Revisions Reflect Industry Concerns
(Originally Published 24 October 2016)
Earlier this year revisions to Australian Standards and Technical Specifications covering structural steels were released by Standards Australia.
The revisions were a result of increasing concerns in the construction industry about non-compliant building materials and the risk they pose to the industry and community generally.
Three key areas of weldability, certification and product conformity were addressed in the revisions. Additional changes were also made in an effort to harmonise the four Standards with each other and their international equivalents.
To ensure steel supplies remain prequalified for welding, technical specification TS 102-2016 was released, which outlines limits on elements added to steel. This technical specification seeks to mitigate the risk of supplying steel that is not prequalified for welding.
Recent reports suggest some imported steels have measured levels of boron in excess of residual quantities. This is an indication boron may have been intentionally added. The addition of boron is known to have a negative impact on the weldability of steel. If steel is welded with boron present in excess of 0.0008 per cent there is an increased risk of weld failure.
The new technical specification supplements the four structural steel Standards and now requires limits on alloying elements to be listed in the test certificates in accordance with the Steel Products Standards.
The Australian Steel Institute, the Welding Institute of Australia and the Heavy Engineering Research Association New Zealand all recommend that SA TS 102 – Structural steel: Limits on elements added be referenced in specifications whenever any of the four structural steel Standards are referenced. They also recommend SA TS 103-2016 – Welding to AS/NZS 1554 Parts 1, 5 and 7 – Limits on boron in parent materials is referenced whenever AS/NZS 1554 parts 1, 5 or 7 are referenced. This ensures the products supplied are prequalified for welding to the Standard.
Liberty OneSteel’s hot rolled structural products and cold-formed hollow sections have no added boron and are prequalified for welding to Australian Standard AS/NZS 1554 parts 1, 5 and 7.
In the latest revisions of all four Standards, a new mandatory requirement is for test certificates to be made available for a purchaser of products. Mandatory minimum requirements to be reported on the test certificates have been modified slightly, including the requirement to report the amount of boron in the chemical composition and any other element intentionally added.
Australian Standard AS 4100 – Steel Structures recognises that test certificates from a steel mill are sufficient evidence of the steel’s compliance with the four Structural Steel Standards.
The new product conformity requirements in combination with the test certificates are designed to prevent the re-grading of product from a lower to a higher grade based on the test reports on a test certificate or conducted by a testing laboratory.
A test certificate for a product is required to nominate the grade to which the product is manufactured. This is the grade to which the product shall be designed, specified and procured. While the certificate will have test results reported, these values are not those that are to be used in design or (re)grading of the product.
The Steel Products Standards now require type testing to produce a minimum of 30 consistent and satisfactory test results on product manufactured in a facility with demonstrated factory production control in order to grade or re-grade a product.
To guard against non-prequalified steel products, engineers should ensure TS 102-2016 – Structural Steel – limits on elements added, is included in their documentation when the following Australian Standards are specified:
- AS/NZS 1163-2016 Cold-formed structural steel hollow sections
- AS/NZS 3678-2016 Structural steel – Hot rolled plates, floorplates and slabs
- AS/NZS 3679.1-2016 Structural steel – Part 1: Hot rolled bars and sections
- AS/NZS 3679.2-2016 Structural steel – Part 2: Welded I sections
Procurers and fabricators of steel product compliant to the Standards listed above can manage their risks of using non-prequalified product by insisting product meets the requirements of SA TS 102-2016 and SA TS 103-2016 Welding to AS/NZS 1554 Parts 1, 5 and 7– Limits on boron in parent materials.
Projects that specify these newly released Standards and Technical Specifications will be in a better position to avoid the risks that might otherwise exist.