DNV DNVGL-RP-B204 [ Revised ]

This recommended practice (RP) provides the technical requirements for welding of subsea equipment. This includes requirements for quality assurance, welding procedure qualification, non-destructive testing and inspection, and welding and inspection personnel. The scope covers welding of the following pressure retaining equipment:

— subsea wellhead and tree equipment as per ISO 13628-4 or API Spec 17D

— manifolds as per ISO 13628-15 or API RP 17P

— flowline connectors and jumpers as per API RP 17R

— workover riser systems as per ISO 13628-7 or API Std 17G

— control systems consisting of small-bore tubing and piping as per ISO 13628-6 or API Std 17F.

The following types of welds between forged or hot isostatic pressing (HIP) materials and pipe materials are included:

— girth welds in carbon steels (CS) and low alloy steels (LAS) with and without internal cladding

— corrosion-resistant overlay welding with corrosion-resistant alloys (CRA), i.e. cladding, load bearing and non-load bearing

— girth welds of dissimilar materials, including LAS and Ni-based buttering

— girth welds in 22Cr and 25Cr duplex stainless steels

— single sided girth welds in small-bore tubing and piping in selected CRA materials, i.e. duplex and austenitic stainless steels and nickel alloys, typically 22Cr and 25Cr duplex, AISI 316L, XM-19, 6Mo, alloy 625.