We need to weld an austenitic stainless steel , set-on, nozzle (316L) to a carbon steel barrel of a compressor. This will be done using austenitic stainless steel filler material, SMAW. A 309/ 316 buttering layer will be deposited onto the carbon steel, where the nozzle is to be located, followed by PWHT, and the final weld completed using 316L; this will be done in accordance with QW 283, ASME IX.
The carbon steel barrel is about 150mm thick and the nozzle approximately 90mm, the buttering layer will be 5mm thick. The nozzle will be set on.
How long does the holding period for the PWHT of the buttering layer need to be? There are no through thickness welds in the barrel.