PWHT OF 304H
PWHT OF 304H
(OP)
Our customer is stipulating that PWHT is required for some 3/4" thick 304H plate on which we will be applying hardfacing. ( St. 6) They don't provide a PWHT temperature or hold time and I'm wondering if anyone has experience with PWHT on an application like this?





RE: PWHT OF 304H
PWHT is not required. However, preheat will be required for the Stellite 6 to avoid cracks. We have applied Stellite 6 to other substrate materials, and I needed to preheat up to 600 deg F to prevent cracks after welding in the HF, there was never a need to PWHT.
RE: PWHT OF 304H
Thanks for the reply. My experience is similar. When overlaying with Stellite 6 we normally preheat to 500 F minimum and maintain that minimum temp throughout welding, then wrap and slow cool. For Stellite 1 we use 1000 F. In this case, our customer specifies that PWHT be performed prior to grinding the overlay. We're going to have a vendor put the parts on a reciprocating grinder and grind them smooth. I'm assuming our customer is looking for a thermal stabilization prior to the grinding, but, in my limited experience with thermal stabilization treatments it seems to me they're more like a ritual than a science, and I'm not sure what, if any, heat treatment will accomplish a stabilization.
RE: PWHT OF 304H
S.
http://www.corrosionist.com
RE: PWHT OF 304H
http://www.hghouston.com/ss_heat.html