SAFEGUARD YOUR DESIGN...
AND YOUR REPUTATION
I S Y O U R P R O J E C T AT R I S K ? S A F E G U A R D Y O U R S E L F,
YOUR CLIENT AND THE PUBLIC.
Today, due to market conditions
and exchange rates, there is an
increased chance you or your steel
fabricator could be offered
imported Steel Hollow Sections
produced to standards other than
Australian Standard AS 1163 that
could put your business at risk.
Frequently these products are designed
for applications such as fluid conveyance
and other general non-structural
repetition type applications, but never
intended for use in structural applications
within the Australian construction
industry or for other engineered
structures designed to AS 4100.
There is a risk that steel products not
complying with AS 1163 can be offered
or may be incorrectly substituted without
fully realising the serious implications
involved when the product is to be used
for an engineered structure or building.
Substitution with tubular products not
complying with AS 1163 or AS 4100
rules can and has occurred, with
costly consequences.
The Risks?
IN DESIGN
Structures may be overloaded
•
onesteel market mills - editorial
Published design capacity tables and
software databases used by Australian
engineers to design to AS 4100 are
calculated on the basis of using
AS 1163 compliant material.
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•
The AS 4100 capacity reduction factors
have been determined for product
complying with the AS 1163 mass
tolerance. Whereby the mass tolerance
of a length of hollow section shall not
be less than 0.96 times the specified
nominal mass to produce a more
consistent product with the wall thickness closer to the nominal.
•
A number of imported tubular
specifications such as BS 1387 (CHS)
and ASTM A500 (SHS/RHS), do not
match the dimensional and mass
tolerances of AS 1163, and it is
possible for them to be only 90% of
their specified nominal mass.
•
BS 1387 and ASTM A500 product
should not be designed to AS 4100
design rules, unless derived design
capacities are reduced to account for
their greater variation in mass.
Stuctures may not comply with
statutory requirements
•
AS 1163 is widely referenced in
other building codes and Australian
Standards such as Australian Standard
AS 1554: Part 1, Welding of steel
structures.
Load capacity of structures may
have to be reduced
•
All Structural Steel Hollow Sections
made to standards other than AS 1163,
and unidentified Steel Hollow Sections,
must be tested and certified in
accordance with AS 1391: Methods for
tensile testing of metals. Otherwise
non-conforming specifications must be
downgraded to a design yield strength
of only 170MPa.
Structures may be susceptible
to brittle behaviour
•
Many overseas standards including
BS 1387 and ASTM A500 do not have
a requirement for “notch toughness”.
Sections produced by OneSteel Market
Mills comply with the LO requirements
of AS 1163, LO grades are impact
tested to ensure the section is suitable
for use in cold storage applications,
and applications subjected to
impact loading.
“Grade 350”
does not mean
it necessarily
complies with
AS 1163.
Hence for the designer, the use of
Structural Hollow Sections not complying
with AS 1163 can result in a significant
amount of extra work to ensure the design
is fit for purpose.
Overseas standards are designed to
comply with the design codes of the
country of origin. Their use in Australia
requires careful consideration as to
whether they may compromise
your design.
processes (ingot cast steel) used in some
South East Asia and Eastern European
developing economies, that can produce
steel that is inherently higher in
impurities (non-metallic inclusions) and
have higher silicon residuals and poor
steel cleanliness.
IN FABRICATION
The photograph right, highlights a
problem brought to our attention that was
experienced with a recent project. This
sample of imported galvanized pipe
(CHS) was improperly substituted for
AS 1163 specified product.
Chemical composition of steel can
be just as important in fabrication as
the mechanical properties that are used
in design.
Some characteristics the sample
exhibited were:
Imported pipe (CHS)
Silicon killed steel
Splitting
Note: OneSteel Tubeline® CHS (and
Tubeline® & DuraGal® RHS/SHS) products
are manufactured from continually cast,
fine-grained steels. The superior cleanliness
and chemical composition of these steels
means they do not contain the harmful
inclusions that led to the type of failures
seen above, and the very low residual of
silicon avoids the difficulties with
galvanizing either during manufacture
or after fabrication.
The sample of imported CHS split on
manipulation. Laboratory testing revealed
the cause was a lack of ductility due to
a combination of grain size and poor
steel cleanliness.
Zinc flaking off
Silicon killed steels can cause problems
as the silicon increases the reactivity of
the steel in the molten zinc bath that can
result in excessively thick and brittle
galvanized coatings. The result can be
added difficulty in processing these
steels during galvanizing, or in the case
here, the thick zinc layer can flake off
during manipulation. The example
here is of course extreme, but problems
with galvanizing silicon killed steels have
been documented by galvanizing
associations worldwide.
Minimize the Risk!
Because plans, specifications and bills
of materials can often pass through
several hands, abbreviations such as
“C350” or “grade 350” can appear on
order documents which may lead to
misinterpretation in the supply chain.
It is important to fully describe the
product as conforming to AS 1163
Grades C250LO, C350LO and C450LO
Some of the problems can be traced to
the older steel making manufacturing
(if it has been designed using such)
on all related documents, to safeguard
the project against substitution with
non-conforming products.
Ensure the fabricator understands the
need to order tubular structural steel
complying with AS 1163, or if you are
directly involved with the steel supplier
make sure you are ordering tubular
hollow sections that comply with
AS 1163.
Australian Standards AS 4100 and
AS 1163 were developed to safeguard
the Australian construction industry.
This imported,
non-conforming
galvanized CHS ended
up in a structural
application for bolted
bracing members.
Failure (splitting)
occurred during
manipulation.
Replacement with
galvanized material
complying with
AS 1163 performed
successfully – as
expected.
AS 1163 – it’s your
safeguard, why take
the risk with
anything else.
Summary: Comparison of AS 1163 with two commonly imported specifications
Property
ASTM A500
(CHS)
BS 1387
(CHS)2
Grade A
AS 1163
(CHS)
ASTM A500
(SHS,RHS)
AS 1163
(CHS, SHS,RHS)
C250L0
Grade B
Grade C
C350L0
Yield Strength (min) MPa
228
195
250
317
345
350
Tensile Strength
(min) MPa
310
320
350
400
427
430
Mass Tolerance
96% of specified
✘
✘
✔
✘
✘
✔
Impact Tested
✘
✘
✔
✘
✘
✔
Low Temperature Service
✘
✘
-20º C t ≤ 6.0mm
-30º C t > 6.0mm ≤ 12mm
1
-20º C t ≤ 6.0mm
-30º C t > 6.0mm ≤ 12mm
1. All Structural Steel Hollow Sections made to standards other than AS 1163, and unidentified steel hollow sections, must be tested and certified in accordance with
AS 1391:Methods for tensile testing of metals. Otherwise non-conforming specifications must be downgraded to a design yield strength of only 170MPa.
2. BS 1387 more closely resembles AS 1074: Steel tubes and tubulars for ordinary service.
✘ Features not tested or specified within Standard.
This publication has been prepared by OneSteel Market Mills, an operating business group of OneSteel Trading Pty Limited ABN 50 007 519 646. Please note that any specifications or technical data referred to in this publication are
subject to change and/or variation or improvement without notice and no warranty as to their suitability for any use is made. Users of this publication - to ensure accuracy and adequacy for their purposes - are requested to check the
information provided in this publication to satisfy themselves as to its appropriateness and not to rely on the information without first doing so. Unless required by law, the company cannot accept any responsibility for any loss, damage or consequence resulting from the use of this publication. Photographs shown are representative only of typical applications, current at April 2004. This publication is not an offer to trade and shall not form any part of the trading
terms in any transaction. ©Copyright 2004. OneSteel Market Mills. Registered Trademark of OneSteel Market Mills, DuraGal®, TUBELINE®.
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