COR-TEN™

Plate
COR-TEN
™
http://www.nssmc.com/
2-6-1 Marunouchi, Chiyoda-ku,Tokyo 100-8071 Japan
Tel: +81-3-6867-4111
COR-TENTM
A006en_02_201404f
© 2008, 2014 NIPPON STEEL & SUMITOMO METAL CORPORATION
™
Susa Bridge (Yamaguchi)
Photo: 1992 (3 years after completion)
™
is a registered trade name of United States Steel Corporation.
Contents
1
̶
̶̶̶̶̶̶̶̶̶̶̶̶̶̶ 2
Saving Maintenance Cost ̶̶
2
Features ̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶ 3
3
̶
̶
̶
̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶ 4
Weather Resistance ̶
̶̶̶̶̶̶̶̶̶̶̶̶̶̶ 5
●Exposure Test Results ̶̶̶̶
●Secular Changes in Rust Appearance ̶̶̶̶̶̶̶̶̶ 5
4
Application Examples ̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶ 6
5
Specification ̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶ 14
●Unpainted use (Bare) ̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶ 6
̶8
●Unpainted use (Complementary Rust Stabilization Treatment) ̶
●Painted use ̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶ 10
●CORQ™ (Cast Metal) ̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶ 12
●Various Application Examples ̶̶̶̶̶̶̶̶̶̶̶̶ 13
●Steel Grades and Features ̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶ 14
●Chemical Composition ̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶ 15
●Mechanical Properties ̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶ 16
6
Available Size ̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶ 18
7
Characteristic Properties ̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶ 21
●Abrasion Resistance ̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶ 26
●Weldability ̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶ 27
●Weld Joint Properties ̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶ 28
●Workability ̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶ 29
●Plate (As Roll) ̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶ 18
●Plate (Heat Treatment) ̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶ 19
●Hot-rolled Sheet ̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶ 20
●Cold-rolled Sheet ̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶ 20
●Physical Properties ̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶ 21
●Chemical Composition ̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶ 22
●Mechanical Properties ̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶ 22
●Paint durability ̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶ 24
●Paint Film Deterioration Tests ̶̶̶̶̶̶̶̶̶̶̶̶̶ 25
●Impact Properties ̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶ 26
8
Joint Materials ̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶ 30
●Welding Materials ̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶ 30
●Bolt Joints ̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶̶ 31
Notice:
While every effort has been made to ensure the accuracy of the information contained within this publication, the use of the information is at the reader’s risk and no warranty is
implied or expressed by Nippon Steel & Sumitomo Metal Corporation with respect to the use of the information contained herein. The information in this publication is subject to
change or modification without notice. Please contact the Nippon Steel & Sumitomo Metal Corporation office for the latest information. The names of our products and services
shown in this publication are trademarks or registered trademarks of Nippon Steel & Sumitomo Metal Corporation, affiliated companies, or third parties granting rights to Nippon
Steel & Sumitomo Metal Corporation or affiliated companies. Other product or service names shown may be trademarks or registered trademarks of their respective owners.
1
Saving Maintenance Cost
Since 1959 when COR-TEN began to be marketed, this
material has served as served as weathering steel
(atmospheric corrosion-resistant steel).
COR-TEN has successfully overcome rust, steel’s
most weakest, by capitalizing on its unique “rust cures
rust” function.
When exposed to the atmosphere without painting,
COR-TEN begins to rust in the same way as ordinary
steel. But soon the alloying elements in COR-TEN cause
a protective surface layer of fine-textured rust to form,
thereby suppressing corrosion rate.
Capitalizing on this excellent property, COR-TEN
can be used without painting, thereby nullifying the
commonly held belief that “steel must be used with
paint.”
But, if paint is applied to COR-TEN, the service life of
the paint is prolonged compared to coatings applied to
ordinary steel. Accordingly repainting costs are reduced.
Since its development in the U.S. in 1933,
COR-TEN has been used in every field where steel is
applied, such as bridges, railway vehicle and buildings.
Recently, unpainted applications of COR-TEN are
attracting attention as being especially suited for
resource savings and environmental concerns.
Another growing application of unpainted COR-TEN
is in conjunction with rust stabilization treatments on
bridges, building exteriors and other structures.
In this way, COR-TEN helps to reduce lifecycle
costs (LCC) and environmental burdens in a wide range
of applications.
2
Features
Weather Resistance
Because COR-TEN has high weather resistance, it can be used
without painting. Unpainted applications not only offer the
economic advantage of reducing repainting costs; they also offer
aesthetic benefits associated with the calming color of the
protective rust.
While weather resistance depends on the product grade and
the application environment, COR-TEN’s weather resistance is
nearly 4~8 times that of ordinary steel.
Paint durability
COR-TEN is paintable in the same way as ordinary steel. In
addition, even if a painting defect should occur, COR-TEN
suppresses the progress of rust area and, accordingly, prolongs
the service life of the paint, thereby reducing repainting costs.
Weldability
While trace amounts of alloying elements such as copper (Cu)
and chromate (Cr) are added to COR-TEN to ensure high
weather resistance, the carbon content is lowered to provide
appropriate weldability. Accordingly, COR-TEN can be welded
using either manual, gas-shield or submerged arc welding. In
addition, spot welding can be applied to thin-gauge COR-TEN.
Workability
COR-TEN possesses workability (cold forming, hot forming and
gas cutting) similar to ordinary steels of same strength.
Reliability
Since 1959 when “COR-TEN” began to be marketed, more than
2.6 million tons of this material have been produced. (2013 end)
2
3
3
Weather Resistance
When COR-TEN is exposed to the atmosphere, it
develops an initial layer of rust as ordinary steel does.
But, as time goes by, this early product gradually
converts to a fine-textured rust (protective rust) that
tightly adheres to the base metal, providing a protective
layer that both protects the base metal and suppresses
further corrosion.
F i g . 1 s h o w s t h e re s u l t s o f e x p o s u re t e s t s
conducted in an industrial area. It can be seen from the
figure that corrosion in COR-TEN is suppressed within 3
to 5 years.
Fig. 2 shows the results of exposure tests in
coastal areas. As can be seen in the figure, while the
corrosion level of COR-TEN is lower progress than that
of ordinary steel, corrosion continues to develop in
COR-TEN for a long period. Accordingly, it is necessary
to pay due care in the application of COR-TEN in coastal
areas.
Fig. 3 shows the results of exposure tests in the
U.S. The corrosion in both Japan and the U.S. show the
same trend, but the corrosion levels in the U.S. is only
about 1/3 to 1/2 that in Japan. This seems attributable
to differences in temperature and humidity between
Japan and the U.S.
Fig. 1 Exposure Tests in Industrial Areas
Corrosion
腐食量loss (mm)
Tobata
Corrosion
腐食量loss (mm)
Amagasaki
Exposure
曝露年数years
■Exposure Test Results
Because a reliable accelerated test method is not
available and because the alloying elements used in
steel products and the effects of individual application
environments are complicated, it is necessary to carry
out long-term exposure tests using numerous test
specimens in order to judge whether weather resistance
is high or low.
COR-TEN was developed in 1933 as a result of
long-term exposure tests using 30,000 or more test
specimens. Since then, exposure tests and follow-up
surveys of existing structures have been continued
worldwide to further improve weather resistance.
Extensive knowledge has been obtained on the
performance characteristics that weathering steel
should possess and on the environmental conditions
required for weathering steel to fully demonstrate its
unique weather resistance. The following offers a
summary introduction of such knowledge.
Exposure Tests (without eaves)
Exposure
曝露年数years
Fig. 2 Exposure Tests in Coastal Areas
Ashizuri-misaki
It is necessary for weathering steel to be
subjected to repeated wet-dry cycles in the
atmosphere in order to form protective rust
Accordingly, when the surfaces of weathering steel are
constantly submersed in water or wet earth, protective
rust does not form. Consequently, the application
environment such as this prevent the peculiar features
of weathering steel from being fully utilized.
Further, protective rust is most likely to form in
sections subjected to sunlight and rainfall, but is less
likely to form in areas subjected to salts.
Because these environmental effects become
clear when steel products are exposed to the
atmosphere in an as-rolled state, it is necessary in
unpainted applications of weathering steel to pay full
attention not only to the select of COR-TEN steel but
also to the purpose of its use and to the site where it is
to be used.
Corrosion
腐食量loss (mm)
Corrosion
腐食量 loss (mm)
Secular Changes in Rust Appearance
Fig. 3-2 Exposure Tests in Coastal Areas in U.S.
腐食量 loss (mm)
Corrosion
Keanmy N. J.
曝露年数 years
Exposure
In the initial stage of application, COR-TEN shows a yellowish appearance. This is followed by a gradual change
in the color of the protective rust from brown to a stable dark brown after one to two years in general application
environments. Afterwards, the coloration shows no clear change except perhaps to a deeper dark brown.
Exposure
曝露年数 years
Fig. 3-1 Exposure Tests in Industrial Areas in U.S.
Corrosion
腐食量 loss (mm)
As regards weather-resistant alloying elements, P, Cu, Cr
and Ni are widely known. Further, Si, Mo, Ti and V are
known as complementary elements used to improve
weather resistance in combination with Cu and Cr.
Further, a multiplier effect can be obtained by
appropriately combing the use of these elements, and
thus higher weather resistance can be obtained by
finding the optimum mix of elements from many
experiments.
Sakaide Port (wharf) Weld joining material
(Use of welding material exclusively used for SAW)
Exposure
曝露年数 years
4
It is necessary that steel products include the
weather-resistant elements that which contribute
to the formation of protective rust
Kure Beach N.C. (The point 200 m from open sea)
(No exposure
after 8 years)
A36
（以後曝露せず）
（t×50×150mm）
曝露年数years
Exposure
0.5 months
1.5 months
6 months
2 years
5 years
22 years
40 years
5
4
Application Examples
Unpainted use (Bare)
The unpainted application of COR-TEN not
only offers economical advantages but,
thanks to the calming color of the
protective rust, it also demonstrates
excellent aesthetic properties. Because of
this, COR-TEN is applied in a wide range
of fields such as buildings and monuments.
Because the initial outflow of rust dirties the
surrounding area, it is necessary to fully
examine the application site and the
purpose for using COR-TEN and to devise
a structuring method.
Kanno Museum of Art (Miyagi) Photo: May 2007 (1 year after completion)
Univ. OKAYAMA Pref. Alumni House: June 2013 (at time of completion)
N Corporation (Tokyo) Photo: Oct. 2005 (40 years after completion)
La Chapelle des Pommiers (Normandy, France; floor member; by Kyoji Takubo)
Photo 1999 (at time of completion)
Hokkaido Centennial Memorial Tower (Hokkaido)
Photo: Oct. 1969 (under construction)
Photo: Apr. 1973 (4 years after completion)
Photo: Sep. 1977 (8 years after completion)
6
Photo: May 1991 (22 years after completion)
Photo: Jul. 2010 (41 years after completion)
Shimane Museum of Ancient Izumo (Shimane) Photo: Oct. 2009 (3 years after completion)
IRONHOUSE (Tokyo) Photo: Dec. 2009 (2 years after completion)
7
4
Unpainted use (Complementary Rust Stabilization Treatment)
COR-TEN can be applied without painting (in a bare
state), thus reducing the cost of repainting and other
repairs. However, there have been expressions of
concern during the first year or two when the protective
layer of fine-textured rust (protective layer) is forming.
These concerns usually referred to adverse landscaping
associated with the yellowish color of the initial rust and
to the contamination of surrounding areas caused by the
runoff of early-stage rust washed away by rainwater. As
a result, there have been obstacles linked to the use of
COR-TEN in spite of its superior economic advantages.
In order to solve these problems, supplementary
rust stabilization treatment was developed.
In the case of Complementary Rust Stabilization
Treatment, agents similar in color to rust have been
selected on the premise that the agents would be
converted to rust in the future. Recently, in order to meet
requests for the free selection of colors that harmonize
with surrounding colors, Complementary Rust Stabilization
Treatment agents to which various colors can be applied.
Because the Complementary Rust Stabilization
Treatment agents will eventually be converted to rust, there
is a certain period when the color will cease, over time, to
remain uniform. When countermeasures are required from
a landscaping perspective, it is necessary to apply an easy
restoration treatment for surface layer film.
Ariake-tennis-no-mori (Tokyo) Photo: May 2007 (20 years after completion)
Nagaragawa Baseball Stadium (Gifu) Photo: Oct. 2011 (22 years after completion)
Asunaro Bridge (Aomori) Photo: 1990 (completion)
Viaduct Hokuriku Super-express (Niigata) Photo: Jun. 2005 (5 years after completion)
Arakawa Bridge (Tokyo): Landscape type Complementary Rust Stabilization
Treatment (light blue) Photo: Jul. 2007 (6 years after completion)
World Hall (Hyogo) Photo: Mar. 2010 (26 years after completion)
Steel pier of Kitasaki Viaduct (Aichi): Landscape type Complementary Rust
Stabilization Treatment (white) Photo: Jul. 2007 (7 years after completion)
Nagano Municipal Museum of Art (Nagano) Photo: Aug. 1980 (8 months after completion)
Nagano Municipal Museum of Art (Nagano) Photo: Jul. 2006 (27 years after completion)
8
9
4
Painted use
When COR-TEN is painted, the required number of times
that repainting must be conducted can be reduced.
This advantage is believed to result from the fact
that, even when corrosion occurs in the base metal due
to defects in the painted film or to pinholes, the
corrosion progresses slowly and thus the occurrence of
blistering and peeling of the paint film is reduced.
By making the most of this advantage, COR-TEN is
applied in every field where steel is used̶ranging from
buildings to railway vehicle, marine containers, storage
tanks, industrial machinery and bridges.
Arakawa Bridge (Tokyo)
High-speed passenger ship (Setouchi Sea Line)
Flying Dome of Nihondaira Zoo (Shizuoka) Photo: Mar. 2011 (under constuction)
Onomichi Bridge (Hiroshima) Photo: 1968 (under construction)
Jinbocho Theater (Tokyo) Photo: Dec. 2007 (0.5 years after completion)
Unloading equipment
Container
10
Former Nippon Steel Head Office (Tokyo) Photo: Oct. 2009 (40 years after completion)
Freight train
Concrete mixer car
LANVIN (Tokyo) Photo: Jan. 2010 (6 years after completion)
Gosha Inari Shrine (Aichi) Photo: Oct. 2005 (completion)
11
4
CORQ™ (Cast Metal)
Various Application Examples
CORQ™ is a registered trade name of Kyoji Takubo and Nippon Steel & Sumitomo Metal Corporation.
CORQ is a cast metal product that has the features of
COR-TEN and is used mainly for floor materials.
CORQ is produced and marketed by Okayama
Casting Center (Tel: 8-86-277-5588).
Yokohama Naka Ward Office (Kanagawa)
Photo: Oct. 2006 (23 years after completion)
Kamitsubaki (Kagawa) Photo: Nov. 2007 (completion)
Northern goshawk protection shelter at Ken-O
Expressway (Saitama) Photo: Mar. 2008
(completion)
Kamitsubaki (Kagawa) Photo: Nov. 2007 (completion)
“Stair in the Void” by Minoru Togashi (Yamagata)
Photo: Jun. 2005 (4 years after completion)
Library of Rikuzen Takada city “place of recreation” Photo: Sep. 2013 (completion)
Application of CORQ in floor
Example of CORQ application
“Tamasora” by Noe Aoki Photo: Tadasu Yamamoto
Entrance of company dormitory Photo: Jun. 2013 (completion)
12
Higashiyama water supply tower (Aichi)
Photo: May 1983 (completion)
Higashinihonbashi-Sanchyome Condominium (Tokyo)
Photo: May 2005 (completion)
Parts of CORQ
13
Designation
Highly weathering steel product COR-TEN O
Applicable thickness range (mm)
Hot-rolled sheet and plate：1.6≦t≦76
Cold-rolled sheet：0.4≦t≦2.3
Shape：6≦t≦38
Bar：5.5≦t≦44
Chemical Composition
Feature
●Because
of its high
weather
resistance,
this grade is most
suitable for unpainted
application.
●Because
Unpainted specifications
For welded structures
Weathering steel product
COR-TEN 490A/B/C
Hot-rolled sheet and plate：6≦t≦50
Shape：6≦t≦38
COR-TEN 570
Hot-rolled sheet and plate：6≦t≦50
NAW™ 400
Hot-rolled sheet and plate：1.6≦t≦12.7
Shape：3.2≦t≦12.7
NAW™ 490
Hot-rolled sheet and plate：1.6≦t≦12.7
Cold-rolled sheet：0.4≦t≦2.3
Shape：3.2≦t≦12.7
General weathering steel product
NAW -TEN™12
-400A/B/C
-490A/B/C
-570
Ni-type highly weathering
steel product
NAW -TEN™15
-400A/B/C
-490A/B/C
-570
Hot-rolled sheet and plate：6≦t≦100
Highly weathering steel product COR-TEN A
COR-TEN B
Unpainted specifications
For welded structures
COR-TEN B-QT
Weathering steel product
COR-TEN C
t≦12.7
Hot-rolled
sheet and
plate
t≦200
t≦100
t≦25
Main applications
panel and other
building exterior members
●Outer plate for rolling
stock
●Marine container
●Steel tower, etc
●Bridge
●Featuring
economical
advantage, this grade is
recommended for use
with painting.
●Because of its high
strength, NAW 490
offers a high wet
abrasion resistance.
●Column,
●Because
of its high
weather resistance, this
grade is most suitable
for unpainted use.
●Because of its high
weldability and notch
toughness, this grade is
recommended for use
for welded structures.
●The mechanical properties excluding
chemical composition conform to
those in JIS SMA standards.
●Bridge
●Because
●Sash,
●Because
of its high weather
resistant, this grade can be
used without painting.
●Because of its high
weldability and notch
toughness, this grade is
recommended for use
for welded structures.
●Steel
frame, steel tower,
various platforms
●Crane
and
other
industrial machinery
●Flood gate
●Low-pressure gas holder,
water tank and other
large-size vessels
Designation
Highly weathering steel product COR-TEN O
beam and
outer plate of container
●Ready-mixed concrete
car
●Small-capacity compressor
tank
●Steel
frame, steel tower,
various platforms
●Crane
and
other
industrial machinery
●Flood gate
●Low-pressure gas holder,
water tank and other
large-size vessels
P
S
Cu
Ni
Cr
0.07
0.20
0.30
≦0.12 0.25
≦0.035 0.25
≦0.65
～0.55
～0.75 ～0.50 ～0.15
～1.25
Other elements
─
value
─
≦0.17
V:0.02
0.30
0.40
0.80
0.45
0.05
≦0.035 ≦0.035
～0.40 ～0.30 ～0.65 ～0.10
～0.65 ～1.25
─
NAW™ 490
─
─
COR-TEN B
Unpainted specifications
COR-TEN B-QT
For welded structures
Weathering steel product
COR-TEN C
≦0.150 ≦0.050
≦1.25
≦0.18
-490A/B/C
-570
COR-TEN A
─
0.20
～0.40
0.06
0.25
≦0.12 0.15
≦0.90 ～0.12 ≦0.035 ～0.50
～0.35
NAW -TEN12
-400A/B/C
Highly weathering steel product
Mn
─
NAW™ 400
General weathering
steel product
Si
V:0.02
0.30
0.30
0.80
0.45
0.05
≦0.035 ≦0.035
～0.40 ～0.30 ～0.65 ～0.10
～0.65 ～1.25
Ni-type
highly
-490A/B/C
-570
weathering steel
Highly weathering
NAW -TEN15
steel product
-400A/B/C
●Bridge
C
COR-TEN 490A/B/C ≦0.17
COR-TEN 570
tower
●Building exterior member
panel and other
building exterior members
●Outer plate for rolling
stock
●Marine container
●Steel tower, etc
Chemical Composition
（%）
Unpainted specifications
For welded structures
Weathering steel product
●Steel
Notes:
1) For unpainted uses, COR-TEN O, COR-TEN 490, COR-TEN 570, NAW-TEN™ 12 and NAW-TEN™ 15 are applied.
2) Thicknesses or diameters other than those listed in the above table are subject to the agreement between the orderer and us.
3) Bar includes bar-in-coil. But the diameter of bar-in-coil should be 32 mm or less.
4) Regarding the grade other than those shown above, equivalent grades can be manufactured. Please consult us in advance.
5) NAW™ and NAW-TEN™ are a registered trade name of Nippon Steel & Sumitomo Metal Corporation.
6) Shapes are constantly not manufactured, so please consult us in advance concerning designations (only A and B) and size selection.
14
Steel grade
●Sash,
of its high
weather resistance, this
grade can be used
without painting.
●Because of its high
weldability and notch
toughness, this grade is
recommended for use
for welded structures.
of its high
weather resistance,
this grade is most
suitable for unpainted
application.
Destination
For domestic uses
Steel grade
Steel Grades and Features
For overseas uses
5
Specification
0.15
～
0.65
─
≦0.40
─
─
─
─
≦Ti:0.15
─
≦1.40
≦0.035 ≦0.035
≦1.25
≦1.40
─
0.50
0.70
～
～
1.00
1.70
≦1.20
─
≦0.08
0.30
2.50
～
～
0.50
3.50
0.20
0.07
≦0.65 0.50
≦0.12 0.25
≦0.05 0.25
～0.55
～1.25
～0.75 ～0.50 ～0.15
≦0.19
≦0.19
─
≦1.50
─
─
0.25
0.40
0.30
0.80
V:0.02
～0.65 ～1.25 ≦0.04 ≦0.05 ～0.40 ≦0.40 ～0.65 ～0.10
─
─
0.25
0.30
0.80
V:0.04
≦0.40 0.40
≦0.04 ≦0.05
～0.40
～0.65 ～1.35
～0.70 ～0.10
Notes:
A parameter to weather-resistant alloying elements (ν value) is given by the following equation. Unit: mass%
ν value=1/
｛（1.0－0.16［ C］）
×
（1.05－0.05［ Si］）
×
（1.04－0.016［ Mn］）
×
（1.0－0.5［ P］）
×
（1.0＋1.9［ S］）
×
（1.0－0.10［ Cu］）
×
（1.0－0.12［ Ni］）
×
（1.0－0.3
［Mo］
）
×
（1.0－1.7
［Ti］
）｝
C. Miki, A. Ichikawa, M. Ukai, S. Takemura, T. Nakayama and H. Kihira: Proposal of Weather-resistant Alloying Parameters and Weather
Resistance Assessment Methods, Journal of Japan Society of Civil Engineers, No. 738/1-64, pp 271-281, July 2003
15
5
Mechanical Properties
＊Bending test
（180°
bending）
Tension test
Designation
Product
Cold-rolled sheet
COR-TEN O
Hot-rolled sheet and plate
Shape
Bar
Bar-in-coil
COR-TEN 490 A/B/C
COR-TEN 570
NAW 400
NAW 490
NAW-TEN12-400 A/B/C
NAW-TEN15-400 A/B/C
NAW-TEN12-490 A/B/C
NAW-TEN15-490 A/B/C
NAW-TEN12-570
NAW-TEN15-570
Hot-rolled sheet and plate
Shape
Hot-rolled sheet and plate
Hot-rolled sheet and plate
Shape
Cold-rolled sheet
Hot-rolled sheet and plate
Shape
Hot-rolled sheet and plate
Hot-rolled sheet and plate
Hot-rolled sheet and plate
COR-TEN A
COR-TEN B
Hot-rolled sheet and plate
COR-TEN B-QT
COR-TEN C
16
Elongation
Tensile strength
N/mm2
Thickness or diameter mm Elongation %
Test piece
JIS
Thickness or diameter
mm
Inner radius
Test piece
JIS
Symbol
─
t≦5
5＜t≦16
24≦
22≦
18≦
No.5
No.5
─
t≦5
─
1.0t
─
No.3
─
─
─
─
─
─
─
─
16＜t≦38
21≦
5＜t
1.0t
No.1
─
─
─
─
D≦32
32＜D
1.5D
2.0D
No.2
─
─
─
─
─
─
─
─
─
─
─
B
0
27≦
C
0
47≦
Thickness or diameter
mm
Yield point
N/mm2
t≦2.3
315≦
450≦
t≦20
355≦
490≦
20＜t≦38
325≦
＊＊Impact test
460≦
No.1A
No.4
No.2
No.3
38＜t
295≦
430≦
38＜t
D≦38
38＜D
t≦16
16＜t≦40
40＜t
t≦16
16＜t≦40
40＜t
325≦
295≦
360≦
355≦
335≦
460≦
450≦
430≦
460≦
430≦
─
245≦
400～510
─
345≦
460≦
─
390≦
490≦
t≦16
16＜t≦40
40＜t≦100
t≦16
16＜t≦40
40＜t≦75
75＜t≦100
t≦16
16＜t≦40
40＜t≦75
75＜t≦100
245≦
235≦
215≦
365≦
355≦
335≦
325≦
460≦
450≦
430≦
420≦
D≦25
25＜D
t≦16
16＜t
40＜t
t≦16
16＜t
20＜t
t≦5
5＜t
t≦2.3
t＜6
6≦t
t≦16
16＜t
40＜t≦100
t≦16
16＜t
40＜t≦100
21≦
No.4
t≦16
16＜t
19≦
26≦
No.5
20＜t≦100
20≦
No.4
≦12.7
345≦
485≦
345≦
485≦
100 over t≦125
125 over t≦200
≦100
315≦
290≦
485≦
460≦
435≦
620/760
≦25
415≦
550≦
22≦
18≦
21≦
18≦
21≦
21≦
19≦
21≦
16≦
＊＊＊50
≦100
─
─
─
─
─
─
─
─
─
570～720
400～540
490～610
570～720
Test piece
JIS
No.1A
21≦
23≦
20≦
23≦
15≦
19≦
21≦
19≦
26≦
20≦
21≦
17≦
22≦
22≦
23≦
17≦
21≦
23≦
15≦
19≦
490～610
Test temperature Charpy absorbed energy
J
°C
No.1A
No.4
No.5
No.4
No.5
No.1A
No.5
No.1A
─
─
─
─
－5
47≦
─
─
─
─
─
1.0t
1.5t
─
1.0t
1.5t
No.3
No.1
─
No.3
No.1
─
─
─
─
─
─
─
─
─
─
─
─
─
─
A
B
C
A
B
─
─
─
─
─
─
27≦
47≦
─
27≦
No.4
No.1A
─
─
─
C
─
─
─
─
0
─
0
－5
47≦
V-notch
Rolling direction
─
─
─
─
─
V-notch
Rolling direction
47≦
＊＊＊200
＊＊＊50
＊＊＊200
＊＊＊50
＊＊＊50
＊＊＊50
＊＊＊50
＊＊＊200
＊Can be eliminated unless otherwise orderer specifies
＊＊Applied to steel product with thicknesses more than12 mm
＊＊＊Test piece Gage length, mm
17
6
Available Size
Plate
As Roll (products other than those listed in the table on page 18)
Heat Treatment (COR-TEN 570, COR-TEN B-QT, NAW-TEN12-570, NAW-TEN15-570)
Standard available sizes
〜
〜
〜
8.0
〜
Notes:
1) The figure in the table indicates the maximum length (m) of plate.
2) The minimum length shall be 3 m.
3) Regarding the applicable plate thickness, please refer to “Specifications” on page 13.
8.5
〜
8.5
8.5
〜
8.5
8.5
〜
18.0 16.0 13.0 12.0 12.0 11.5
8.5
8.5
8.5
〜
9.0
9.0
〜
9.5
9.0
〜
20.0 17.5 14.5 13.0 13.0 12.5 11.5 11.5
9.5
〜
18.5 17.0 17.0 15.5 14.5 13.5 12.5 12.0 11.5 11.0 10.0
15.5
22.5 20.0 16.0 15.0 15.0 13.5 12.5 12.0 11.0 10.5 10.0 9.5 9.0
〜
21.5 19.5 19.5 18.0 17.0 15.5 14.5 14.0 13.0 12.5 11.5 11.5 11.0 10.5 10.0
〜
22.0
20.0
19.0
18.0
17.0
16.0
15.0
14.0
11.0
〜
21.0
20.0
19.0
18.0
17.0
16.0
12.0
22.0
21.0
19.0
18.0
17.0
16.0
15.0
14.0
11.0
〜
22.0
21.0
20.0
19.0
18.0
14.0
22.0
21.0
20.0
19.0
18.0
17.0
13.0
22.0
20.0
19.0
18.0
17.0
16.0
15.0
12.0
〜
15.0 15.0
15.0 15.0 15.0
23.0 23.0
23.0 23.0 23.0 23.0
Thickness
mm
〜
15.0 15.0 15.0 15.0 15.0 15.0 15.0 15.0 15.0 15.0 15.0 15.0
23.0 23.0 23.0 23.0 23.0 23.0 23.0 23.0 23.0 23.0 23.0
Standard available sizes
Width
1200
mm 1000 Over 1400 1600 1800 2000 2200 2400 2600 2800 3000 3200 3400 3600 3800 4000 4200 4400
〜
〜
〜
〜
〜
〜
〜
1200 1400
1600 1800 2000 2200 2400 2600 2800 3000 3200 3400 3600 3800 4000 4200 4400 4500
or less or less
15.0
6
over 6　7 incl　23.0
8
7
9
8
10
9
12
10
14
12
16
14
18
16
20
18
22
20
24
22
26
24
28
26
30
28
32
30
34
32
36
34
38
36
40
38
42
40
44
42
46
44
48
46
50
48
52
50
54
52
56
54
58
56
60
58
65
60
70
65
75
70
80
75
85
80
90
85
95 21.0
90
95 100
18
〜
〜
〜
〜
〜
〜
〜
〜
〜
〜
Thickness
mm
〜
〜
Width
1200
mm 1000 Over 1400 1600 1800 2000 2200 2400 2600 2800 3000 3200 3400 3600 3800 4000 4200 4400
1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 3200 3400 3600 3800 4000 4200 4400 4500
or less or less
6
16.0
over 6　7 incl　20.0
8 21.0
7
9
8
10
9
12
10
14
12
16 22.0
14
18
16
20
18
22
20
24
22
26
24
28
26
30
28
32
30
34
32
36
34
38
36
40
38
42
40
44
42
46
44
48
46
50
48
52 23.0
50
54
52
56
54
58
56
60
58
65
60
70
65
75
70
80
75
85 22.5
80
90
85
95 20.0
90
95 100
16.0 16.0 16.0 16.0 16.0 16.0 16.0 16.0 16.0 12.0
20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 14.0
21.0 21.0 21.0 21.0 21.0 21.0 21.0 21.0 21.0 15.0
20.0
20.0
21.0 21.0 21.0
21.0 21.0 21.0 21.0 21.0
22.0 22.0 22.0 22.0 22.0 22.0 22.0 22.0 22.0 22.0 22.0 22.0 22.0
22.0
22.0
22.0 22.0
21.0
21.0 20.0
20.0 19.0
23.0 23.0 23.0 21.5 19.5 18.0 17.0 15.5
20.0
20.0 19.0
21.0 19.0 18.0
21.0 20.0 18.0 17.0
20.0 19.0
19.0
17.0 16.0
18.0 17.0 16.0 15.0
16.0 15.0
14.5 14.0 13.0 12.5
20.0
19.0
18.0
17.0
16.0
15.0
14.0
11.5
20.5 18.5 17.0 15.5 14.5 13.5 12.5 12.0 11.5 11.0 10.0
22.5 20.0 19.0 16.0 15.0 13.5 12.5 12.0 11.0 10.5 10.0
18.0
20.0 17.5 16.0 14.5 13.0 12.5 11.5 10.5 10.0 9.5 9.0
18.0 16.0 14.5 13.0 12.0 11.0 10.5
9.5
9.0
8.5
8.0
21.0
20.0
19.0
21.0
18.0
19.0
17.0
18.0
16.0
17.0
15.0
16.0
15.0 14.0
15.0 13.0 13.0
14.0
12.0
13.0 12.0
11.5 11.0 10.5
21.0
20.0
18.0
17.0
16.0
15.0
14.0
21.0
19.0
18.0
17.0
16.0
13.0
12.0
10.0
9.5
9.0
9.0
8.5
9.5
9.0
8.5
8.0
7.5
7.5
8.5
8.0
7.5
7.0
7.0
6.5
7.5
7.0
6.5
6.5
6.0
6.0
Notes:
1) The figure in the table indicates the maximum length (m) of plate.
2) The minimum length shall be 3 m.
3) Regarding the applicable plate thickness, please refer to “Specifications” on page 13.
19
6
7
Hot-rolled Sheet and Cold-rolled Sheet
Physical Properties (Example)
Elastic Modulus (Unit:N/mm2)
Hot-rolled Sheet (COR-TEN O)
18.0×600
18
Characteristic Properties
18.0×1200
18.0×1690
18.0×600
16
15.0×1690
COR-TEN O
19.3～20.7×104
NAW 490
20.5×104
Thickness（mm）
14
2
＜20.74×104N/mm（18˚C）
＞
Coefficient of Thermal Expansion (Unit:×10-6/˚C)
12
Temperature range
(from room temperature)
10
Up to 100˚C Up to 200˚C Up to 300˚C Up to 400˚C Up to 500˚C Up to 600˚C
COR-TEN O
8
NAW 490
10.5
11.8
12.8
13.4
13.5
─
─
13.0
─
─
－6
4
Specific Heat (NAW 490)
3.2×600
2
1.2×600
600
1.2×1350
800
1000
1200
1400
3.2×1690
Temperature（˚C） 50
2.0×1690
Specific heat 0.105 0.111 0.122 0.105 0.128 0.134 0.140 0.145 0.150 0.164 0.176 0.198
1.4×1600
1600
1800
2000
2200
Width（mm）
3.0
2.8
Thickness（mm）
2.3×615
250
300
350
400
450
500
550
600
＜0.1136～0.1146
（20˚C）
＞
Thermal Conductivity (NAW 490)
kcal/m hr˚C
cal/cm sec˚C
－1
48.2
200
－1
1.18×10
42.5
300
1.05×10－1
37.8
400
0.94×10－1
33.8
500
－1
31.0
－1
28.8
1.34×10
0.86×10
0.80×10
＜43～52kcal/m hr˚C
（20˚C）
＞
2.3×1275
Electrical Resistance (NAW 490)
2.2
2.0
Temperature
（˚C）
1.8
20
Resistivity
（μΩ cm） 20.3
1.6
100
200
300
400
500
600
23.8
29.4
38.5
50.4
63.6
79.2
＜13.7～15.8μΩ cm
（20˚C）
＞
1.4
＜ ＞: Value of “mild steel (C: 0.12~0.20%) specified in
1.2
Handbook on Mechanical Engineering (The Japan Society
of Mechanical Engineers)
1.0
0.8×1260
0.8
0.8×1275
0.6×1250 0.6×1260
0.5×1200
0.4×1200
0.6
0
500
200
600
2.6
0.2
150
100
Cold-rolled Sheet
0.4
100
Temperature
（˚C）
Legend:
Black figure: Available size range of hot-rolled coil
Blue figure: HCL available size range (available length: 1800~12700 mm)
※The available size range differs depending on the steel grade and size. Please inquire us for every lot of orders.
2.4
13.8
＜11.16～11.28×10 / ˚C
（20˚C）
＞
6
0
400
13.6
0.4×615
700
900
1100
1300
1500
1700
1900
Width（mm）
20
21
7
Chemical Composition, Mechanical Properties (Example)
Chemical Composition and Tensile Test Values
Chemical composition
（％）
COR-TEN O
COR-TEN 490
COR-TEN 570
Product
C
Si
Mn
P
S
Cu
Ni
Cr
V
Ti
Yield point
N/mm2
Tensile strength
N/mm2
Elongation
％
Test piece
JIS
Cold-rolled sheet
1.2
0.08
0.45
0.38
0.115
0.018
0.28
0.12
0.60
─
─
345
500
33
No.5
3.2
0.08
0.43
0.40
0.094
0.005
0.28
0.17
0.59
─
─
404
536
35
No.5
6.0
0.08
0.43
0.41
0.096
0.005
0.28
0.17
0.59
─
─
392
524
27
No.1A
9.0
0.08
0.44
0.41
0.095
0.004
0.28
0.16
0.61
─
─
382
520
26
No.1A
12
0.13
0.26
1.01
0.008
0.006
0.32
0.11
0.46
0.03
─
395
530
26
No.1A
25
0.15
0.45
0.96
0.019
0.005
0.33
0.12
0.47
0.06
─
385
520
27
No.1A
42
0.15
0.46
0.96
0.018
0.005
0.32
0.11
0.46
0.06
─
385
520
33
No.4
19
0.09
0.35
1.21
0.016
0.006
0.32
0.12
0.50
0.04
─
570
661
36
No.5
25
0.09
0.36
1.19
0.015
0.005
0.33
0.13
0.53
0.04
─
540
640
28
No.4
32
0.09
0.35
1.22
0.014
0.004
0.34
0.12
0.52
0.03
─
540
640
27
No.4
2.0
0.07
0.18
0.55
0.043
0.018
0.28
─
0.35
─
─
305
450
36
No.5
0.08
0.20
0.62
0.066
0.004
0.27
─
─
─
432
547
31
No.5
─
─
─
433
535
34
No.5
Hot-rolled sheet and plate
Hot-rolled sheet and plate
Hot-rolled sheet and plate
NAW 400
Hot-rolled sheet and plate
NAW 490
Hot-rolled sheet and plate
2.3
8.0
High-temperature Tension Test Results
Stress
Maximum cyclic stress
Fatigue Test Results
●Loading type: Pulsating tension
●Minimum load: 20N/mm2
●Frequency: 500c.p.m.
●Test piece condition: As black scaled
Cyclic numbers up to fracture
22
0.03
Creep Rupture Strength (105 hours, estimated)
Stress
Designation
Tensile test value
Thickness
mm
Tensile
strength
Test temperature
0.2% offset
yield strength
Temperature
23
7
Paint durability (Example)
■Corrosion Tests for CORTEN below Paint Film
COR-TEN, ordinary carbon steel and
0.2% Cu steel were painted and
exposed to the atmosphere for one
year. The results of tests comparing
the corrosion rates of the metal
beneath the respective paint films are
shown in the table at the right.
In the test, the surfaces were
prepared with a phosphate treatment,
given a primer undercoat, and were
top-coated using an urea-type alkyd
coating. Following this, the identical
test specimens were given the same
flaw, a diagonal break in the paint
film, after which they were exposed to
the atmosphere. Photos at right show
the test conditions in the 8th month. It
is clear from the test results that
COR-TEN exhibits high performances
in every coating condition, and that,
the corrosion rate of COR-TEN is 5
times good on than that of 0.2% Cu
steel and 70 times good than that of
ordinary carbon steel.
Corrosion Test Results (Kure Beach N.C. 180 ft site, 365 days)
Atmospheric exposure tests were
conducted in Amagasaki and Himeji
(Hirohata) on test specimens that
were given three layers of zinc oxide
paint over a wash primer and then
given an artificial flaw. The test results
are shown in the photos at right.
It is understood from the photos
that there is a great difference
between COR-TEN and ordinary steel
vis-à-vis rust originating from an
artificial flaw.
Magnification
Ordinary steel
COR-TEN
Bare material
212
13
16
Direct painting on substrate surface
55
1
55
X marking on the above surface
97
1
97
Painting after phosphate treatment
26
0.3
87
X marking on the above painting
40
0.3
133
Only primer coating on substrate surface
210
7
30
Primer coating after phosphate pretreatment
133
6
22
●Ordinary steel
Using COR-TEN O, Cu-containing steel and ordinary carbon steel in industrial, semi-rural and coastal areas, H.R. Copson
and C.P. Larrabee jointly surveyed paint deterioration and corrosion rates over an 8- year span. The results of the survey
are shown below. The test results show that the higher the corrosion resistance of the steel grade, the longer the service
life of the paint film. The service life of paint applied to COR-TEN is expected to be 1.5 times (2 times on average) greater
than for other steel materials.
Chemical Composition
●0.2%Cu steel
●COR-TEN
Chemical Composition
（%）
Steel grade
Carbon steel
Cu-containing steel
COR-TEN O
No Phosphate Treatment
C
Si
Mn
P
S
Cu
Ni
Cr
Cold-rolled sheet
0.03
0.003
0.27
0.009
0.020
0.03
0.02
0.02
Hot-rolled sheet and plate
0.17
0.027
0.40
0.013
0.034
0.04
0.02
0.05
Cold-rolled sheet
0.05
0.003
0.40
0.004
0.016
0.28
0.07
0.03
Hot-rolled sheet and plate
0.16
0.016
0.25
0.006
0.024
0.21
0.04
0.02
Cold-rolled sheet
0.08
0.65
0.30
0.09
0.020
0.41
0.48
0.85
Hot-rolled sheet and plate
0.09
0.60
0.37
0.10
0.022
0.37
0.46
0.92
Corrosion Test Results for Painted Test Pieces: Number of Years of Paint Deteriorationb)
Kearny, New Jersey
(Industrial area)
Steel grade By rolling
Bonderizing Primer
●0.2%Cu steel
●COR-TEN
●4-year exposure (Amagasaki)
RedZinc
Iron
RedZinc
Iron
RedZinc
Iron
lead
chromate
lead
chromate
lead
chromate
oxide
oxide
oxide
primer coating primer coating primer coating primer coating primer coating primer coating primer coating primer coating primer coating
3.0
2.0
2.5
2.0
3.0
2.0
4.0
c）
4.0
Cu-containing steel Hot rolling
4.0
4.5
5.0
5.0
8.0
2.0
5.0
c）
5.0
COR-TEN O
4.5
4.5
c）
c）
c）
c）
6.5
c）
c）
Carbon steel
Cu-containing steel Cold rolling
2
2
c）
c）
c）
c）
d）
c）
d）
c）
c）
c）
c）
c）
c）
d）
c）
d）
COR-TEN O
c）
c）
c）
c）
c）
c）
d）
c）
d）
Kearny, New Jersey
(Industrial area)
●8-year exposure (Hirohata)
Kure Beach, North Carolina
(Coastal area, 800 ft from sea)a)
RedZinc
Zinc
RedZinc
Iron
RedZinc
Iron
lead
chromate
lead
chromate
lead
chromate
oxide
oxide
oxide
primer coating primer coating primer coating primer coating primer coating primer coating primer coating primer coating primer coating
90
50
100
90
25
99
60
Trace
100
50
13
90
10
3
10
30
Trace
50
COR-TEN O
10
3
1
Trace
Trace
0
Trace
Trace
Trace
Carbon steel
25
50
98
0.3
0
0.1
0d）
0
100
Trace
0
Trace
0.1
0
Trace
0
d）
0
80
0
0
0
0
Trace
0
0d）
0
0d）
COR-TEN O
COR-TEN 490
South Bend, Pennsylvania
(Semi-rural area)
Carbon steel
Cu-containing steel Hot rolling
Cu-containing steel Cold rolling
SS 400
Kure Beach, North Carolina
(Coastal area, 800 ft from sea)a)
Carbon steel
Steel grade By rolling
COR-TEN 490
South Bend, Pennsylvania
(Semi-rural area)
Corrosion Test Results for Painted Test Pieces: Rust Occurrence Rate after Lapse of 8 Years
Exposure Test Results for Painted Steel Pieces
SS 400
24
Corrosion rate mg/100cm2/day
Painting condition
●Ordinary steel
■Exposure Tests for Painted
Materials in Industrial Areas
Paint Film Deterioration Tests (Example)
Notes:
a) The test piece of cold-rolled carbon steel caused corrosion from its rear side, and pitting occurred in 8 years, leading to nearly damage.
b) When the breach of paint coatings occurs on the 2% of the sheet surface, including the cut edges, it is defined as deterioration of painting.
c) Paint breach: Less than 2% even when 8 years have passed
d) Rust below paint film caused discoloration, and the film was not breached.
25
Impact Properties and Abrasion Resistance (Example)
Steels containing P─such as
COR-TEN O, NAW 400 and NAW
490－are likely to suffer hot cracking
during welding and are thus not
recommended for use in welded
structures requiring heavy-gauge
members that are ≧13 mm in
thickness.
For welded structure applications, it is recommended to adopt
NAW K-400, COR-TEN 490 and
COR-TEN 570 having high weldability. These products are low in
hardenability, highly resistant to
weld cracking and offer high joint
performance.
Impact Properties
Absorbed energy
（J）
Brittle fracture ratio（%）
Charpy Transition Curve (V-notch (Sub-size test piece 5×10 mm in plate thickness of 6 mm))
Test temperature（˚C）
（Plate thickness）
COR-TEN O
（6mm）
NAW490
（6mm）
COR-TEN 490
（20mm）
Weldability (Example)
COR-TEN570
（20mm）
L-direction
Taper Hardness Test Results
Welding direction
Arc strike
Plate thickness
（mm）
Plate thickness
（mm）
Arc strike
Hardness of heat-affected zone
7
Cooling rate at 540˚C
（˚C/sec）
Cooling time from 800˚C to 500˚C
（sec）
C-direction
Abrasion Resistance
Abrasion Resistance to Wet Sand
Y-groove Weld Cracking Test Results (COR-TEN 490)
Plate thickness : 38mm
Abrasion loss
Root cracking
Section cracking
Surface cracking
Crack occurrence ratio
（%）
Crack occurrence ratio
（%）
Plate thickness : 19mm
Initial temperature of plate
（˚C）
Initial temperature of plate
（˚C）
Plate thickness : 42mm
Crack occurrence ratio
（%）
（　）
: HB hardness
Test piece　10φ×120mm
Revolution rotation number　1,000/hr
Revolution radius
180mm
Autorotation number 5,000/hr
Crack occurrence ratio
（%）
Plate thickness : 32mm
Number of rotation
（　×104）
Initial temperature of plate
（˚C）
26
Initial temperature of plate
（˚C）
27
7
Weld Joint Properties (Example)
Workability (Example)
■Cold Bending
Weld Joint Hardness Distribution
■COR-TEN 490 (25mm) (SMAW, As-welded)
●Welding rod : CT-16 4mmφ
●Current : 160～240Amp
●Voltage : 26～33Volt
●Welding speed : 10～30cm/min
●Initial temperature of plate:
Room temperature
HAZ
HAZ
Weld metal
Base metal
●Welding material : CT-350×Y-D
●Current : 800A
●Voltage : 33V
●Welding speed : 28cm/min
●Initial temperature of plate:
Room temperature
Measurement
line
Vickers hardness
（Hv10kg）
Vickers hardness
（Hv10kg）
Measurement
line
Base metal
■COR-TEN 490 (25mm) (SAW, As-welded)
HAZ
Base
metal
HAZ
Weld metal
Base
metal
It is considered that thin-gauge plates of COR-TEN O and
NAW 490 are most commonly used with cold bending.
When cold bending is applied under the conditions
shown in the table below, favorable results can be
obtained. Meanwhile, in cases when the plate thickness
over 12 mm, it is recommended that hot working be used.
Plate thickness
Inner bending radius
≦1.6
1t
over 1.6, ≦6.0
2t
over 6.0, ≦20
3t
■Drilling and Machining
Center
Center
When drilling and machining COR-TEN 490 and
COR-TEN 590, tool damage is reduced and fine finishes
are made possible using fabrication speeds slightly lower
than those for SM490 and SM570. The standard
applicable fabrication speeds are 2/3 the speed used with
SS400 for drilling and 3/7 the speed for machining.
■Hot Working
Charpy Impact Test Results for Weld Joint of COR-TEN 490
HAZ
■Submerged arc weld joint (25mm)
●Preheating temperature :
Room temperature
Interpass temperature : 150˚C
●Welding rod : CT-350×Y-D
（4.8φ）
●Current : 800A
●Voltage : 33V
●Welding speed : 28cm/min
Both shear cutting and gas cutting can be applied to
COR-TEN in the same way as ordinary steel products. In
applying gas cutting to COR-TEN 570, the hardness
slightly increases near by cutting area. This level of
increase in hardness does not exert any appreciable
effect on the subsequent fabrication processes, but when
preheating and postheating are applied before and after
gas cutting, the subsequent cold working is favorably
attained.
■Spot Heating and Linear Heating for
Stress Relief
Stress relief of COR-TEN can be undertaken by means of
spot heating and linear heating. When COR-TEN is
heated to relieve stress in the same way as ordinary steel,
no deterioration in material quality occurs.
When the heating temperature is elevated beyond
800℃, due care should be taken because the material
strength and surface hardness increase while toughness
tends to decrease.
It is recommended that COR-TEN 570 be treated in
the same way as SM570.
Aside from COR-TEN 570, all grades of COR-TEN steel
can be hot-worked in the same way as ordinary carbon
steel. Because COR-TEN 570 is quenched and tempered,
it undergoes changes in material quality and suffers
drops in yield point and tensile strength when hot
working is applied at temperatures higher than the
tempering temperature. It is recommended that hot
working be conducted at temperatures of 600˚C or lower.
Absorbed energy
（J）
Brittle fracture ratio
（%）
Bond
●Preheating temperature : 50˚C
Base metal Interpass temperature : 100˚C
Weld metal ●Welding rod : CT-16 4.0φ
●Current : 180A
●Voltage : 24V
●Welding speed : 13cm/min
Absorbed energy
（J）
Brittle fracture ratio
（%）
■Manual weld joint (25mm)
■Cutting
Test temperature
（˚C）
Test temperature
（˚C）
New welding materials brand show in p30.
28
29
8
Joint Materials
Welding Materials
Bolt Joints
(1) Weather-resistant High-strength Bolts
The following welding materials for use with COR-TEN are prepared by Nippon Steel & Sumikin Welding Co., Ltd.
Welding Materials and Examples of Characteristic Properties
Designation
Welding
method
Tensile property
Brand name
Weldability is excellent in all positions. For the
welding of a thin plate less than 9mm.
NSSW CT-03Cr
NSSW CT-16Cr
NSSW SF-50W
FCAW
NSSW SM-50FW
COR-TEN 490
COR-TEN B
NSSW FGC-55 (P specifications) ※1
GMAW
NSSW YM-55W
SAW
SMAW
SAW
500
570
29
0
110
500
560
30
0
240
500
580
26
0
100
74
0.20～0.25 0.15～0.25 0.70～0.90
≦0.030
≦0.030
0.30～0.50 0.30～0.50 0.60～0.80 0.040～0.080
460
570
25
0
180
NWB110-MR 0.20～0.25 0.15～0.25 0.40～0.60
≦0.030
≦0.030
0.30～0.50 2.50～3.50
580
630
27
0
90
NSSW NF-810 × NSSW Y-CNCW
※2
For fillet and butt welding.
(vE0˚C : more than 27J)
480
600
23
0
47
NSSW NF-820 × NSSW Y-CNCW
※2
For fillet and butt welding.
(vE0˚C : more than 47J)
490
570
27
0
76
520
610
25
−18
180
630
685
22
−5
115
540
620
23
−5
70
540
640
26
−5
110
C
Si
Mn
P
S
For flat fillet and butt welding.
520
630
29
−5
88
NSSW NF-820 × NSSW Y-60W
For fillet welding.
540
640
25
−5
66
Notes: ※1 NSSW FGC-55 is P specifications (Paint). Other materials are W specifications.
※2 NSSW NF-810 is SAW flux for COR-TEN490B. NSSW NF-820 is SAW flux for COR-TEN490C.
● Regarding the welding materials for NAW-TEN series, refer to the catalog prepared exclusively for the series.
Cu
Ni
Al
Cr
─
─
Mo
B
─
0.0010～0.0030
0.15～0.25 0.0010～0.0025
■Mechanical Properties (Standard Values)
Bolts
Mechanical Properties of Test Pieces
Class by mechanical property
Mechanical Properties of Bolts
Yield strength Tensile strength Elongation Reduction of area
N/mm2
N/mm2
%
%
F10TW（S10TW）
900≦
F10TMR（S10TMR）
1000～1200
14≦
40≦
Note: The tension test is conducted using JIS Z2201 No. 4 test piece.
NSSW YF-15B × NSSW Y-60W
Class by mechanical property
Minimum tension load kN
Hardness
M16
M20
M22
M24
F10TW（S10TW）
157
F10TMR（S10TMR）
245
303
353 27～38HRC
Effective section of bolt（mm2） 157
245
303
353
─
Note: The figure in the table shows the minimum tension load that
can withstand up to the bolt fracture when the tension test is
conducted by inserting the wedge into the bearing surface of bolt
and on the condition of no breakage of bolt head.
Nuts
Class by mechanical
property
Hardness
Guaranteed load
F10W
F10MR
95HRB～35HRC
Same as minimum
tension load of bolt
Base metal
COR-TEN 490–CT-16
CT-16 is conventional welding material
Weld joint
(welding material) (Production discontinuation)
WEL-TEN 590–NSSW L-60
Corrosion loss (mm)
Manual welding test specimens were prepared for
COR-TEN 490 and WEL-TEN™ 590 in order to
compare the rates of corrosion between these two
specimens and base metal specimens (no joints)－
the results are shown in the figure on the right. The
test results show that the weld joints of both
COR-TEN 490 and WEL-TEN 590 have weather
resistance similar to the base metal.
（mass%）
0
120
■Exposure Test Results for Weld
Joints
Chemical composition
27
0
NSSW YM-60W
■Chemical Composition (Standard Values)
590
27
NSSW CT-60Cr
■Applicable sizes: M16～M24
510
600
Extra low hydrogen type electrode in all positions.
It assures excellent weldability, X-ray properties,
crack resistance and mechanical properties.
Diffusible hydrogen content is extremely low and
weld metal shows excellent crack resistance.
Weldability is excellent in all positions.
Diffusible hydrogen content is extremely low and
weld metal shows excellent crack resistance.
Weldability is excellent in horizontal fillet welding.
GMA welding wire for all positions to be used with
CO2 shield gas. Weldability is good in wide
current range.
F10TW and S10TW, and F10TMR and S10TMR are available as high-strength bolts for use with
weathering steel. It is recommended that F10TMR and S10TMR be used with the NAW-TEN series.
For more details, inquire at NIPPON STEEL & SUMIKIN Bolten Co., Ltd. (Phone: 81-6-6682-3261).
Material
NWB110
510
NSSW SM-60FW
GMAW
(J)
For flat fillet and butt welding.
FCAW
COR-TEN B-QT
Extra low hydrogen type electrode for welding of
medium and thick plates in all positions. Crack
resistance and mechanical properties are excellent.
Diffusible hydrogen content is extremely low and
weld metal shows excellent crack resistance.
Weldability is excellent in all positions.
Diffusible hydrogen content is extremely low and
weld metal shows excellent crack resistance.
Weldability is excellent in horizontal fillet welding.
GMA welding wire for all positions. Welding of
atmospheric corrosion resisting steel (P specifications)
for various structural works.
GMA welding wire for all positions to be used with
CO2 shield gas. Weldability is good in wide
current range.
vE
NSSW YF-15B × NSSW Y-CNCW
NSSW SF-60W
COR-TEN 570
Yield Tensile
Elongation Temperature
point strength
(Mpa) (Mpa)
(%)
(˚C)
Characteristics
SMAW
Impact property
Washers
Class by mechanical
Hardness
property
F35W
F35MR
35～45HRC
WEL-TEN™ is a registered trade name of Nippon Steel &
Sumitomo Metal Corporation.
Inquiry: Nippon Steel & Sumikin Welding Co., Ltd.
Shingu Bldg., 4-2 Toyo 2-chome, Koto-ku, Tokyo 135-0016 JAPAN
TEL.+81-3-6388-9000 FAX.+81-3-6388-9160
URL.http://www.welding.nssmc.com
30
Exposure year
31
8
MEMO
Bolt Joints
■Characteristic Performance Tests
Weather Resistance of High-strength Bolts
The exposure test results (1 year) for various kinds of high-strength bolts are shown in the figure below.
It is understood from the figure that these bolts demonstrate high characteristic performances.
Weather Resistance of Various High-strength Bolts (1st year)
Secular Changes
Industrial area
Industrial area
Coastal industrial area
(lapse of 1 year)
16
2
12
10
8
6
4
Carbon steel
（S40C）
12
2
2
Corrosion
rate
（gr/dm
腐食減量
gr/dm
腐食減量
（gr/dm
） ）
2
2
Corrosion
rate
（gr/dm
）
腐食減量
gr/dm
14
14
10
Ordinary steel
high-strength bolt
8
6
Weather-resistant
high-strength bolt
4
2
2
0
S40C
SAE1024B
SCM3
0.5　1　1.5　2　2.5　0.5
Exposure試験期間
period（年）
(year)
（試料は所定の強度レベルに熱処理
した
もの）
(Test piece: Heat-treated to
prescribed
strength level)
NWB110
Delayed Fracture Strength
High-humidity atmospheric delayed fracture tests and tightening exposure delayed fracture tests were conducted to
survey the delayed fracture strength.
High-humidity Atmospheric Delayed Fracture Tests
Tightening Exposure Delayed Fracture Tests
Main points in the test
Main points of the test
●Test method…Round bar notch tension test (stress concentration coefficient 4.5）
●Bolt size……………………………………………………M22×85
●Load stress…………………………………………………0.9N.T.S
●Tightening plate……………………………………………WT60R
●Atmosphere…Saturated vapor atmosphere(humidity:36～37˚C)
●Tightening outline…Nut rotation angle method（0.9N max.）; Plastic range tightening
●Exposure site……………………………………Minoshima Coast
Test results
Bolt
Weather-resistant
high-strength bolt
Ordinary steel
high-strength bolt
Fracture condition（as of December 31, 1992）
Delayed fracture time（hrs）
200
600
1000
1400
1264
1153
1800
1483
Bolt
Date to start exposure Number of test piece Fracture number
Weather-resistant high-strength bolt November 28, 1978
10
0
1396
1202
(2) High-strength Bolts for COR-TEN
The bolts and screws for use with COR-TEN are manufactured by Naigai Steel Industry Co., Ltd. (Phone: 81-6-6781-0031)
based on the order placed. The company will consult regarding bars and wire rods used as bolt materials.
32
33