for the
common strip width by more than 3 %.
The strategy for a continuously operating
tandem mill is a combination of openand closed-loop controls. The drop in
thickness is measured after the first and
the last stand (stand 5). The first measurement is used for controlling the edge
drop in stand 1. At the same time, this
signal is applied for a pilot control of mill
stands 2, 3 and 4. The measurement
after the last stand is introduced to correct the control command of the pilot
control in mill stands 2, 3 and 4 and that
way the desired edge drop value after
stand 5 is set.
As the operating results show, this strategy is suitable to set a constantly low
value for edge drop over the entire strip
length and thus subsequent trimming
losses are reduced.
®
T-roll process technology
For optimizing the cold rolling process
and for an improved product quality it is
indispensable to understand the physical
processes during cold rolling in a better
way.
Therefore SMS Demag developed
T-roll®, a technology package including
new and enhanced physical model approaches for simulating the cold rolling
process. Beside the complete mechanical and thermal description it is above all
the detailed and realistic description of
the tribological processes which open up
new options for process optimization.
The accuracy of the model approaches
becomes apparent in the high coincidence between measurement and simulation. Examples are the accurate simulation of rolling force and strip lead as
well as the transfer of the roll surface
roughness onto the strip surface.
As examples for the efficiency of T-roll®,
the optimization of a single-stand reversing mill for the production of grain-oriented silicon steel shall be mentioned. In
this project, the lubricant and the application of lubricant could be improved in a
well-aimed way by the new way of considering the tribology in the roll gap. This
enabled a clearly higher rolling speed
and thus a clear improvement of the
plant's output capacity.
A second example is the avoiding of
form waves in cold rolling of brass in a
two-stand tandem mill. It was only
through the analysis of the problem by
means of the T-roll® technological package and a test setup in the laboratory
based thereon that it was demonstrated
that the form waves exclusively occur
through insufficient lubrication conditions. By improving the lubricant and direct application of an additive in the first
passes the form waves were avoided.
Lubrication and cleaning concept
As a new lubrication and cleaning concept, SMS Demag developed a combination of least quantity lubrication and
the utilization of liquid nitrogen. In skinpassing, this concept decisively improves the strip surfaces and at the
same time curbs the operating costs.
When using the least quantity lubrication
in the skin-pass stand entry, the lubricant
volume is precisely applied, which is required for reducing the friction in the roll
gap. This reduces the rolling force and
improves flatness at simultaneously using a minimum quantity of lubricant. The
liquid nitrogen in the exit covers both the
strip surface and the roll surface. This
method has the following advantages:
▬ clean and dry strip surfaces and thus
clearly lower susceptibility to rust,
▬ clearly reduced efforts in the downstream cleaning steps for cleaning
the strip surface and
▬ prolonged work roll service lives.
For assessment of the strip surface quality, the same material was skin-passed
under different operating conditions. In
the pass with emulsion, clear impressions of the lubricant could be found.
They make the surfaces appear less
bright. The roll abrasion in dry skin-passing has a similar effect on the surface
quality. Compared to that, the surfaces
are clearly more uniform and thus
brighter when using liquid nitrogen in the
entry or in the entry and exit.
Moreover the operating experience
showed that the use of nitrogen more
than doubled the work roll service lives.
This and the lower refinishing effort on
the strips led at our cooperation partner
C. D. Wälzholz to cutting the process
costs for skin-passing by ca. 20 %.
The most recent reference for this concept is the new inline skin-pass mill
stand for the continuous annealing line
of ThyssenKrupp Steel in Dortmund,
Germany.
Online measuring systems
Efficient production on a high quality level today requires complete documentation of the main quality parameters. Only
that way it is possible to demonstrate
quality towards the customer and at the
same time efficiently track down causes
for quality problems in the process line
and to remedy them.
Our new "Rotary Inspect" inline inspection line sets the record here for safety
and ergonomics in the manual assessment of strip top and bottom sides.
Our patented roughness control system
enables controlling the strip roughness
over the entire length to a constant value
and to perform the roll change only when
it is really needed. For roughness measurement, the SORM 3 plus measuring
system of our cooperation partner EMG
is used.
The SMS Demag flatness measuring
roll is the ideal solution for precise and
reliable measurement of strip flatness.
The closed surface of the roll avoids
marks on the strip and can be coated
specifically for each application. The roll
allows simple installation of the sensors which can even be performed on
site. The sensors can be arranged flexibly regarding their distances in accordance with the current and future requirements of the profile and flatness
control system.
Ten references within a short time
demonstrate our customers' high
acceptance of this measuring system.
Most recent technologies in cold rolling
SMS Demag solutions for improved product quality
Edge Drop
Control
EDC
T-roll®
process technology
Constant strip thickness
up to the edge
Higher yield and improved
product quality
Lubrication and
cleaning concepts
Online measurement
systems
A new approach for
perfect surface quality
Closer tolerances and
better documentation
T-roll® process
technology
Lubrication
and cleaning
concepts
Online measurement systems
1
EDC® Edge Drop Control constant strip thickness
up to the edge
Edge Drop
Control
T-roll® process
technology
Lubrication
and cleaning
concepts
2
Principle of the Edge Drop Control
Principle of work
roll shifting for
Edge Drop Control
Edge Drop
Control
Influence of EDC on the
strip edge
T-roll® process
technology
Lubrication
and cleaning
concepts
Reduced
Edge Drop
Strip thickness
with EDC
without EDC
transverse
material flow
Strip width
3
Results of Edge Drop Control in a single-stand
reversing mill
Edge Drop measurement
Edge Drop
Control
Thickness deviation [%]
0.5
T-roll® process
technology
Lubrication
and cleaning
concepts
After last pass
0
with EDC
-0.5
Hot strip
-1
-1.5
without EDC
-2
-2.5
0
20
40
60
80
100
Distance from strip edge
Material: Non grain-oriented silicon steel
►
►Yield increased by approx. 3 % due to by reduced trimming losses
4
120
Edge Drop Control strategy for a continuous
tandem cold mill
EDC feed forward control and feedback control of S2, S3, S4
EDC feedback control for S1
Edge Drop
Control
S1
S2
S3
S4
S5
T-roll® process
technology
Lubrication
and cleaning
concepts
WR
AW
shifting
Position
WR
AW
shifting
Position
Ref
Act
Ref
WR
AW
shifting
Position
WR
AW
shifting
Position
Ref
Ref
measured
edge drop
AddRef
AddRef
EDC
EDC
feed
Vorsteuerung
forward control
EDC
feedback
control
EDC
Regelung
G1
EDC
feedback
control
EDC
Regelung
edge drop
references
AddRef
G2;G3;G4
Model
parameter
5
Results of closed loop Edge Drop Control in a
tandem cold mill
with EDC
T-roll® process
technology
EDC
workroll shifting position
EDC-Position (measured)
100
position (mm)
Edge Drop
Control
Lubrication
and cleaning
concepts
80
60
40
20
0
0
100
200
300
400
500
600
700
800
900
1000 1100 1200
Strip length [m]
Strip
length [m]
G2
G1
G4
G3
Edge
measured
Edgedrop
drop (measured)
EdgeEdge
drop
drop(μm)
[μm]
80
Reference value:
after stand 1 20 μm
after stand 5 10 μm
60
40
20
0
-10
0
100
200
after G1
300
400
after G5
500
600
700
800
900
1000 1100 1200
Strip length [m]
►
►Edge drop reduction constant over total strip length
6
measured
edge drop
T-roll® process technology
Edge Drop
Control
T-roll®
process
technology
Lubrication
and cleaning
concepts
Technology package for the simulation of the cold rolling
processes with advanced models for
▬ mechanical
▬ thermal and
▬ tribological processes
Applications:
▬ thermal and tribological processes
▬ Analysis and optimization of
lubrication and cooling conditions
▬ Selection of adequate lubricants
▬ Development of new rolling strategies
▬ Calculation of pass schedules for
new steel grades
▬ Pre-calculation of strip surface
roughness
►
►More profit due to higher yield and improved product quality
7
T-roll® process technology
Roll
Walzkraft
force [MN]
[MN]
Tribologisches
Tribological
modelModell
T-roll® process
technology
Lubrication
and cleaning
concepts
Roll speed
[m/min]
Walzgeschwindigkeit
[m/min]
Speed
Rolling
[m/min]
Voreilung
[%]
forward
Voreilung
slip[%]
[%]
Roughing of strip, Ra in μm
High capability of new approaches
Edge Drop
Control
3
2.5
2
1.5
Measured, top
Measured, bottom
1
Tribological model
0.5
0
0.0
0.5
1.0
1.5
2.0
Elongation in %
▬ High forecast accuracy for
improved processing and
Tribological
Tribologisches
modelmodel
Modell
tribological
Tribologisches Modell
Walzgeschwindigkeit
Roll speed
[m/min]
[m/min]
Walzgeschwindigkeit
[m/min]
Rolling
Speed
[m/min]
8
higher plant utilization
2.5
Cold rolling of high-grain-oriented silicon steel
5 pass HGO
Share of production approx. 30 %
Edge Drop
Control
Max.rolling speed
[m/min]
900
T-roll®
process
technology
Lubrication
and cleaning
concepts
600
300
0
pass 1
pass 2
pass 3
pass 4
900 m/min = max. motor speed
pass 5
before modernization
after modernization
►
►Increase of maximum speed by tribological optimization
9
Cold rolling of brass on a tandem cold mill:
elimination of waves
Edge Drop
Control
T-roll® process
technology
Lubrication
and cleaning
concepts
►
► SMS Demag solutions:
▬ Optimization of lubricant
▬ Low quantity lubrication for first passes
10
Combination of low-quantity lubrication and
liquid nitrogen
Edge Drop
Control
T-roll® process
technology
Lubrication
and cleaning
concepts
Low quantity lubrication
Liquid nitrogen
In cooperation with:
C.D. Wälzholz
►
► Benefits:
▬ Substantial reduction of
lubrication quantities
▬ Improvement of strip surface quality
▬ Reduction of friction in the
roll gap
lower rolling force
improved strip flatness
▬ Longer service life of work rolls
▬ Better cleaning effect on work rolls
11
Skin-pass rolling with liquid nitrogen
Valuation of strip surface quality after skin-pass rolling
Target: Ra = 1,0 1,8 μm; shining surface
Edge Drop
Control
Emulsion, entry
(height profile: ± 0,8 μm)
T-roll® process
technology
dry
Liquid nitrogen,
entry
100 μm
Lubrication
and cleaning
concepts
lubricant impressed
Abrasion of rolls
Improved surface quality
►
►Considerably improved strip surface quality
12
Liquid nitrogen,
entry and exit
Skin-pass rolling with liquid nitrogen
Dry (2004-05-03)
3.0
Edge Drop
Control
T-roll® process
technology
Roughness of new work roll: 3 3.3 μm
2.5
2.0
1.5
1.0
0.5
0.0
1
Lubrication
and cleaning
concepts
2
3
Coil No.
4
after coil No. 1: 1.4 μm
after coil No. 4: < 1.0 μm
5
Liquid nitrogen (exit)
Roughness of new work roll: 3 3.3 μm
3.0
3.0
2.5
2.0
1.5
1.0
0.5
0.0
1
2
3
4
5
6
7
8
9
10
10
Coil No.
►
►Service life of work rolls increased by more than 100 %
Skin-pass process costs reduced by 20 %
13
Recent reference:
ThyssenKrupp Steel, Germany
New inline skin-pass mill for continuous annealing line
Edge Drop
Control
T-roll® process
technology
Lubrication
and cleaning
concepts
Main technical data:
Strip thickness:
Strip width::
Roll speed range:
Annual capacity:
Year of commissioning:
Inline-skin pass
0.4 to 2.3 mm
600 to 1,720 mm
0 to 412 m/min
780,000 t
2007
Technical features:
▬ Newly developed low-quantity lubrication
system and roll-strip cleaning with liquid nitrogen
▬ SMS Demag shapemeter roll
▬ X-Pact® electric and automation systems
14
Online measurement systems to improve product quality
and plant utilization
Edge Drop
Control
SORM roughness
measurement
with control system
T-roll® process
technology
Inline inspection line
Rotary-Inspect
Lubrication
and cleaning
concepts
SMS Demag flatness measurement roll
In cooperation with:
►
► Advantages:
▬ Continuous monitoring and documentation of quality parameters
▬ Close tolerances by means of integration in closed loops
15
SMS Demag flatness measuring roll in new design
References in 18 months:
7 plants with a total of 10
shapemeter rolls
Edge Drop
Control
T-roll® process
technology
Lubrication
and cleaning
concepts
►
► Advantages:
▬
▬
▬
▬
▬
Easy sensor installation even at site
Applicable at high temperatures e.g. production of Si-steel grades
Individual arrangement of sensors
Closed surface
Application-based coating
16
Modernization concept of the
four-stand tandem cold rolling mill,
BILSTEIN GmbH & Co. KG
Dipl.-Ing. Detlef Böttner
Sales Cold Rolling Mills Electrical and Automation Systems
Dipl.-Ing. Falk Töpfer
General Manager
Dipl.-Ing. Arnulf Wurm
Senior Project Manager
SMS Demag AG
Hilchenbach, Germany
Modernization concept of the four stand tandem cold mill,
BILSTEIN GmbH & Co. KG
Detlef Böttner, Falk Töpfer, Arnulf Wurm
Ever increasing requirements on the cold
strip qualities and the continuously growing material and variant diversity more
and more force rolling mill owners to
keep their plants on the most recent
technological level or to get them there.
Due to the concurrently very high demand volume and thus the plant utilization in recent years, they had to face
particular challenges.
SMS Demag took up these customer
problems and elaborated and constantly
developed special concepts in recent
years to cope with them. This is one of
the reasons why the company BILSTEIN
with their registered office in Hagen,
Germany, tasked SMS Demag with the
extensive modernization of their fourstand tandem cold mill.
BILSTEIN is processing a diversified material and product mix starting from the
standard grades over case-hardening
and special grades up to micro-alloyed
high-strength steels. The tandem mill is
the central key plant for the complete
production at BILSTEIN and in some
cases also for their subsidiary companies. Therefore a consistent and reliable modernization concept was even
more significant for taking the decision to
award the contract.
The rolling mill was supplied in 1969 by
SMS Demag and was during the years
upgraded and modernized several times.
This mill produces every year 400,000 t
of cold strip of width from 320 to 670 mm
and thicknesses from 7.5 to 0.3 mm. The
input stock is produced by slitting hot
strip normally into two to three stripes.
Therefore the input stock has different
wedge profiles what is a particular challenge for the sequences in cold rolling.
The modernization is related to a large
number of objectives of which the following are the most important ones:
▬ Improvement of the plant availability
▬ Increase of the production volume by
60,000 t/year
▬ Improvement of the product quality
▬ Increase of the degree of automation
A particular requirement which made the
matter more complicated is that due to
the above mentioned plant utilization the
proper revamp times could only be taken
during regular shutdowns. The total time
available for this is three shutdown periods of altogether five weeks. After each
modification period, production has to be
run up to the set point volume according
to agreed run-up curves as fast as possible. In the process, the comprehensive
product mix of wedge-shaped hot strip
has to be considered and the currently
applicable safety standards have to be
observed.
For various reasons, SMS Demag won
the contract for this modernization.
SMS Demag has wide experience in
large and complex modernizations and
was also in this case able to present a
coherent overall concept. The "All from a
single source" supply, i. e. the symbiosis
of mechanics, hydraulics, electrics and
automation as well as development and
technology from one single supplier creates the optimal conditions for modernization which were critical in terms of
technology and time. Essential mechanical components as e. g. the hydraulic
adjustment cylinders and valve stands
are produced in the SMS Demag workshop and carefully tested before delivery. Moreover, the extensive actions accompanying the order are performed for
safeguarding the short modification
phases. Among these are careful site investigation, early setup of a "listening
mode", a state-of-the-art integration test,
the early operator training on the simulated plant up to a sophisticated changeover concept between the old and the
new control system.
For achieving the modernization objectives, many components are replaced by
new and more recent ones or additionally integrated into the rolling mill.
For increasing and stabilizing the strip
back tension in the first stand, an additional strip pinch roll unit will be installed
in the entry guide. It is hydraulically
approached, the additional strip tension
is applied by means of electrically actuated rolls. That way it operates similar to
a bridle roll unit but compared to that it
bears the advantage that it can still be
used for large entry thicknesses.
All mill stands will be equipped with hydraulic adjustment cylinders. That way it
is not only possible to increase the rolling force by 30 % in each mill stand but
for the first time it is possible to measure
the precise positions of the cylinders.
This is the prerequisite for converting the
strip thickness control from the currently
used roll gap control to a quick volume
flow control.
Moreover, the rolling speeds of all mill
stands are increased and optimized with
regard to one another. For this purpose,
among other things new gearwheel sets
will be installed. For minimizing the remaining quantity of residual oil on the
strip, the patented SMS Demag Dry Strip
System (DSS) will be installed downstream of the last mill stand.
The coiling tension will in a similar way
as on the entry side be separated by a
new approachable bridle roll unit from
the exit tension of the last stand. When
the bottom roll of this unit is not approached, it behaves like a "normal" deflector roll, i. e. also this bridle roll unit
can, as the strip pinch roll unit on the
entry side, be started up step by step
without any risk. Various other mechani-
cal extensions supplement the modernization. Among these are in particular:
▬ Various improvements for guiding
and threading the strip
▬ Improvements for calibrating the roll
assemblies
▬ Installation of work roll bending systems at all stands
▬ New hydraulic valve stands for all
mill stand functions
▬ Installation of devices for measuring
strip position, strip tension and strip
speed at different positions.
cessed from all local stations, strip edge
detection and camera systems will be installed at different locations. The latter
are provided for visual monitoring of the
partly automated threading process by
the operator. This is particularly required
when threading the wedge-shape slit
strip.
The automation system will be completely replaced. In the process, all Level 1
functions from the sequence processes
up to the technological controls are all
implemented on a uniform hardware and
software platform.
The existing electrical and automation
systems will to a large degree be replaced by new systems. Interfaces are
created with the remaining components
and systems. All main drives will be replaced. For the mill stands, advanced
synchronous motors in medium voltage
technology will be used. Compared to
the asynchronous motors, they provide a
higher operating efficiency at a simultaneously smaller moment of inertia which
leads to improved control dynamics.
State-of-the-art multi-drive converters
with a direct current intermediate circuit
supply the medium-voltage motors of the
mill stands as well as the low-voltage
motors of the strip drives for the reels,
pinch roll units and bridle rolls. This reactive power-free drive constellation both
minimizes possible energy losses and
negative effects on the feeding network.
The plant will for the first time be operated from a newly erected main control
pulpit. Except new operator stations and
an HMI system which can also be ac-
In particular for safeguarding the increased requirements on the automation
system, faster coil sequence times and
an improvement of the strip quality at the
head-end, for the first time a Level 2 system will be used on this mill. Above the
required interfaces and various report
functions, this system makes available a
model-based setup value calculation before start of rolling. For this purpose,
SMS Demag uses the complete imaging
of the rolling processes through selfadapting physical models.
For safeguarding the required run-up
curves after the respective short modification phases, SMS Demag uses a concept of several parallel actions. First the
current status is detected by means of
detailed examinations and used as the
basis of the following modifications.
Among these are e. g. detection and
localization of the mechanical and electrical components, functional and pro-
cess-technological aspects as well as
the plant operation.
By documentation of this site investigation, the engineering could start. On site
almost simultaneously the preparation of
the interfaces is started for the systems
required in the individual modification
phases which are continued to be operated. Moreover, a "listening mode" is established. For this purpose, so-called
process IO servers are installed step by
step which enable forwarding each signal from or to the process to the existing
control (maintaining the existing status)
but also making available these signals
in a global memory for the later new control systems. That way the new system
has knowledge of the current process
events at a very early stage. This resulting process data basis will be integrated
in the engineering and the pre-commissioning of the new system. That way for
example the mathematical models can
already at that time automatically adapt
to the material to be rolled and the existing plant.
In a next step, the complete new automation system will be set up in the
SMS Demag workshop. In parallel, the
rolling mill will be simulated in every detail in real time. Here not only the rolling
process itself is simulated but also all
movements and all interfaces with the
automation system. By means of this
"integration test", already beforehand a
pre-commissioning, complete functional
and production tests are performed. This
comprehensive simulation is also used
for an intensive operator training. Only
that way it is possible to achieve the
short run-up phases.
Now the previously installed listening
mode is expanded in a modification
phase and the following optimization
phase to the effect that new functions or
controls can be added in, tested and optimized either completely or also partly.
For this purpose the old and the new
open- and closed-loop systems are operated in parallel. That way the original
condition can quickly be re-established
by digital adding-in. It is only after all
new functions were sufficiently verified
and optimized that the "old" components
will be dismantled and the final new enhanced condition is established.
This modernization concept provides
both the plant operator company
BILSTEIN and the contractor
SMS Demag with the sufficient safety for
a smooth sequence of the modification
as well as the certainty that the modification objectives are really achieved within
the defined time frame.
Modernization concept of the four-stand tandem cold mill
The customer and their products
BILSTEIN GmbH & Co. KG, Hagen-Hohenlimburg
employees: 600
dispatch volume: 400,000 t/year
Introduction
Modernization
objectives
Modernization
items
Modernization
concept
▬ cold-rolled steel strip
▬ cold-rolled steel sheet
▬ construction steel
▬ case hardening steel
▬ electrical steel
▬ spring steel
▬ special purpose steel
▬ enameling steel strip
1
Four-stand tandem cold rolling mill
of BILSTEIN GmbH & Co. KG, Germany
Main mill data
▬ four-stand batch tandem cold mill
▬ Supplier: DEMAG, 1969
Introduction
▬ Rolling speed: max. 745 m/min
▬ Rolling force: max 6,000 kN per stand
Modernization
objectives
Modernization
items
Modernization
concept
2
Four-stand tandem cold rolling mill
of BILSTEIN GmbH & Co. KG, Germany
Material data
▬ Strip width: 320 to 670 mm
▬ Strip thickness: 7.5 to 0.3 mm
Introduction
Modernization
objectives
Modernization
items
Modernization
concept
▬ Annual production : 420,000 t
Others
▬ Several modernizations over the years
▬ Four operators, all on site
▬ Low automation grade of mill sequences
3
Targets of the modernization
General targets
▬ Increase of mill availability
▬ Increase of production rate by 60,000 t/y
Introduction
▬ Improvement of product quality
▬ Higher degree of automation
Modernization
objectives
Modernization
items
Special requirements
▬ Rolling and threading of wedge-type strips
▬ Extensive product-mix
Modernization
concept
▬ Change to operating with only three operators
▬ Only the regular mill downtimes can be used (in total five weeks)
▬ High priority in safe and steep run-up after each modernization
step
4
Reasons for placing the order with SMS Demag
▬ Experiences with
comprehensive modernizations
▬ Convincing overall
modernization concept
Introduction
Modernization
objectives
▬ Supply from one single
source
Modernization
items
▬ Manufacture at SMS Demag
workshop
Modernization
concept
▬ Switch-over
concept
▬ Advanced integration test
▬ Operator training in advance
5
Modernization of mechanical equipment
Entry-side pinch roll unit
▬ improve the strip tension behavior
▬ increase the strip tension
Advantages
▬ independent of the strip thickness
▬ deflector roll mode possible
6
Hydraulic screw down cylinders for all stands
▬ rolling force increase from 6,000 kN to 8,000 kN
▬ high resolution position measurement
Advantages
▬ higher reduction
▬ change from roll gap to position control mode
7
New gear sets respect. shifting gear sets between the stands
▬ increase the rolling speeds; from 745 to 1,000 m/min at last stand
8
Dry Strip System after last stand
▬ increase the removal of the emulsion on the strip surface
Advantages
▬ reduced noise level
▬ best dryness of the strip surface
9
Exit-side swiveling bridle S-roll set
▬ improve the strip tension behavior
▬ increase the strip tension
Advantages
▬ deflector roll mode possible
10
Modernization of electrical equipment
New synchronous motors for mill stands and tension reel
▬ increase the rolling speed of each stand
Advantages
▬ high efficiency
Introduction
▬ low inertia, i. e. high dynamic behavior
Modernization
objectives
Modernization
items
Modernization
concept
11
New multi-drive converter systems
▬ IEGT converters for MV mill drives
▬ IGBT converters for LV drives
Advantages
Introduction
▬ low energy losses, low power feed-in
▬ high dynamic performance
Modernization
objectives
Modernization
items
Modernization
concept
12
Introduction
Modernization
objectives
Modernization
items
Modernization
concept
New pulpit, operator panels and HMI system
▬ full HMI access at all operator panels
▬ industrial TV system and strip-edge monitoring systems
13
G3
G2
G1
G0
Thickness
Control
Thickness
Control
Thickness
Control
Thickness
Control
HGC
HGC
HGC
HGC
Introduction
Modernization
objectives
Modernization
items
Tension
Control
Speed and
Torque Control
Tension
Control
Speed
Control
Tension
Control
Speed
Control
Tension
Control
Speed
Control
Speed
Control
Speed and
Torque Control
Decoupling Net
Modernization
concept
New Level 1 automation system
▬ additional measurement devices for strip speed and tension
▬ position
sensors Operator
of screw down
cylinders,
monitoring
New Pulpit,
Panels
and vibration
HMI-System
Advantages
full HMI access at all operator panels
▬ switch-over from roll gap control to position control
industrial
system
and strip
edge monitoring systems
▬ introducing
fastTV
volume
control
mode
▬ one uniform system platform
14
Flatness
model
Rolling force
model
Mill limits and
configuration
Material
model
Introduction
Temperature
model
Tribological
Model
Modernization
objectives
Modernization
items
Modernization
concept
High-accuracy Level-2 setup system
▬ physical-based models
▬ short-term and long-term self-adapting models
Advantages
▬ reduction of off-gages/off-flatness length
▬ fast learning behavior
▬ flexible adaptation to new materials
15
High accuracy of SMS Demag Level-2 process models
(Example: Single-stand reversing mill for silicon steel)
30
45
1,525
strips
25
Introduction
frequency [%]
35
frequency [%]
Modernization
objectives
1,514
strips
40
20
15
10
30
25
20
15
Modernization
items
10
5
5
Modernization
concept
0
0
-1,600 -1,200 -800 -400
0
400
800 1,200 1,600 2000
force deviation at head end
[relative, kN]
-8
-6
-4
-2
0
2
4
6
8
thickness deviation at head end
[%]
77 % within 0 % to + 3 %
16
10
Overall modernization concept:
Engineering, test and interfaces preparation in parallel
Site
investigation
Introduction
Stepwise
Modernization
objectives
Preparation of interfaces/
listening mode
Installation
Switchover
Modernization
items
Modernization
concept
Plug &
Work test
Engineering
time
17
Site investigations
Site
investigation
Stepwise
listening mode
Introduction
Engineering
Installation
Switchover
Plug &
Work test
Modernization
objectives
Modernization
items
▬ hardware and layout
piping, routing, locations, etc.
Modernization
concept
▬ functional technology
signals, interfaces, etc.
Site investigation
▬ process sequences and mill operation
standard operation procedure
▬ process technology
pass schedules, emulsions, etc.
18
Hot run tests and shadow mode
New
Old
Site
investigation
Stepwise
listening mode
Introduction
Installation
PPS /L3
Switchover
Plug &
Work test
Engineering
Process
models /L2
Process
Models /L2
Process
control /L1
Process
control /L1
Modernization
objectives
RIOs
Modernization
items
Modernization
concept
Switchover
Installation
PIOS
~
~
PIOS (Process IO Server) =
electronic terminals
M
~
▬ stepwise function and production test
with mechanic and media systems
▬ test of sequences, test of dynamic behavior
▬ always possible to switch back to old controls
(shadow mode)
21
Typical run-up curve for a modernization
with production increase
130
Introduction
Modernization
objectives
Modernization
items
Modernization
concept
Production per week [%]
120
Downtime
110
100
90
80
70
60
50
40
30
20
10
Weeks
22
39
37
35
33
31
29
27
25
23
21
19
17
15
13
9
11
7
5
3
1
0
Cold rolling of stainless steel
using continuous high-performance tandem mills
Dipl.-Ing. Ralf Matzka
General Manager
Technical Sales Cold Rolling Mills and
Stainless Steel Lines
Dipl.-Ing. Rainer Effertz
Filtration Systems/Roll Coolant Systems
Dipl.-Ing. Thorsten Bode
Manager
Metal Forming Technology
Dipl.-Ing. Rüdiger Holz
Executive Vice President
SMS Demag AG
Düsseldorf/Hilchenbach, Germany
Cold rolling of stainless steel using continuous high-performance
tandem mills
Ralf Matzka, Thorsten Bode, Rainer Effertz, Rüdiger Holz
The market for cold-rolled stainless steel
strip is characterized by continuous
growth. The ever higher growth rates of
cold rolled products require ever higher
capacities of the process lines and
rolling mills. Further the market requires
reasonable prices for these products,
with the optimization potential mainly being the cost of production.
As long ago as 1969, the Nisshin Steel
company in Japan attempted to satisfy
this market requirement by installing a
then highly productive multi-stand tandem mill for the production of cold-rolled
stainless steel. Another high-performance mill, supplied by SMS Demag,
went in operation in 1999 at AK Steel in
the United States, rolling both stainless
steel and carbon steel grades. The new
plant concept developed by SMS Demag
for stainless-steel tandem mills consists
of several rolling mills in a tandem arrangement, with extremely slender and
therefore horizontally supported work
rolls.
Setting up a continuous rolling mill for
the production of stainless steel strip is a
cost-effective option where a cold-rolling
stage with a capacity of more than
400,000 t/year is to be implemented.
This plant concept requires the lowest
cost of conversion due to the as com-
pared to conventional stainless steel
rolling on reversing rolling mills higher
yield, less manpower and the lower
specific investment cost. The new plant
concept using rolling oil makes it possible to produce surface finishes that
bear comparison with cold rolled strip
produced in 20-roll mills. As compared
with the well-known fully integrated lines
for the production of stainless steel strip
(integrated rolling, annealing and pickling
lines), the concept of a continuous tandem mill has a much higher flexibility.
The differences between the continuous
tandem mills set up so far for the production of cold-rolled stainless steel strip are
as follows: The first mill in Japan was set
up as a semi-continuous line and has no
continuous exit. The mill stands are of
20-roll type and accordingly have long
roll-changing times of the backing elements and intermediate rolls. Another
critical item in this mill stand design is
the relatively poor accessibility in case of
strip breaks. The continuous tandem mill
at AK Steel was designed for the mass
production of carbon steels and austenitic as well as ferritic stainless steels. The
rolling mills are of four-high (mill stands 1
to 3) and six-high type (mill stands 4
and 5. The roll diameters were chosen to
suit stability requirements and the
torques needed to drive the work rolls,
they warrant a simple mill stand design
with associated high service life and
availability. Thanks to the application of
a special cooling lubricant and the use of
the required roll roughness it has also
been possible to satisfy customers' surface finish demands. The new
SMS Demag concept for a continuous
rolling mill for stainless steel strip is
based on the quality requirements of a
specialized cold strip production using
20-roll mills. To achieve the necessary
overall reduction, a very slender work roll
was chosen which via laterally arranged
In the production of cold-rolled stainless
steel strip in continuous tandem mills,
the following special technical items
need to be considered:
intermediate rolls is supported on both
sides by two rows of backup bearings.
The mill stand design encompasses a
six-roll mill with backup, intermediate
and work rolls. The intermediate rolls are
axially shifted and equipped with a roll
bending facility. The tandem rolling mill
is equipped for fully continuous operation, i. e., on the entry side a welder
and strip accumulator to bridge the nonproductive entry time are arranged,
whereas on the exit side coils are
changed on the fly. The above requires
the exit tension in the last mill stand to
be maintained with the help of a pinchroll mill stand and the continuous supply
of paper through the use of carousel-
suitable cooling and lubrication systems as well as an effective surface
inspection.
▬ The benefit of the lower specific investment cost becomes fully effective
especially in a modular mill design.
type paper winders and automatic
threading devices.
bearings, absorb the horizontal forces
▬ The large variety of the products to
be rolled in terms of their dimenions
and mechanical properties requires
an adapted mill stand design.
▬ The benefit of the high yield can be
achieved only in continuous operation.
▬ The excellent surface finishes can be
achieved only through the use of
The mill stand design follows the requirements of the rolling process. The necessary small work-roll diameter results
from the strength of the material and the
finish gauge to be achieved. Since the
degree of slenderness in the necessary
work-roll dimensions becomes too large,
these rolls need to be supported horizontally. Lateral backup rolls, which are additionally guided by two rows of backing
and transmit them to the adjustable support bridges. The benefits of this mill
stand design mainly include the application of the CVC plus® technology for setting the roll-gap geometry, the use of the
HS (horizontal stabilization) system for
optimization of the horizontal forces and
above all a quick work and intermediate
roll change.
Another important criterion for the design
of a tandem rolling mill for cold-rolled
stainless steel strip is the temperature
control in the rolling process. The cooling
lubricant used to attain the required surface finishes has a limited heat absorption capacity and the deformation energy
is predominantly transformed into heat,
i. e., the temperature of the material
rises. The compact design of the rolling
mill further allows the limited installation
of cooling sections. An exact prediction
of the material temperature forms the
basis for the production of excellent surface finishes with very good gloss and
reflection properties.
The already mentioned cooling and
lubricant system of the rolling mill essentially has to satisfy two requirements: on
the one hand it must support a high
thickness reduction at relatively low rolling speeds while on the other hand it
has to produce the gloss properties of
the cold-rolled strip surface. The benefits
of SMS Demag's cooling lubrication
technology consist of the technological
know-how of the cooling lubricant's
pressure absorption capacity, lubrication
effect, cooling efficiency, the filter tech-
nology which for this rolling duty is based
on the SUPAFINE® technology and the
technological design of the coolant system with the additional possibility of
setting different viscosity levels of the
lubricant in the various mill stands.
In SMS Demag's CVC® 18-HS rolling
mills, the potential flatness position errors of the cold rolled strip are compensated by tried-and-tested quick-response
actuators. Intermediate-roll bending and
edge-oriented shifting of the intermediate
rolls allow a very good correction of strip
edge waves and center buckles. However, the high degree of slenderness of
the work roll as well as the absence of
bending on the latter limit the potential
for correction in the case of so-called
quarter buckles.
To be able to use this additional adjustment potential, SMS Demag has developed a special CVC plus® grinding for
the 18-HS rolling mills.
In addition to the expanded control range
of the roll-gap geometry, this CVC plus®
grinding features an improved distribution of rolling forces over the length of
the roll barrel and thus across the entire
strip width, thereby increasing the service life of the rolls in the mill stands.
The HS system installed in
SMS Demag's rolling mills allows the
horizontal shifting of the work roll in the
direction of rolling as a function of the
predicted horizontal forces caused by
the drive torque. This allows high thick-
ness reductions during each rolling pass,
a longer service life of the lateral backing
elements and, through the integration of
the CVC plus® system in flatness control,
an excellent strip quality.
The HS system with its adjustable horizontal offset of the work rolls reduces the
necessary supporting force which needs
to be absorbed by the lateral backing
elements. A more stable rolling process
and lower maintenance cost are the essential benefits of this technology.
As a competent partner, SMS Demag
has a large number of reference installations at its disposal. This basis warrants
the efficient processing of projects as
well as a quick start of production. The
modular design of SMS Demag's rolling
mills, which has been successfully employed many times before, guarantees a
high availability and low operating cost.
SMS Demag offers rolling mill owners reliable solutions and high-quality engineering at a cost-benefit ratio in line with
the market.
Continuous tandem cold mills for stainless steel
Applications
SMS Demag
continuous
tandem mills
Nisshin Steel
AK Steel
combined
stainless steel/carbon steel
stainless steel
1969
1999
2007
1
Advantages for stainless steel
▬ High productivity ⇒ capacity of more than 400,000 t/year
▬ Lowest conversion costs:
highest yield
less personnel
low specific investment costs
▬ Excellent quality
▬ High flexibility compared to fully integrated lines
2
Existing plants
Nisshin Steel
Continuous four-stand 20-high tandem mill
Main data
material:
stainless steel
max. rolling speed:
600 mpm
capacity:
220,000 t/year
3
Existing plants
AK Steel
Continuous five-stand four-high/six-high tandem cold mill
Main data
material:
carbon steel
stainless steel (austenitic, ferritic)
max. rolling speed:
1,900 mpm
capacity:
3,600,000 t/year
4
Advanced SMS Demag tandem mill
Four-stand CVC® 18-HS tandem cold mill
Main data
material:
stainless steel
max. rolling speed:
400 mpm
capacity:
720,000 t/year
5
Tandem mill technology for stainless steel production
Wide range of products
Increase in
output/yield
Continuous rolling,
two-high tension stand
Top surface quality for
subsequent processing
SUPAFINE® filtration
Quick and reliable
strip surface control
Inline inspection
Low maintenance and
operational costs
CVC® 18-HS technology
6
Modular and robust mill design
Line concept for cold rolling of high-strength steels
Admissible and required line load [kN/mm]
Required line load for
strip thickness of 0.2
0.4
0.8 1.6 mm
CVC plus® 18-HS
four-high
no horizontal
horizontal
stabilization required stabilization required
Work roll diameter [mm]
Example:
Tensile strength 1000 N/mm², reduction 40 %, strip width 1300 mm
7
CVC plus® 18-HS
Benefits compared to the conventional 18-roll mill
▬ CVC plus® technology

improved roll gap setting and thus
improved strip flatness

equal load distribution between the
rolls and thus reduced roll wear
▬ HS system (Horizontal Stabilization)

reduced load of horizontal backing
rolls

less wear of backing rolls
▬ Easy roll change
by installation of intermediate, work
and backing rolls in change cassettes
8
Simulation of strip temperature
9
Requirements from the rolling process
High reduction under
low rolling speed
Optimized roll coolant system
in terms of cooling,
lubrication and filtration
High surface quality
demands 2B
High-performance
rolling oil with excellent
lubrication and cooling properties
10
Advantages of SMS Demag coolant technology
Design of the rolling oil system allows
optimum adaptation to the rolling process
in terms of heat removal and lubrication.
Highest cleaning efficiency due to a
SUPAFINE® filtration system and
magnetic separator.
Environmentally friendly concept as
no filter aid is required.
Viscosity can be adapted to each mill
stand by means of inline coolers.
11
Available flatness actuators of 18-roll mills
flatness defects
center buckles
flatness actuators
result
▬ IMR bending
▬ strip-edge-oriented
IMR shifting
significant improvement
edge waves
▬ small influence with
IMR bending and
conventional shifting
quarter buckles
▬ insufficient influence
of multi-zone cooling
CVC® 18-HS
12
no significant improvement
Principle of CVC® 18-HS
Axially shiftable IMR with
special CVC® shape of
higher order
▬ Flatness control of higher
order defects possible
(strip edge and quarter
buckles)
▬ Due to special CVC® shape
smooth load distribution
between WR and IMR
achievable
13
Comparison: Roll-gap adjusting field on conventional
18-roll and CVC® 18-HS mills
Mill data:
WR dia.:
140 mm
IMR dia.:
355 mm
BUR dia.: 1,350 mm
ben
ding
CVC®18-HS
mill
IMR
R
IM
Conventional
18-roll mill
ifti
sh
ng
Strip width:
1,200 mm
Spec. rolling force: 10 kN/mm
14
CVC® 18-HS mill with reduced work roll diameters
Horizontal Stabilization system (HS):
Work rolls can be laterally shifted depending on
strip data and rolling conditions.
▬ More than 15 references worldwide
▬ Ideal solution for stainless-steel tandem mills
Features
Advantages
Reduced work roll diameters
High thickness reduction possible
Horizontal Stabilization (HS) of
work rolls (SMS Demag patent)
Longer lifetime of side support
clusters due to adjustable force
Flatness control by proven IMR
bending and axial shifting system
(CVC plus® )
Excellent strip quality
15
Principle of Horizontal Stabilization system (HS)
with HS system
system
without HS system
FR
FR
rolling direction
FD
FD
required
supporting
force
FTo
required
supporting
force = 0 FTo
FT1
e (shift) FT1
FR rolling force
With HS system:
supporting force can be adjusted
FD tangential drive force
▬ Stabilized rolling process
FTo strip tension force entry
▬ Longer lifetime of side support inserts
▬ Less maintenance
FT1 strip tension force exit
horizontal
roling force
component
16
Benefits of SMS Demag technology
▬ SMS Demag is a competent partner in process technology
▬ Great number of reference plants with proven
technology fast start-up and reliable operation
▬ Low operational cost and high availability due
to modular design
▬ Excellent quality, high reliability, always on time
▬ Reasonable cost-benefit ratio
17
The new galvanizing line
for SeAH Steel –
Results and experiences
Dipl.-Ing. Werner Haupt
General Manager
Preacquisition and Integrated Projects
Y. J. Lee
Director
Dipl.-Ing. Joachim Kuhlmann
General Manager Process Engineering
Strip Processing Lines Division
SeAH Steel Corp.
Kunsan-City, Jeonbuk, Korea
SMS Demag AG
Hilden, Germany
The new galvanizing line for SeAH Steel Results and experiences
Y.J. Lee, Werner Haupt, Joachim Kuhlmann
The new and also first hot-dip galvanizing line of SeAH Steel Corporation is the
heart of the new cold rolling mill complex
built in Gunsan in the western part of
South Korea. The following topics report
on the construction of the facility by
SMS Demag as well as on our first operating results:
The subsidiaries of SeAH Steel include:
▬
▬
▬
▬
▬
Busan Pipe America Inc. (USA)
State Pipe & Supply Corp. (USA)
Vinapipe Corp. (Vietnam)
Saigon Steel Pipe Corp. (Vietnam)
SeAH Japan Co., Ltd. (Japan)
The history of the company is as follows:
▬
▬
▬
▬
▬
▬
General overview
Market development
Layout/technical data of the CGL
Erection phase
First coil
Operation
1960
Establishment of the company
as Busan Steel Industry in
Gammandong, Busan City.
1979
to 1982 Acquisition of several
▬ Results and experiences
SeAH Steel Corporation specializes in
the production of steel pipes, stainless
steel pipes for gas and water plumbing
installations in buildings as well as galvanized strip and pre-coated material.
The annual production capacity is more
than 1,200,000 t.
Besides supplying the domestic market,
high export rates to the USA and Japan
are achieved.
specialist companies for the production of steel pipes.
1996
The companys name was
changed into SeAH Steel
Corporation.
2005 Completion of the new cold
rolling mill complex in Gunsan.
As part of the new cold rolling mill
in Gunsan, the agreement with
SMS Demag for the supply of a hotdip galvanizing line was signed on
November 28, 2003.
With a market share of 660,000 t, SeAH
Steel covers 22 % of the demand for
steel pipes in the South Korean market
and is South Koreas biggest enterprise
in this product sector.
With 350,000 t of cold rolled steel, galvanized and pre-coated strip, SeAH
holds just a small market share among
the big players and has to compete with
producers which, owing to the size of
their companies, are able to produce
high-grade products at favorable cost.
The new galvanizing line has been designed for the production of hot-dip galvanized steel strip of the steel grades
CQ, DQ, DDQ and FH (full hard). These
products are used for white goods, in
the electrical and building as well as the
construction industries.
Designed for an annual capacity of
300,000 t, the line galvanizes strip 0.23
to 1.8 mm thick and 600 to 1,300 mm
wide. In the coating section, the strip
runs at speeds of up to 200 m/min, while
the entry and exit sections attain speeds
of maximum 280 m/min.
The line configuration is following the
demand for hot-dip galvanized strip of
highest surface quality. Pre-cleaning
takes place in the entry section and full
cleaning right upstream of the furnace.
To facilitate installation, the vertical strip
loopers feature a new modular design.
They are completely balanced and
equipped with a redundant drive system
with amply dimensioned ropes to ensure
reliable operation and a long service life.
The radiant-tube-heated Drever furnace
with a capacity of 73 t/h and the highly
precise Duma air-knife system complete
the process section.
Downstream of the four-high skin-pass
mill and the tension leveler unit, a vertical coater takes care of passivating the
strip.
The new galvanizing line of SeAH Steel
was built by a consortium comprising
SMS Demag AG, Germany, Drever
International S.A., Belgium, and Duma
GmbH, Germany.
Picture 6 shows the steel structures of
the two cleaning sections during erection.
Picture 7 on the left shows the area of
the post-treatment section during installation. The picture on the right reflects
the line from the entry looper system, via
the center cleaning section up to the
vertical furnace.
Erection started in November 2004 and
was completed in June 2005. In total,
more than 4,000 t of machines and steel
structures were installed. As early as
21 months after contract signing, the
first galvanized coil was produced.
Thanks to the excellent performance of
all suppliers under the leadership of
SMS Demag and the superb cooperation between the consortium and SeAH
Steel, the first saleable strip was produced four weeks before the scheduled
contractual date.
Picture 8 shows the festive celebration
of production start, which is a very important ceremony in the Korean self
understanding and culture.
As a result of this early and successful
hot commissioning, the full production
capacity was already achieved after
23 months and the Final Acceptance
Certificate (FAC) was issued as soon as
after 21 months.
Picture 9 on the top shows the vertical
post-treatment section in operation with
roll coater, drying oven and air coolers.
The right bottom picture reflects the operation of the line in the area between
the pre-cleaning section and the vertical
furnace. The picture provides a clear
view of the entry-end vertical looper arranged between the two cleaning sections. The picture on the left is a top
view of the Duma air-knife system.
The remarkably steep run-up curve of
the line is documented by the following
production evaluations covering the initial months after line startup.
▬
▬
▬
▬
▬
Run rate
Production volume
Yield
Run-up curve
Coating tolerances or accuracy
Already in the first month, the line attained a relatively high availability of
74.5 %, and from the end of the third
month on, the values stabilized around
the target of 98 %.
Picture 12 reflects the volumes produced for direct sales and for processing
in the own color-coating section.
It is obvious also in this case that the
line achieved its planned production
after a short time.
Picture 13 represents the ratio between
input material and finished products. A
high value means, for example, low
scrap losses. As early as in the second
month, the target value of 98 % was exceeded. Values of over 100 % may result owing to a weight increase due to
coating.
The run-up curve is the best way to describe the performance of the line as a
combination of availability and yield.
Just one month after commissioning, the
value stabilized around the target of
96 %, and after eight months ideal values of nearly 100 % were achieved.
The coating accuracy is one of the most
important factors for the product quality
and, when zinc prices are high, decisively impacts the operating costs.
Thanks to the Duma air-knife system,
coating uniformity is more than satisfactory. Currently, each 1 % in closer
coating tolerances reduces operating
costs by up to EUR 1 million per year.
The new galvanizing line for SeAH Steel
Contents
▬ General overview
General
overview
Market
development
Layout
▬ Market developments
▬ Layout/Technical data
Erection phase
▬ Erection phase
First coil
▬ First coil
Operation
▬ Operation
Results and
experiences
▬ Results and experiences
1
Company profile
SeAH Steel Corporation is specialized in the production of
General
overview
Market
development
▬ steel pipes,
▬ stainless steel pipes for plumbing and structures,
▬ galvanized steel and pre-coated metal
Layout
Erection phase
Annual production capacity: 1,200,000 t of steel products
First coil
Export of products to the USA and Japan
Operation
Subsidiaries:
Results and
experiences
▬ Busan Pipe America Inc. (USA)
▬ State Pipe & Supply Corp. (USA)
▬ Vinapipe Corp. (Vietnam)
▬ Saigon Steel Pipe Corp. (Vietnam)
▬ SeAH Japan Co., Ltd. (Japan)
2
Company history
1960
Establishment of the company as Busan Steel Industry
in Gammandong, Busan City
1979 - 82
Several acquisitions of specialized companies
1996
Change of company name into SeAH Steel Corp
2005
Completion of new CRM in Gunsan area
General
overview
Market
development
Layout
Erection phase
First coil
Operation
Results and
experiences
28.11.2003 Purchase agreement with SMS Demag
for the new CGL
3
Market shares
Market share steel pipe
(in '000 t)
General
overview
Market
share
Portion
in %
Hysco
495
16.4
SeAH Steel
660
21.9
Husteel
273
9.0
Others
1,591
52.7
Total
3,019
100
Market
share
Portion
in %
Hysco
1,437
12.1
Posco
6446
54.1
Dongbu Steel
1,837
15.4
932
7.8
1,258
10.6
11,910
100
Hysco
Market
development
Seah
Steel
Others
Layout
Husteel
Erection phase
First coil
Market share Cold rolled steel
(in '000 t)
Operation
Union Others
Steel
Results and
experiences
Hysco
Dongbu
Steel
Union Steel
Posco
Others
Total
4
Continuous galvanizing line SeAH Steel, Korea
Technical Data:
General
overview
Products:
Application:
GI / CQ, DQ, DDQ, FH (full hard)
Market
development
Production capacity:
Strip thickness:
Strip width:
Line speed:
300,000 t/year
0.23 to 1.6 mm
600 to 1,300 mm
200 m min (process section)
Layout
White goods + construction
Erection phase
Operation
Results and
Experiences
5
Erection phase
Continuous galvanizing line
was built by a consortium
between
General
overview
Market
development
▬ SMS Demag AG, Germany
▬ Drever International S. A.,
Belgium
Layout
Erection phase
▬ Duma GmbH Germany
for air knife system
First coil
Operation
Results and
experiences
All main equipment by SMS group
6
Erection phase
▬ 21 months from purchase
agreement to first coil
General
overview
Market
development
▬ erection period November 2004
until June 2005
Layout
▬ total weight: 4,114 t
Erection phase
First coil
Operation
Results and
experiences
7
The first coil was produced in saleable quality
four weeks before scheduled date
General
overview
Market
development
Layout
Erection phase
First coil
Operation
Results and
experiences
8
Operation
General
overview
▬ FAC after 21 months
Market
development
Layout
▬ Full production after 23 months
Post treatment
Erection phase
First coil
Operation
Results and
experiences
Air knife
Cleaning section,
entry looper and furnace
9
General
overview
Market
development
Layout
Erection phase
First coil
Operation
Results and
experiences
▬ Run rate
▬ Production of main products
▬ Benefit (output/input)
▬ Startup curve
▬ Coating accuracy
10
Run rate (prod. time/planned prod. time)
General
overview
Run rate target 98
Market
development
80
70
Results and
experiences
Sep 05 Oct 05 Nov 05 Dez 05 Jan 06 Feb 06 Mar. 06 Apr 06 May 06
First month
hrs: Production hours
Month
11
Production
General
overview
25.000
Layout
20.000
tons/month
Market
development
First coil
588.6 hrs
75
Operation
Erection phase
600.4 hrs
602.6 hrs
491.4 hrs
405 hrs
576.9 hrs
85
306.7 hrs
273 hrs
Rate (%)
First coil
90
437.7 hrs
95
Layout
Erection phase
%
100
15.000
10.000
Operation
5.000
Results and
experiences
Sep
05
Oct
05
Nov
05
Dez
05
Jan
06
Feb
06
Mar
06
Apr
06
Month
GI FOR SALE
12
MATERIAL FOR CCL
TOTAL
May
06
Benefit (output/input)
General
overview
Benefit target 98%
Market
development
110
Layout
100
Rate (%)
Erection phase
First coil
Operation
90
80
Results and
experiences
70
Sep 05 Oct 05 Nov 05 Dez 05 Jan 06 Feb 06 Mar 06 Apr 06 May 06
First month
Month
13
Startup curve
General
overview
Market
development
Erection phase
First coil
Rate (%)
Layout
Operation
Results and
experiences
100
90
80
70
60
50
40
30
20
10
0
Target startup curve 96 %
Sep 05 Oct 05 Nov 05 Dez 05 Jan 06 Feb 06 Mar 06 Apr 06 May 06
Month
First month
14
Coating tolerances
General
overview
Market
development
Layout
Erection phase
First coil
Operation
Results and
experiences
SeAH is very satisfied with the achieved coating
tolerances of the Duma air knife. Due to increased zinc
costs each 1 % improvement of tolerances reduces our
operation costs by approx. 1 million EUR per year.
15
Economical solutions for
high-quality processing lines
Dipl.-Ing. Stefan Melster
General Manager
Technical Sales
Dr. Hans-Georg Hartung
SMS Demag AG
Hilden, Germany
Economical solutions for high-quality processing lines
Stefan Melster, Dr. Hans-Georg Hartung
While in the past many investment decisions were clearly made on the grounds
of technical preferences, the majority of
decisions nowadays is based on economic considerations or facts. The reference figure today is the total cost, figure 1. Costs such as the percentage of
depreciation, overheads and the prices
of raw materials cannot be influenced by
plant builders. Investment cost or, in
other words, the price of the line is a
matter of technical requirements and so-
SMS Demag today offers the full range
of high-quality strip processing lines with
obviously significant economic advantages, figure 2, as demonstrated by the
large number of recent references. Besides 13 continuous pickling lines and
coupled pickling lines/tandem cold mills,
six color coating lines, twelve continuous
annealing lines and 14 galvanizing lines,
SMS Demag has during the last six
years received orders for more than
70 further strip processing lines. Among
lutions or, respectively, a matter of negotiation and by far not the most important
factor. In the long run, it is the cost for
maintenance, yield loss, staff and consumables that makes the difference between standard lines and economically
and profitably operating processing lines.
these are high-tech lines like silicon strip
processing lines, processing lines for
aluminum strip or acid regeneration
plants.
For about ten years, our development of
new equipment and the optimization of
existing components have been following just one guideline to improve the
customer benefit and profit. This can on
the one hand be achieved by technical
improvements which have an economic
impact, but also by cost-cutting with a
subsequent price reduction which is
based on a different design, but does not
affect equipment performance.
Figure 3 is a summary of our latest major worldwide references. Our guideline
for achieving best total cost of ownership
can be best explained by two recent examples: the pickling line of the new
coupled pickling line/tandem cold mill of
Baosteels cold rolling mill No. 5 and the
continuous galvanizing line No. 3 of
US Steel Kosice in Slovakia.
Figure 4 is a sectional view of Baosteels new PLTCM, designed for an annual production capacity of 1.74 million t
of steel, mostly high-quality grades for
the automotive industry. To explain the
cost-saving potential of our technologies,
three examples are provided of which
more details will be shown:
▬ the turbulence pickling technology
▬ the horizontal loop accumulator
▬ the ASC side trimming shear
Since the early 50s, SMS Demag has influenced the design of all types of highperformance pickling lines all over the
world. Meanwhile all components for
pickling lines including mechanical and
chemical equipment, even acid regeneration plants and laser welding machines,
can be supplied from one single source.
This is a benefit to our customers as it
involves a consistent process technology
and minimizes potential interface problems.
ment of the acid temperature, due to less
acid circulation volumes. This improves
process flexibility. The immersion cover
seals off the pickling channel towards
the top and thus prevents any free acid
surface and acid evaporation in the pickling tank, which leads to significant energy and operating cost savings. By injecting the acid at high pressure from the
entry and exit sides into the pickling
channel and onto the strip, the turbulent
acid flow and the acid exchange on the
strip surface are increased through the
high input of kinetic spraying energy.
The turbulence pickling method, figure 5, developed by SMS Demag, is not
only the most effective, but also the most
economical pickling technology in terms
of operating cost. The design of
SMS Demags turbulence pickling line is
characterized by shallow and horizontal
pickling channels, the patented immersion covers and acid injection by spray
During the pickling process the entire
pickling channel is filled with acid,
whereas the entry- and exit-side acid injection serves for hydrodynamic sealing
of the pickling channel, figure 6. This
ensures wetting of the full strip surface
even at high strip speeds, as well as an
improved acid separation between the
pickling tanks. The high intensity of the
turbulence pickling line allows a very
compact design of this process section.
Steam and power consumption as well
as acid losses are significantly lower
than in conventional pickling systems,
due to the immersion covers. A much
faster heat transfer from acid to strip and
headers on the entry and exit sides of
each pickling tank. The straight, horizontal channel which is integrated into the
main pickling tank, allows operation of
the line at high strip tension for improved
strip guiding. Its small height of about
150 mm not only ensures a high acid
flow velocity and hence large turbulences, but also a much faster adjust-
more intensive acid exchange at the strip
surface can be achieved through the
high kinetic spraying energy. This leads
to a better acid utilization and an accelerated pickling process. Due to the good
controllability of the process, no pickling
inhibitors are necessary. The rinse section has a second spray rinse circuit in
order to avoid staining during line stops.
Therefore, no rinsing inhibitors are
needed here either. For a pickling line
with a production capacity of about
1.8 million t/year, annual savings may
total 600,000 EUR just because of the
above-mentioned features.
of the SMS Demag process model may
result in further savings of up to
300,000 EUR per year due to reduced
power and fluids consumption.
The turbulence pickling process can be
further optimized through the application
of SMS Demags process model, figure 7, which sets all essential pickling
parameters to the relevant strip quality
automatically and ten to 20 coils in advance. The main objective is to prevent
SMS Demags horizontal looper system,
figure 8, is characterized by two main
features: the retained looper car and the
Maltese-cross looper gate design. The
retained looper car means that the
looper car is pulled on each side by
ropes, whereas other systems use a
rope for pulling on one side and the strip
only for pulling on the other side. The ad-
underpickling or overpickling and to set
the lowest possible acid temperature.
The lowest possible bath temperature
means minimum energy and acid consumption, but also an increased lifetime
of all equipment exposed to acid. A 5 °C
drop in the bath temperature may result
in a 50 % longer lifetime of plastic pipes.
vantages of our system are lower tension fluctuations and a more stable
looper car operation. Constant strip tension and thus untroubled operation of the
coupled tandem mill is not the only benefit of the closed loop system. For maintenance purposes the looper car can be
moved without strip in the line.
Part of this process model is the simulation of the pickling process for incoming
coils. Based on all major pickling and
strip parameters, the pickling result can
be controlled by the correct setting of the
acid pressure in consideration of the
strip speed and the required bath temperature. The model controls the transi-
Due to the Maltese-cross looper gate
system, the looper gate arms can be
opened and closed smoothly by the
looper car without any shock even at
high looper car speeds. The special mechanism leads to a soft acceleration and
deceleration of the looper arm without
inertia-caused overloading of the me-
tion from one strip to the next, so that the
pickling process is adapted to the next
strip without any visible change in the
pickling results. In addition to the abovementioned cost savings, the application
chanical parts. Frequent consequential
damage can thus be avoided. Each damaged gate costs a total of approx.
90,000 EUR. These expenses for
spares, maintenance work, production
loss and fixed costs can be saved.
The combined ASC side trimmer and
chopper unit is one of the most impressive cost savers in our lines, figure 9.
On each side of the line two trimming
shears with associated scrap choppers
are mounted on a turntable platform in a
180-degree arrangement. This arrangement allows the safe maintenance of the
standby trimmer/scrap chopper unit also
during production, with the other unit in
operation. All settings of the knife gap
and knife overlap are performed
automatically by eccentrics. In
comparison, linear shifting devices with
During a width change, the complete
side trimmer and chopper unit will be readjusted within seconds without producing any extra scrap. Our design avoids
the above-mentioned typical operational
problems, i. e. unscheduled downtimes
for troubleshooting like scrap jam removal. Even in the unlikely case of trouble or
in case of normal maintenance, the
whole system together with its problem
is simply turned out of the line and replaced by fully operative equipment within 60 seconds. The problem can then be
fixed in the safe 180-degree position
bushes tend to wear and are always a
matter of maintenance. In contrast, eccentrics are backlash- and almost maintenance-free. Due to the automatic knifegap and knife-overlap setting, an extended lifetime of the blades and improved cutting qualities can be achieved.
The knife blades are face-ground and
mounted against mechanical stops,
therefore no calibration is required after
a blade change.
while the line is running. With one
trouble per week, this ASC side trimming
system can save up to 1 million EUR per
year in high-performance pickling lines.
The combined ASC side trimmer unit is
not only used in our pickling line, but also in most of our other strip processing
lines.
The side-trimmings chute between the
trimmer and chopper is undivided without any gaps. Gaps in the side-trimmings
chute are usually the cause of scrap
cobbles and each cobble can take
approximately one to two hours to be
removed.
Another good example for economical
processing-line solutions is the new galvanizing line No. 3 of US Steel Kosice,
figure 10. This is a typical line for the
production of exposed automotive material with GI and GA coatings. Highly sophisticated structural steel grades are also part of the product mix.
The total-cost-of-ownership guideline is
explained by the following examples:
▬
▬
▬
▬
Coil transport system
Cleaning section
Air knife
Post-treatment/coating section
Our coil cars, figure 11, are of extremely
compact and flat design and do not need
any deep, expensive and eventually also
dangerous foundation pits. Still they are
as sturdy as necessary for metallurgical
works. As opposed to other scissorstype coil cars, the cylinder force acts in
the load direction and not in transverse
direction. The scissors just have a guiding function, but do not transmit any
load. Besides safety and maintenance
aspects, the cost reduction for the foundations of three coil cars is about
70,000 EUR.
Our strip cleaning sections, figure 12,
are characterized by three main features. First, sealed modules with lower
required fume exhaust volumes at the
connection points of the modules reduce
energy losses significantly. Second, the
changing of rolls is fairly easy and can
be done during operation with no additional downtimes or maintenance work
required. Finally, special tongue-shaped
spray nozzles guarantee a clog-free operation. No clogging means no surface
stripes, no subsequent downgrading and
no prematurely damaged brush rolls.
Based on European cost basis, up to
600,000 EUR can be saved per year.
SMS Demag can provide two primequality air knife systems: Fontaine and
Duma, figure 13. Both air-knife systems
are technically excellent. Both can be
equipped with width-adjustment actuators without any negative influence on
the surface quality produced. Depending
on the product mix, such a blow-off width
adjustment can save up to 30 % of compressed air or, respectively, nitrogen. In
the production of automotive strip such
nitrogen savings can add up to
1 million EUR a year in case the nitrogen
has to be purchased. The high precision
of our air knife systems results in closer
coating tolerances than in other systems.
A mere 1 % more precise coating can
save zinc worth up to 1 million EUR per
year in a typical hot-dip galvanizing line
producing approx. 400,000 t/year and
approx. 190 million m² strip surface.
In modern lines that conform to the latest
health and safety standards, the heart of
the post-treatment section is the roll
coater, figure 14. Using two separate
circuits, our coaters can be used for
chromating as well as anti-fingerprint
coating. Due to the use of coated pans
and the automated cleaning and rinsing
system, a change in coating agent is not
very time-consuming. Alternatively, a
two-coater or shuttle coater system can
be provided. The rolls can be changed
without any major maintenance effort.
But the most impressive property is no
doubt the outstanding accuracy of the
coating. With this system, a coating accuracy of plus/minus a quarter of a micron can be achieved. In comparison
with other coating systems with accuracies of plus/minus 1 micron, this
means, in addition to other benefits, savings of up to 500,000 EUR per year for
the post-treatment system of hot-dip galvanizing lines. In color-coating lines,
three times this amount can easily be
saved due to the particularly high cost of
chemicals and paints.
All the above-mentioned examples are
the result of a continuous improvement
process, figure 15. All developments
must follow the total-cost-of-ownership
guideline. This means that improvements must pay off to our customers in
terms of reduced operating cost, less
energy consumption, less maintenance,
less downgrading, higher yield or a marketable better product quality. All these
economical solutions for high-quality processing lines are incorporated in our latest reference list and have been successfully commissioned. As a consequence, a steep ramp-up curve is part of
our customer benefit.
Introduction
Cost influence
by SMS Demag
Yield loss
Introduction
Strip
processing
lines
Staff cost
Consumables
& media
Maintenance
Pickling line
technology
Total cost
of ownership
Hot-dip
galvanizing line
technology
Investment
cost
Summary
Raw material
Overheads
Depreciations
No cost influence
by SMS Demag
1
Strip processing lines Major references since 2000
Carbon steel
13 CPL/PLTCMs
Introduction
Strip
processing
lines
Pickling line
technology
6 CCLs
in total more than
50 new processing lines
since 2000
12 CALs
Hot-dip
galvanizing line
technology
incl. seven lines for
silicon strip
1 ETL
Summary
incl. seven lines for
aluminum strip
plus approx.
60 service lines
14 CGLs
plus 13 new ARPs
2
Strip processing lines Major references since 2003
Customers and type of lines
Introduction
Strip
processing
lines
Pickling line
technology
Hot-dip
galvanizing line
technology
Summary
Tokyo Steel
CPL + ARP
Shougang Jing-Tang
CAL
Nucor
CGL
ILVA Taranto and Cornigliano
2 CGLs
Baosteel
4 Si-lines
Tiantie
PLTCM
Salzgitter
CPL
SeverCorr
CGL + PLTCM
Baosteel
Baosteel
CAL + PLTCM
PLTCM
Shougang
CAL + PLTCM
US
USSteel
SteelKosice
Kosice
CGL
CGL
Jinan
CPL
WISCO
3 CGLs + CAL + PLTCM
Anshan
CAL
Seah
CGL
Rasselstein
ETL
3
Pickling line/tandem cold mill
Baosteel, Baoshan/China
Introduction
Pickling line
technology
Hot-dip
galvanizing line
technology
Summary
Technical data
Products: CQ, DQ, DDQ, EDDQ, SEDDQ, DP, Trip
Strip thickness
Strip width:
Pickling speed:
1.8 to 6.0 mm
700 to 1,650 mm
270 m/min
1,740,000 t/year
4
Turbulence pickling technology
Introduction
Strip
processing
lines
Turbulence pickling channel
Immersion cover
Outer cover
Pickling tank
Pickling line
technology
Hot-dip
galvanizing line
technology
Summary
▬ Flat and horizontal pickling channel
▬ Immersion covers less acid evaporation
▬ Hydrodynamic sealing
5
Heat exchanger
Steam
Condensate
Introduction
Acid supply
piping
Strip
processing
lines
Pump
Pickling line
technology
Cascade piping
Waste acid
Turbulence pickling tank with circulation system
Hot-dip
galvanizing line
technology
Summary
Draining chamber with spray bars and
squeegee roll unit (hydrodynamic sealing)
▬ Better controllability due to less acid volumes in circulation
▬ Less steam, acid and energy consumption due to immersion covers
▬ No pickling and rinsing inhibitors
▬ Lower possible acid temperature less energy, longer lifetime
Total potential on cost savings: up to 600,000 EUR/year
6
SMS Demag process model for turbulence pickling
▬ Minimized overpickling:
Introduction
less material loss
less energy
Strip
processing
lines
Pickling line
technology
Hot-dip
galvanizing line
technology
higher yield
▬ Automatic setting and control of process actuators
▬ Minimized bath temperature
less energy
Turbulence
longer lifetime
Summary
Temperature
less maintenance
Total potential on cost savings:
up to 300,000 EUR/year
Strip speed
Desired bath temp.
7
High-speed looper concept Technical advantages
Steering Curve
Introduction
Strip
processing
lines
Tension Rope
Pickling line
technology
Retaining Rope
Hot-dip
galvanizing line
technology
Summary
Closed loop system
(two-side rope pulling)
▬ less tension fluctuation
▬ better maintainability
Maltese-cross looper gates
▬ impact-free opening and closing
▬ less damages
▬ longer lifetime
▬ less maintenance
Each damaged gate costs EUR 90,000
8
ASC trimming shear
Features:
▬ No line stop during
knife change
Introduction
Strip
processing
lines
▬ Easy and safe
maintenance access
Pickling line
technology
▬ No extra scrap during
width change
Hot-dip
galvanizing line
technology
▬ No calibration of knives
after change
Summary
Potential cost savings up to 1 million EUR/year
due to less downtime
9
Continuous galvanizing line
US Steel Kosice, Slovak Republic
Technical data:
Products: CQ, DQ, DDQ, EDDQ, SEDDQ, HSS-CQ,
HSS-DQ, HSS-DDQ, BH, DP
0.3 2.0 mm
Strip thickness
800 1,850 mm
Strip width:
Process speed:
180 m/min
410,000 t/a
10
Coil transport systems
SMS Demag technology
Introduction
Strip
processing
lines
Pickling line
technology
Hot-dip
galvanizing line
technology
▬ Coil cars with extremely flat
design and rigid design for
metallurgical works
▬ Guiding scissors are loadfree
▬ No expensive and
dangerous foundation pits
▬ Good maintainability
Summary
Reduction of foundation cost
up to 70,000 EUR
11
Strip cleaning section
Introduction
Strip
processing
lines
Pickling line
technology
▬ Sealed modules less energy
▬ Easy roll changes less
maintenance
▬ No clogging no brush roll
damages, no stripes, no
downgrading
Hot-dip
galvanizing line
technology
Summary
Potential cost savings: up to 600,000 EUR/year
12
Air knife
Introduction
Strip
processing
lines
▬ Width adjustable
▬ Outstanding coating accuracy
▬ Minimized over-coating
Pickling line
technology
Hot-dip
galvanizing line
technology
Possible reduction of production costs per year:
Summary
up to EUR 1,000,000 nitrogen savings for customers
without oxygen plants
1 % better coating accuracy = approx. 1,000,000 EUR
cost savings for zinc
13
Post-treatment
Introduction
Strip
processing
lines
Pickling line
technology
Hot-dip
galvanizing line
technology
▬ Outstanding coating accuracy
▬ Simple roll change
▬ Automated cleaning of rolls, pans
and media systems
▬ Minimized over-coatings due to
higher coating accuracy
Summary
A coater accuracy of ± 0.25 μm instead of
± 1.0 μm can save up to 500,000 EUR/year
for post-treatment
14
Summary
The essentials of economical solutions are
Introduction
▬ Cost savings resulting from

Strip
processing
lines
Pickling line
technology
Hot-dip
galvanizing line
technology
less operating materials and energy consumption
less maintenance and longer service life
less downgrading of product quality
less downtimes and higher yield
▬ Better product quality
▬ Higher flexibility and faster start-up curves
Summary
15
The SMS Demag laser welding
machine
Dr. Hans-Georg Hartung
Dipl.-Ing. M.B.M. Markus Jaenecke
Senior Project Manager Project Planning
SMS Demag AG
Hilden, Germany
Dipl.-Ing. Lutz Kümmel
Senior Project Manager
The SMS Demag laser welding machine
Dr. Hans-Georg Hartung, Markus Jaenecke, Lutz Kümmel
Some three years ago, SMS Demag and
Oxytechnik, a German welder manufacturer, agreed to jointly develop a laser
welder for strip processing lines. Technology and design are the results of
many years of experience in designing
high-performance strip processing lines
and equipment as well as welding machines including laser welders for special
applications.
Nowadays, laser welding machines are
the first choice for continuous pickling
lines. These welders are meanwhile
cheaper than flash butt welders and
easier to commission, especially if new
materials or material combinations are to
be welded. In addition, these welding
machines are able to weld thinner strip
and strip with higher amounts of alloying
elements. Based on the experiences
gained from many projects, we developed a new laser welder design. Thanks
to the closed-frame concept, the machine is more compact than C-frametype machines and can usually be transported on trucks.
The laser resonator is fixed on a separate foundation. No resonator vibrations
will influence the welding accuracy. For
maintenance purposes, access to the
machine as well as to the resonator is
excellent.
Another remarkable feature is the positioning system that aligns the head end
of the new strip with the tail end of the
previous strip. That means that it is the
center line of the leaving strip that defines the correct alignment, and not the
center line of the machine. After joining,
the two strips will have one common
center line and definitely no so-called
dog-leg shape. One of the biggest advantages is that the strip edges will not
be damaged. The clamping of the strip
will not be interrupted until welding is
finished.
The integrated shear is not a notchertype shear with more or less no gap between top and bottom knives. Such a design leads to huge perpendicular forces
acting on the knives and subsequently to
high wear and less accuracy. The laser
welder consists of a robust, mill-type-design dividing shear with automatically adjustable knife gaps separately for the
outgoing and ingoing strip ends. The
knife crossbeam is supported at several
positions across the width and doesnt
allow any relevant breathing. The blade
lifetime is at least three times as long as
for other laser welders and, due to the
cassette design, the blades can be
changed easily by an electro-hydraulically changing device. The top knife can be
used twice, the bottom knives four times
before regrinding. The precise cut has
the potential to allow using lasers with
less power in the future because the defocusing of the beam can be reduced.
This leads to less laser power and consequently to a longer laser lifetime. For
the same reason we expect that more
and more Neodymium-YAG lasers will
be used in the near future instead of
high-power CO2 laser sources. One major advantage is the possibility to feed
the beam via fiber-optic cable to the weld
spot subsequently no mirrors can be
contaminated.
ferrite and perlite. Post-annealing and
particularly preheating and post-annealing led to a highly uniform hardness distribution in the vicinity of the weld as
compared to the results without annealing. In order to ensure the best possible
heat treatment of the weld, new inductive
pre- and post-heaters were developed
together with our sister company
SMS Elotherm. The main features are
fast heating during preheating and postannealing with retarded cooling.
Early in 2006, we received an order from
The shear remains in the machine during
welding. Therefore, we could avoid the
either heavy or flimsy C-frame design.
Scrap can be discharged directly into a
pit or be removed by a conveyor belt.
In case of different strip thicknesses, the
joint can be made centrically, top side or
bottom side orientated. Real zero-gap
welding is possible due to the shifting
function of the strip clamping device.
As an option for special applications a
wire feeder can be provided. Mixed gas
or helium is used as inert gas.
Along with the design work plenty of
laboratory tests were conducted. The
test results were very promising, even
for hard-to-weld steel grades like C60
with a carbon content of 0.67 %. The
cross-sections of the welds were excellent and so were the microstructures of
the heat influence zone and of the weld
itself. The main components of the microstructure of this high-carbon steel are
Salzgitter Flachstahl GmbH, Germany,
for a heavy-duty laser welding machine.
This laser welder for 800 up to 1,900mm-wide strip will be installed in a 2.5million-t/year continuous pickling line that
will also be supplied by SMS Demag.
The strip thickness ranges between 1.5
and 6 mm and the yield stress may exceed 1,100 N/mm². Some of the steel
grades are extremely difficult to weld
such as C60. The laser welder for Salzgitter is currently being tested in our
workshop. In April 2007 Tokyo Steel,
Japan, placed a further order for a laser
welder with us.
Development of SMS Demag laser welding machine
▬ In 2004, a cooperation between SMS Demag and
was established in order to develop a
laser welding machine for strip processing lines
Introduction
Main features
Laboratory test
Laser welding
machine for
Salzgitter
1
Laser beam source
▬ The laser resonator is fixed
beside the machine on a
separate foundation
Introduction
▬ No vibrations, no influence
on the welding accuracy
Main features
Laboratory test
▬ Easy access for maintenance
Laser welding
machine for
Salzgitter
CO2 laser resonator
2
Strip alignment
▬ Incoming strip head is aligned with the tail end of the
previous strip
Introduction
▬ Center line of the leaving strip defines the right alignment
Main features
▬ No pushers no strip edge can be damaged
Laboratory test
Laser welding
machine for
Salzgitter
3
Shear design
▬ Robust, mill-type design dividing shear with automatically
adjustable knife gaps separately for outgoing and ingoing
strip
Introduction
Main features
Laboratory test
Laser welding
machine for
Salzgitter
4
Shear design details
Multiple support of knife crossbeam
Introduction
Main features
Laboratory test
Laser welding
machine for
Salzgitter
▬ Knife lifetime triples
▬ Quick knife changes
▬ Precise cuts =
precise weld
Knife changing device
5
Welding process
▬ The joint can be made
centrically, top side or
bottom side oriented
Introduction
▬ For special steel grades a
wire feeder can be installed
Main features
Laboratory test
▬ For shielding, mixed gas or
helium is used
Laser welding
machine for
Salzgitter
6
Results of laboratory test
▬ Hard-to-weld steel grades
like C60 with a carbon
content of 0.67 %
were welded successfully
Introduction
Main features
Laboratory test
Laser welding
machine for
Salzgitter
▬ Cross-sections of the welds as well as the microstructure of
the heat influence zone and of the weld itself were excellent.
7
Influence on weld seam hardness by heat treatment
1000
Introduction
900
Probe 10.2
Probe 8.2
Probe 5.1
Pr. 5.1, Grundwerkstoff
C60, Anlieferung
800
Main features
HV1
700
Laboratory test
600
500
400
Laser welding
machine for
Salzgitter
300
200
-5,0
-4,0
-3,0
-2,0
-1,0
0,0
1,0
2,0
Position [mm]
▬ Fast preheating and soft postannealing with retarded cooling
Preheating and postannealing of coils
8
The new laser welding machine will be installed
in the new 2.5-million-t/year continuous pickling line
of Salzgitter Flachstahl GmbH
Introduction
▬ The order was placed in March 2006
Main features
Laboratory test
Laser welding
machine for
Salzgitter
▬ Carbon content up to 0.67 %
▬ Strip width between 800 and 1,900 mm
▬ Strip thickness between 1.5 and 6 mm
▬ Yield stress up to 1,100 N/mm²
▬ Pre-commissioning underway in our Hilchenbach
workshop
9
Innovative and flexible:
the Automatic Coil Transporter
(A.C.T.®) developed by SIEMAG
Dipl.-Ing. Bernd Klein
CEO
Dipl.-Ing. Volker Schneider
Project Manager Sales
Dr. rer. nat. Horst Thorn
Head of Sales Department
SIEMAG GmbH
Netphen, Germany
Innovative and flexible:
The Automatic Coil Transporter (A.C.T.®) developed by SIEMAG
Bernd Klein, Horst Thorn, Volker Schneider
Nowadays, flexibility and automation are
two of the most important objectives in
logistics planning. The operators of production plants are obliged to respond
quickly and flexibly to changes in general
conditions. The Automatic Coil Transporter (A.C.T.®) developed by SIEMAG
guarantees the maximum degree of flexibility required.
Many production plants in the steel, NF
metals and paper industries have grown
gradually over decades with investments
made mainly in new machines and modernization of existing ones.
In situations such as these, the A.C.T.®
developed by SIEMAG represents the
perfect solution.
Thanks to the laser navigation system,
the A.C.T.® can be used without having
to modify the existing transport routes.
The plant layout is stored in the navigation computer and all the possible routes
are programmed.
Due to increases in production volumes,
The overriding vehicle-management
computer selects the best available
vehicle and determines the best route
taking both source and destination into
account.
problems frequently occur with the logistics of the coils to be stored and transported.
This route is then transmitted to the
vehicle by radio.
Conventional conveyors such as walking
beams, chain conveyors or track-guided
cars can often only be integrated in existing production facilities at considerable
cost and effort. In particular, the foundation work required often leads to serious
disruption of the existing infrastructure.
Existing traffic routes and machinery
often prevent conventional solutions
from being adopted.
With the assistance of the navigation
laser and reflective foils mounted on the
building structure at a height of about
4 meters, the vehicle always knows exactly where it is and is therefore able to
cover the preset route automatically.
Communication with the host computer
also takes place at crossings, control
lights or gates, and the computer decides which of the vehicles has priority.
Traveling on and crossing these routes
with driver-controlled vehicles represents
no problem. Priority regulations can be
defined at points with a high traffic frequency and the drivers signal their arrival and departure simply be pressing a
switch.
The A.C.T.® on the other hand is fitted
with an elaborate safety system which
detects obstacles in good time and
brings the vehicle to a halt before a collision can occur. The A.C.T.® automatically continues its journey as soon as the
In addition to the scanners, pressure
strips are mounted on the vehicle just
above the floor. The vehicle also stops
when these make contact with an object
in its path.
The chassis design is another important
factor permitting the flexible use of the
A.C.T.® in existing plant layouts.
The vehicle is fitted with four steerable
heavy-duty wheel sets. These allow it to
negotiate very sharp bends and to turn
virtually on the spot.
obstacle has been removed.
This system is designed in full compliance with current EU guidelines and has
been approved by the employers' liability
insurance association as providing the
necessary degree of safety from injury.
The safety system consists of a combination of active and passive sensors providing the maximum protection possible.
In travel direction, the entire pathway is
monitored by laser scanners which point
in the desired direction when moving
around corners and bends.
Each of the wheel sets is mounted on its
own articulated bearing. The chassis is
also mounted on a three-point bearing
which means that the load is always
evenly distributed.
In order to avoid costly modifications of
travel paths, one of the high design priorities was to keep the specific floor
pressure as low as possible.
For this reason, heavy-duty wheel sets
were selected with twin tires and a diameter of 600 mm.
The driven wheels are fitted with a differ-
The area scanned is divided into two
zones. When an obstacle is detected, at
first only the speed is reduced. As soon
as the obstacle enters the critical second zone right in front, the vehicle is
stopped.
ential gear system in order to keep the
load on the floor and wheels to a minimum during steering maneuvers.
The motors used are standard threephase asynchronous motors controlled
by current inverters. This ensures optimum control behavior, which, in combination with the chassis design, means
that the vehicle is always accurately positioned.
the charging station until the charging
process was completed. These relatively
short but frequent intervals add up to a
considerable period of downtime in the
course of a day, thereby markedly reducing the efficiency of the system as a
whole.
Power is provided by standard lead-cell
batteries with capacitive operation, i. e.
the batteries are run until they are almost
completely discharged and then replaced by fully charged ones.
For this reason the SIEMAG designers
selected the substantially more economical solution of working with two batteries.
While the second battery then remains in
the vehicle for the next eight hours (approximately), the discharged battery is
re-charged at the special re-charging
station.
and high vehicle speeds in the loaded
state.
This procedure means that the downtime
is reduced to about ten minutes per shift
and the vehicle is available for transport
operations around the clock.
The charge status of the battery is monitored continuously, and when a certain
threshold value is reached, the vehicle
travels automatically to the battery-replacement point and docks in.
Batteries with a voltage of 288 V are
used to achieve maximum performance
This concept makes it possible to
achieve high efficiencies at low current
values and consequently high control reserves with the inverters, which are necessary for good movement dynamics.
At Hydro Aluminium in Hamburg, Germany, all the coil-transport operations in
the plant buildings were previously
carried out by fork-lift trucks and the coils
were stored in several small stores between the machines.
Due to the large number of manual oper-
The battery is then removed automatically and replaced by a fresh one.
Capacitive battery operation means that
significantly more transport operations
can be executed by one vehicle than if
the battery were partially re-charged
whenever required. This would mean
that the vehicle would have to remain at
ations involved, seamless, systematic
material tracking was virtually impossible.
The next coils to be rolled were summoned simply by calling to the fork-lift
driver.
In addition to this, a modernization program carried out in 2002 resulted in an
increase in production of around one
third.
In order to make logistics simpler and
more predictable, it was decided to store
all the coils in a central high-bay store
and use an A.C.T.® system for the transport operations.
Apart from normal maintenance work,
none of the larger parts have been replaced so far. Even the original Vulkollan
tires are still in use, although considerable doubt was initially expressed by the
customer here due to the aggressive
nature of the rolling oil.
Through the introduction of the A.C.T.®
system, the flow of material became fully
transparent; the position of each individ-
The first large replacement operation is
now becoming due because the batteries are exhausted after a total of
1,500 charging cycles. However, this operation was planned in advance since it
was known that the batteries are only
ual coil is now known at all times.
designed for 1,200 charges.
The coil movements are planned in advance with the result that the right coils
are always delivered to the right machine
at the right time.
After more than four years in operation,
the results obtained have fulfilled even
the most optimistic predictions.
Another serious disadvantage of transporting coils "manually" by fork-lift truck
and crane was also eliminated by the
introduction of the A.C.T.® system. Coil
damage in transit was cut down to almost zero which naturally meant a substantial improvement in product quality.
Each of the five A.C.T.® vehicles operated by Hydro Aluminium has meanwhile
covered a total of about 50,000 km and
transported more than 40,000 coils.
SIEMAG A.C.T.® Automatic Coil Transporter
Disadvantages of transporting coils by crane or
fork-lift truck
1
▬ Coil pick-up from floor, turnstiles, continuous conveyors or coil rests
▬ Max. payload 35,000 kg
▬ Integration in plants without modification of existing machinery
▬ Flexible traveling course, modifiable at any time; free navigation with laser
▬ No enclosed travel path required
▬ Chassis characteristics:
max. gradient:
max. single obstacle:
±2 %
±35 mm
2
Safety devices on the SIEMAG A.C.T.®
Switch plates
Reflective
sensor
Rotating beacon
Emergency
stop
buttons
Obstacle
detection
Full perimeter
mechanical
buffers
Virtual
buffers
3
Vehicle navigation
Dead reckoning (DR) navigation
Shaft encoder
Laser triangulation
Shaft encoder
Wheel 2 Wheel 1
Incremental
position encoder
Incremental
position encoder
4
A.C.T.® Chassis concept Main features
Four-wheel steering with twin tires and differential gears
▬ Extremely high maneuverability
▬ Travel in any direction possible
▬ Tight turning radii
▬ Exact positioning
▬ Safe load handling
▬ Low forces on wheel and floor
▬ Low wear on wheel and floor
5
Effect of battery concept on transport efficiency
Battery operation with intermediate charging
250
15 min 18 min
15 min
Coils
200
150
100
Battery charging
50
0
0
6
12
Time [h]
6
18
24
Battery operation with battery replacement
250
8h 15 min 8h
Coils
200
150
100
Battery replacement
50
0
0
6
12
18
24
Time [h]
7
Comparison of concepts
250
SIEMAG A.C.T .®
Battery change
220 coils
Coils
200
150
Battery charging
80 coils
100
50
0
0
6
12
Time [h]
8
18
24
Advantages of higher battery voltage
Effect of supply voltage on current
125,0
Power [KW]
100,0
75,0
50,0
25,0
0,0
0
50
100
150
200
250
300
350
400
450
500
550
Current [A]
288 V voltage (A.C.T.®)
▬ High power possible for high speed and
acceleration, even in loaded state
▬ Same power for significantly less current
▬ Lower cable diameter
▬ Standard asynchronous motors usable
80 V voltage
▬ High control reserve of power
inverters gives improved travel
dynamics
▬ Higher degree of efficiency
▬ High life span
9
Battery and battery replacement
▬ Capacitive operation
▬ Lead-acid battery
▬ Automatic battery
replacement
▬ 288 V battery voltage
10
A.C.T.® Profitability calculation
Savings
in total
Costs
Improvement
in quality
A.C.T.®
Labor costs
0
1
2
3
4
5
6
7
8
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
Months
Calculation basis:
Costs A.C.T.®:
Investment costs plus operating expenses
(e. g. energy, maintenance, staff)
Five persons for three-shift operation per vehicle
40 kg less damaged material per 20-t coil
Saving of labor costs:
Improved quality:
11
Material flow at Hydro Aluminium, Hamburg/Germany
HRM HBS:
200 m, 8 c/h
ANNEALING HBS:
150 m, 3 + 3 c/h
CRM 1 HBS:
70 m, 16 + 16 c/h
CRM 2 HBS:
50 m, 4 + 4 c/h
FINISHING HBS:
70 m, 3 + 11 c/h
12
Hydro Aluminium, Hamburg/Germany
13
Operating experience
Operating data :
▬ Operating hours per A.C.T.®: approx. 4,800 h/year
▬ Average cycle data per transport operation: 7 min, 260 m
▬ Number of transport operations per A.C.T.®: approx. 41,700 year
▬ Distance covered per A.C.T.®: approx. 11,000 km year
▬ Operating time so far: approx. 4.5 years
▬ Total distance covered per A.C.T.®: approx. 50,000 km
Maintenance/wear:
▬ Replacement of friction bearings and regrinding of horizontal
guides during maintenance work
▬ Replacement of traction batteries after approx. 4.5 years
at a maximum of 1,544 charging cycles
(Design: 4.48 years at 1,200 nominal charging cycles)
14
Main advantages of the SIEMAG A.C.T.®
▬ High transport efficiency
▬ High availability through design
of all components specially for
rolling mills
▬ High flexibility
▬ Complete transparency
of material flow
▬ Reduction of coil damage
to virtually zero
▬ High profitability of overall
system
15
MEETING your EXPECTATIONS
SIEMAG GMBH
Wiesenstrasse 30
57271 Hilchenbach, Germany
Walder Strasse 51 – 53
40724 Hilden, Germany
Obere Industriestrasse 8
57250 Netphen, Germany
Phone: +49 (0) 2733 29-1800
Telefax: +49 (0) 2733 29-1782
Phone: +49 (0) 211 881-5100
Telefax: +49 (0) 211 881-5200
Phone: +49 (0) 2738 21-521
Telefax: +49 (0) 2738 21-591
E-mail: cold.mills@
sms-demag.com
Internet: www.sms-demag.com
E-mail: strip.processing@
sms-demag.com
Internet: www.sms-demag.com
E-mail: [email protected]
Internet: www.siemag.com
METEC 2007 · Session 3 E
250/05/07 . WW . Printed in Germany
SMS DEMAG AG