Volume 23 Counterfeit Squirter DTI Washers

HOBSON
THE
Volume 23
WARNING: Counterfeit Squirter Washers
Fasteners make up as little as
2% of the total cost of a structual steel project. However, bolts
hold the entire project together!
For the sake of a few dollars, is it
really worth using an inferior product
for such an integral part of any structure?
The DTIs® (Direct Tensioning
Indicators) shown, were used
in the Australian market, and clearly
illustrate the risk of using cheaper alternatives. The Australian structural
market has seen the replacement of
recognised brand AS1252 products,
with cheaper products, of significantly lower quality.
Despite the slow market conditions.
Hobson do not sacrifice quality for
price. Hobson Squirter DTIs® are
manufactured to ASTM F959M, and
are the eastiest and most efficient way
to ensure correct tensioning on AS1252
structual assemblies.
The use of the Squirter DTIs® is covered under AS4100 Steel Structures
(15.2.5.3).
All Hobson Squirter DTIs® are heat
treated, and produce an orange
‘squirt’ to indicate when the assemblies are sufficiently tensioned. This
added benefit makes it virtually impossible to over-tension. This also reduces the impact of the factors influencing the torque calculation process,
such as weathering, poor lubrication
and damaged threads. The DTIs® are
a mechanical load cell in their own
right, which makes them the most accurate way of measuring tension.
In This Issue:
Counterfeit DTI’s found in
the Australian market.
Counterfeit Squirter Washers
1
Anchor Design & Installation
3
Blue Coated AS1252 Nuts
4
Magnetic Permeability of
Stainless Steel
5
Mechanical Properties of Stainless Fasteners at Elevated Temperatures
6
Hobson Newsfeed
6
Cryptic Quiz
7
www.hobson.com.au
TDX™
XBolt™
Drillx™
ClawBolt™
Hobson Squirter DTI® Washer
The Best Way to Bolt!
Hobson Engineering has been exclusively distributing the Applied
Bolting Squirter DTIs® since 2006.
Applied Bolting Technology is an
American company which holds
patents for Squirter DTI® washers
and other load-indicating washer
devices. All of their products are
manufactured in the USA from
locally produced steel.
All Squirter DTIs® supplied by
Hobson are stamped with an
individual lot number. Through
the lot number, all DTIs® are
traceable to date of manufacture
and compression load properties.
Test certificates are available to
download free of charge from our
website.
www.hobson.com.au
Squirter DTIs® are DTIs with
flexible silicone embedded in the
impressions under the bumps with
a channel leading to the outer
diameter. They form part of a compressible washer fastening system
which indicates proper bolt tension,
independent of torque. When the
bumps are compressed, the bright
orange silicone squirts out through
the channels.
Squirter DTIs® are very well known
and held in high regard in the
industry. The Bechtel Group specifies the use of Squirter DTIs® on
all fully tensioned friction and load
bearing bolted assemblies.
T
’
N
O
D
Don’t use counterfeit products
to save a few dollars...
FA K E IT
Always use a high quality Hobson
Squirter DTIs® with a high quality
Hobson structural assembly to ensure
you get the job done right the first
time, every time!
www.hobson.com.au
SampsonRod™ TygaBolt™
Conxtruct™
HOBSON
THE
Anchors:
… How should anchors be qualified?
Nowadays, connecting structural steel components
to concrete is made possible using concrete anchors.
There are two types of anchors widely used for this
purpose – Cast-In-Place (CIP) Anchors and PostInstalled (PI) Anchors. CIP anchors come in different
forms and sizes. Commonly used types are shown in
Figure 1.
Fig. 1 Headed Bolt, L- Bolt, J-Bolt, Stud welded Plate
As the term implies, they are positioned into place before the concrete is poured, thus demanding a higher
degree of accuracy in laying out the anchor locations.
On the other hand, PI Anchors are installed after the
poured concrete has come to an acceptable level of
curing. Installation is done by drilling the anchor hole,
using either a diamond coring machine or a hammer
drill. PI Anchors can be mechanical or chemical as
illustrated in Figure 2.
Given that structural anchors are used for structural
applications, load bearing performance is
an integral part of the connection design qualification
process. The design, construction and management of
concrete structures are well covered in AS3600. Similarly, AS4100 offers the same level of detail for steel
structures.
- Ramil Crisolo (Hobson’s resident Anchor Guru)
Currently, there is no Australian Standard that
offer the same level of qualification process for
the anchor - the component that connects the
structural steel element to concrete.
CIP anchor connection designs are left to the
resourcefulness of the individual design engineer. The commonly used standard for CIP
anchor design is ACI 318 (Appendix D), while for
PI anchors, design model references are mostly
manufacturer recommended. Usually, PI manufacturer recommendations are based on either
in-house proven design models or standards like
ETAG. These situations lead to a huge difference
on how anchor connections are qualified and
have largely lead to the establishment of AEFAC
(Australian Engineered Fasteners and Anchors
Council).
AEFAC is an industry initiative seeking to enhance the specification, selection, design and
installation of structural anchors and fasteners
in the Australian construction industry. AEFAC
is a consortium made of Swinburne University
of Technology and a number of leading fastening companies in Australia. Hobson Engineering
is one of the founding members who stepped
forward and committed to take part in AEFAC’s
cause, which is to have Australian standards that
unify the selection, specification and application of anchors and fasteners in the construction
industry.
More information about AEFAC can be found at www.aefac.org.au
“None of us is as smart as all of us” - Eric Schmidt
TDX™
XBolt™
Drillx™
ClawBolt™
Fig. 2 - Chemical Anchors & Mechanical Anchors
orange is good
...and so is Blue!
Hobson are introducing -
Blue coated AS1252 Structual Nuts
→ “All hot-dip galvanised (HDG) nuts shall be provided with an
additional lubricant coating to prevent seizure on assembly. The
coating shall be clean and dry to the touch.”
→ To ensure that this coating has been applied, Hobson have
specified a visual indication so the installer can be assured that
the nut is correctly galvanised and lubricated.
→ Blue also indicates that the nut has been tapped once after heat
treatment and galvanising.
→ Assembly testing in Australia has clearly indicated that structual
nuts must be:
→ Free from galvanising within the threads.
→ Lubricated correctly. If not, they may seize on the thread of
the bolt and fail to achieve
minimum proof load, as
specified in AS4100.
...bolting made safe,
easy and accurate.
“I love deadlines. I love the whooshing noise they make as they go by” - Douglas Adams
SampsonRod™ TygaBolt™
Conxtruct™
HOBSON
THE
The secret law of Attraction
...in magnetic permeability of Stainless Steel.
Magnetic permeability is the property used to
measure the degree to which a material is
attracted to a magnetic field. It is a relative
measure that is compared to a datum for air or a
vacuum having a reading of 1.
There are a number of factors that affect the
magnetic permeability of stainless steels. The
rule of thumb that is used to determine if a metal
is stainless steel of “if a magnets sticks, its not
stainless” is far too simple and incorrect.
Both 304 and 316 grades of stainless steel are
regarded as being non magnetic in their annealed conditions. However after cold working
they become attracted to a magnetic field. The
cold working process can take many forms,
pertinent to fasteners are, drawing (reduction of
area), thread rolling, forming and forging. The
transformation occurs when the microstructure
of the stainless steel changes from austenite to
martensite. The amount of transformation, and
hence degree of resulting magnetic response, is
determined by both the amount of cold work and
the Nickel:Chromium ratio. Hence the low Nickel
grades 302,303 and 304 can be strongly responsive. Higher Nickel grades such as 316 only ever
show slight response, while very high Nickel
grades such as 310 never show any response.
The effect is also variable within the composition
specification limits of a particular grade, so two
heat lots of type 304 with slightly different Chromium and Nickel contents could vary markedly
in their response to an identical amount of cold
working. If it is important for a particular end use
that a product must have a very low magnetic
permeability, it is suggested that either the steel
be annealed as a final operation (often not practical and also reduces the tensile strength), or a
higher grade be used such as 316.
ASSDA technical buttetin, Atlas Steels technical data book, University of
California paper, “Magnetic Permeability of stainless steel for use in accelerator bean transport systems”.
In contrast to the austenitic alloys, ferritic
stainless steels such as 420, duplex and superduplex are strongly attracted to a magnetic field
because they contain a ferrite microstructure.
Even annealing will not substantially reduce the
magnetic permeability.
Electrical demagnetising treatments on stainless steels are largely ineffective.
Alloy
304
316
Cold
Relative
Reduction % Permeability
0
13.8
32.0
65.0
84.5
0
13.8
32.0
65.0
84.5
1.0037
1.0048
1.0371
1.5400
2.2000
1.0030
1.0030
1.0040
1.0065
1.0070
Tensile
Strenght
MPa
558
697
1006
1243
1398
576
812
1102
1227
1338
- Measurements in oersteds
- Data presented to illustrate effects of cold working and
should not be interpreted as actual values for grades. Magnetic Permeability is dependent on Ni/Cr ratio.
- The magnetic permeability values may be compared to a
mild or carbon steel of at least 200.
www.hobson.com.au
TDX™
XBolt™
Drillx™
ClawBolt™
MECHANICAL PROPERTIES OF STAINLESS
FASTENERS AT ELEVATED TEMPERATURES
Assuming the correct matching class of nuts are used they will automatically meet the requirements,
and hence it is suffucient to consider the mechanical properties of only the bolts, screws or studs.
The following data is for guidence only and is taken from ISO3506
and Bumax technical publications. Users should understand that the
actually chemistry, the loading of the fastener and the enviornment
can cause significant variations.
When the operational temperature rises, strength is reduced.
Influence of Temperature on lower yield stress ReL and stress at 0.2% Rp0.2
Grade
+100oC
+200oC
+300oC
+400oC
+400oC
70
80
Bumax 88
Bumax 109
85%
85%
90%
95%
80%
80%
90%
95%
75%
75%
85%
90%
70%
70%
80%
90%
No Data
No Data
75%
80%
The FIRST person to correctly
complete the crossword on the
following page will win a $200
Coles Gift Card !!!
Hobson Newsfeed :
HOBSON
HEROS
NS2 “Tough Mudder” Players - Mickaela, Deion, Emma & Alan.
“Will you succeed? Yes, you will indeed! (98 and 3/4 percent guaranteed)” - Dr. Seuss
SampsonRod™ TygaBolt™
Conxtruct™
THE HOBSON
The across clues in this crossword are all words
found in the Hobson catalogues (except for 16 &
24). The across clues have no ‘straight’ clues, only
a cryptic clue. The down clues (and across 16 &
24), have both a ‘straight’ and a cryptic component.
Q
U
I
Z
Across:
1. Eat fortified wine. (7)
5. What Paul Keating was accused of
during the Queen’s visit. (6)
11. Confused ironic degradations. (5)
12. Everyone suffers a mixed-up lack.(9)
13. Backward gobblinf man. (3)
14. Selkcub. (11)
16. Coin of the Nord-Lock products. (6)
18. ‘E’ is one.... (3)
19. Cable of high act. (4)
22. I go through mountain pass. (4)
23. Backward American lass. (3)
24. Regarding tailess Indian loincloth is
alarmingly warm. (6)
26. Bottomless round thing we object
swaps. (11)
28. Forward American lass. (3)
30. Join up either at the end... (9)
32.. ...or twist the lower colon. (5)
33. Confused better halves before lesser
beginning. (6)
34. ‘E’ is one of these, too. (7)
Down:
2. Chase after mixed-up and without
its tail to overthrow. (5)
3. Statement that assumes the fact that Peter Hobson’s father made an antimatter particle. (8)
4. Fixes minus its prime initial opens and closes the window in a room repeatedly. (6)
6. Moral code to reorganise quote containing heroin. (5)
7. Backward fish not on the windward side. (3)
8. To cut up for a second time an inebriated ‘Cider Tess’. (9)
9. No tickets contain elements of the ear. (4)
10. Cry over the whale meat. (7)
15. She got stabbed in the shower at Tara. (5)
16. Commissions to players who put the boot to the faster members of the football team. (9)
17. Bay window, that is, between right and left after nothing. (5)
20. Tell a story that addles a terran. (7)
21. Clothing for blokes that gives me a confused answer. (8)
25. The first woman to swim the English Channel reeled with excitement. (6)
27. A vegetable to enjoy spending 16-across. (5)
28. Keel talking in central west African country. (5)
29. Grass starting long-awaited woollen nighties. (4)
31. Dat town in Vietnam. (3)
You can thank Jim Butler for this one!!
Save 25% on your bolting installation cost.
Ask us how.
AS1252
Structural Assembly
Squirter® DTI Washer
Bolting made Safe,
Easy and Accurate
Hobson Structural Assembly.
Squirter® Direct Tension Indicator Washer.
TONE® Electric Torque Control Wrench.
Featuring:

2 x Safety Reaction Arms

L-Shape Arm + Long Bar Arm 230mm

Light Weight

Non Impacting

Low Noise

Automatic Shut-off at Preset Torque
TONE® Electric Torque
Control Wrench
Since 1935
....because quality matters
www.hobson.com.au