Materials, documentation and traceability under AS/NZS 5131

Why materials control matters to an assessor

A fabricated member is only as reliable as the steel, consumables and fasteners it is made from. Section 5 of AS/NZS 5131 requires that the properties of supplied materials are documented so they can be compared with the construction specification and the referenced product Standards (Clause 5.1.1), and that these operations run under a suitable quality management system (Clause 5.1.2 – see quality management). For an offshore fabricator, the paperwork trail from mill to piece mark is often the first thing an Australian certifier samples – before looking at a single weld.

Designation and inspection documents

Clause 5.2.1 requires the construction specification to designate every material in the terms of its product Standard (for example a grade and quality to AS/NZS 3678 or AS/NZS 3679.1, or a coating class to AS 1397). For CC2, CC3 and CC4, where different grades are in circulation together, each item must carry a mark identifying its grade. If marking is required and an item is unmarked, it is treated as nonconforming product.

Clause 5.2.2 then defers to the product Standard for inspection documentation. In practice, Australian structural steel Standards require a manufacturer's test certificate stating heat number, chemical analysis and mechanical test results for the material supplied. Engineers familiar with European practice will recognise this as broadly equivalent to an EN 10204 type 3.1 inspection certificate – specific test results, issued by the producer's authorised inspection representative independent of production. A type 2.2 "typical values" document is generally not sufficient where specific results are needed.

ACRS context: AS/NZS 5131 itself does not name a certification scheme, but many Australian specifications require steel from mills holding ACRS (Australasian Certification Authority for Reinforcing and Structural Steels) third-party product certification. Where specified, the mill certificate should be checked against the mill's current ACRS scope for the product, Standard and grade supplied.

Lot, piece-mark and piece traceability

Clause 4.7 defines three levels, each a step up in rigour:

• Lot traceability (4.7.2) – a batch of identically fabricated components can be traced back to a set of parent test certificates, but no single certificate is tied to an individual piece.
• Piece-mark traceability (4.7.3) – every piece mark (which may cover many identical pieces) is traceable to its parent certificates through fabrication and into the works, with all plate and section correlated to certificates and receiving inspection records.
• Piece traceability (4.7.4) – the same, but for each individual piece of steel.

In all three, identification must be transferred to offcuts returned to stock before they are allocated to another job – a common audit finding. Clause 5.2.3 links these levels to the construction category, with different rules for Australia and New Zealand. Our summary (refer to the current edition of AS/NZS 5131 for the full requirements):

Identification during fabrication (Clause 6.2)

Clause 6.2 turns those levels into a working system. The fabricator must keep a record of the mill test reports and certificates for every item of steel received, and establish a tracking system that supports Clause 5.2.3. For New Zealand CC3 and CC4 work the tracking system must also link welders (by weld plan or ID stamp for primary connection welds) and welding procedures to individual welds – which aligns with the welder and WPS traceability listed for CC3 in Table 7.4 of the welding chapter.

Marking must not damage the steel. Unless the specification says otherwise, hard-stamped, punched or drilled marks are limited to grades up to Grade 350, must not be used on coated cold-formed components, and only belong in areas where fatigue life is unaffected. Where hard stamps are prohibited (for example near plastic hinge zones or fatigue-sensitive details), the specification should state whether low-stress stamps are acceptable. Any member that cannot be clearly identified is classed as unidentified steel and dealt with under Clause 13.3.7.

Structural steel, consumables, studs and grout

• Structural steels (5.3) – grades, qualities, coatings and options are set by the specification; in Australia products must meet the Standards called up by AS 4100 or AS 5100.6, in New Zealand those of NZS 3404. Seismic, fracture-critical and through-thickness (Z-quality) requirements to AS/NZS 3678 must be stated where needed (5.3.4, 5.3.5).
• Welding consumables (5.4) – must comply with the Standards listed in the relevant part of AS/NZS 1554; batch certificates belong in the material records.
• Studs and shear connectors (5.6) – arc-welded studs comply with AS/NZS 1554.2, each supplied with a suitable ferrule; grade, type and length come from the specification.
• Explosive fasteners (5.7) – comply with and are installed to AS/NZS 1873.
• Grout (5.8) – cement grout, special grout or small-aggregate concrete, with mix richness tied to the bedding thickness; special grouts follow the manufacturer's instructions.

Mechanical fasteners and their traceability

Clause 5.5 calls for fastener coatings that are compatible within the assembly and comparable in corrosion resistance to the connected steel, with hot-dip galvanized fasteners to AS/NZS 1214. Snug-tight (/S) bolts, nuts and screws follow the AS 1110/1111/1112 series with properties to AS 4291; tensioned (/T) assemblies must comply with AS/NZS 1252.1. Direct tension indicators follow ASTM F959 and are not used with weathering steel. Footing bolts have their own rules – notably, welding of property class 8.8 and above is not permitted (5.5.7).

Clause 5.5.12 requires fasteners to be delivered and identified as their product Standard demands. For high-strength assemblies that means keeping bolts, nuts and washers as matched, labelled lots with the manufacturer's test documentation, and not mixing lots or coatings. See AS/NZS 1252 structural bolts and the mechanical fastening chapter.

Storage and export considerations

Clause 5.9 expects all materials, including client-supplied items, to be stored so they are not harmed, and identification must be maintained during storage. Appendix D reinforces this at CC2 and above with protection from the environment. For a fabricator in a tropical climate this means covered, raised storage for plate and sections, dry storage and conditioning for low-hydrogen consumables, and sealed, labelled containers for fasteners. For export, certificates should be in English and cross-referenced to heat numbers, piece marks and packing lists so the site team and certifier can trace any item on arrival.