AS/NZS 1554.1:2011 - Implications for Existing Welding Procedures
As mentioned in last month's HERA News, the 2011 version of our most widely used welding standard AS/ZNS 1554.1 has now been published; superseding the 2004 edition. While this latest version maintains the established principles of earlier editions, there are detail changes that now need to be considered by fabricators and inspectors.
A significant change is that the new edition is now up-to-date with the current AS/NZS welding consumable standards. Over the last few years, Australia and New Zealand have adopted the harmonized ISO welding consumable classification system for the manual metal arc welding (MMAW) and flux-cored arc welding (FCAW) processes. This means that fabricators will need to revisit their welding procedure specifications (WPSs) and update them as required in respect to MMAW and FCAW consumable specifications where this has not already been done.
This is particularly important where welding consumables are treated as "prequalified" as mistakes here can lead to welds that will not provide the mechanical properties the designer of a structure intended. A fundamental principle of the AS/NZS 1554 series of standards is that welding is carried out in accordance with a qualified WPS. There are various ways of qualifying a WPS, the most common being the "prequalified" option. A procedure can be deemed prequalified when various conditions are met including the use of "prequalified" consumables.
To be considered prequalified a
consumable must meet these criteria:
• compliance with the appropriate AS, AS/NZS, or ISO standard, or have a ship's classification society approval grading,
• be matched with the steel type (this may in turn have impact test and heat input requirements),
• be used within the welding parameter ranges specified by the manufacturer.
A consumable may also be considered prequalified when specified in a WPS suitably qualified to another standard. Where consumables do not meet these requirements qualification by testing is mandatory. The requirements of AS/NZS 1554.1 are not met when a WPS only records a trade name or an AWS classification.
While the use of prequalified consumables simplifies the establishment of a WPS it will not necessarily guarantee sound welds. Adequate fabrication ability is always required together with effective and knowledgeable welding supervision. The choice of consumable is ultimately the responsibility of the fabricator and they need to be conversant with the standard's requirements and not rely solely on third parties for consumable selection.
While aspects of qualification such as establishing draft procedures and the preparation and assessment of test pieces may be sub-contracted, the fabricator remains responsible for the use of welding procedures. The changes to the welding consumable classifications systems used in Australia and New Zealand now mean fabricators (and inspectors) will need to check and revise WPSs as necessary to ensure they are valid.
Appendix F in the 2011 edition of AS/NZS 1554.1 offers guidance on the extension of existing weld procedure qualification. Weld procedures qualified using consumables classified under the former systems remain valid and may continue to be used without further qualification provided consumable equivalence can be established.