Reaffirmed and updated as NACE SP0472-2020 . The change in nomenclature signifies the strengthening of the standard from a recommendation to a mandatory practice in many contractual agreements. Scope and Application of NACE SP0472
: While PWHT is a common method to reduce hardness and residual stress, SP0472 allows for other options like base material chemistry controls if PWHT is not feasible.
The standard specifically targets three integrated microstructural zones prone to high residual stress: the weld deposit, the heat-affected zone (HAZ), and the adjacent base metal. Mechanisms of Environmental Cracking Prevented nace rp0472 pdf new
for weld deposits to compensate for portable testing variations, which is more stringent than the 22 HRC limit often cited in upstream standards like MR0175. Heat-Affected Zone (HAZ)
(the merged organization of NACE International and SSPC) under Task Group 326. Key Technical Scope Reaffirmed and updated as NACE SP0472-2020
: Requires the HAZ of pressure boundary, internal attachment, and repair welds to comply with a maximum hardness of Postweld Heat Treatment (PWHT)
The "RP" in the original title stands for "Recommended Practice." In 2010, NACE International (now part of AMPP) made a global change, redesignating all "Recommended Practices" as "Standard Practices" to better reflect their industry consensus and authority. Thus, the "new" designation became , though professionals still commonly refer to it by its original "RP0472" name during searches or in conversation. Key Technical Scope : Requires the HAZ of
To successfully comply with the active version of the document, fabrication shops must enforce rigorous metallurgical boundaries during the development of their Welding Procedure Specifications (WPS):
: Users are cautioned that thermal cutting processes also produce a HAZ that may require the removal of approximately 3mm of material to eliminate high-hardness zones. Historical Context
The standard dictates specific locations for hardness tests on cross-sections of the weld, including base metal, HAZ, and weld metal.