S41008 (410s) P7 PWHT Conditions?
S41008 (410s) P7 PWHT Conditions?
(OP)
I have a project currently underway which involves .500" SA-240 Type 410s (P7 Gr. 1) and the client is imposing a MDMT/CET of -20°F. We have completed the production impact plates as required by ASME VIII-1 (UHA-51(h)) and according to UHA-32 the PWHT of this material is required to be performed at 1400°F minimum. The WPS used utilized E410 filler metal. My question is that the PWHT is required be performed at 1400°F with a specified cooling rate from soak to 1200°F at 100°F/hour maximum then below 1200°F, "after which the cooling rate shall be sufficiently rapid to prevent embrittlement". With this being said, I performed the PWHT as follows: From 600°F to 1400°F maximum heating rate of 400°F/ hour, held at 1400°F for 1.0 hour, from 1400°F to 1200°F maximum cooling rate was 100°F/ hour, then pulled the coupon from the oven and allowed to cool in still air. When I sampled the impact tests for the Weld & HAZ as required, my results were VERY low....lateral expansion < .003". My question is has anyone experienced this, if so, what was the process to ensure that the material maintained the ductility needed for acceptable results at lower temperatures. Note: The material was "tested" prior to purchase and the reports did show lateral expansion results >80 (before 1400°F PWHT), and > 70 (after 1400°F PWHT). Thanks for any advice anyone may have in advance. Thank you.





RE: S41008 (410s) P7 PWHT Conditions?
RE: S41008 (410s) P7 PWHT Conditions?
metengr, what are your thoughts on using Low Carbon, 0.020% C Max. ER410NiMo instead of the E(R)410 filler? I also found the ER410 Filler to fail impacts miserably; however, using ER410NiMo yielded great results @ -50°F.
RE: S41008 (410s) P7 PWHT Conditions?
RE: S41008 (410s) P7 PWHT Conditions?
RE: S41008 (410s) P7 PWHT Conditions?
-20°F may be its lower limit.
According to ASME VIII DIv 1, UHA-51(e) - Exemptions from Impact Testing for welding procedure Qualifications. Impact testing is not required for the following combinations of weld metals and MDMTs except as modified in UHA-51(c):
UHA-51(e)(3) - for the following weld metal, when the base metal of the similar chemistry is exempt as stated in UHA-51(d)(3), then the weld metal shall also be exempt at MDMTs of -20°F and warmer:
(a) Austenitic Ferritic Duplex Steels;
(b) Ferritic Chromium Stainless Steels;
(c) Martensitic Chromium Stainless Steels.
Therefore, if the material is equal to or less than 1/4" thick and MDMTs of -20°F and warmer then impacts are exempt. Unfortunately, this is not the case for my qualification.
RE: S41008 (410s) P7 PWHT Conditions?
RE: S41008 (410s) P7 PWHT Conditions?
Read up on this material
http://www.aksteel.com/pdf/markets_products/stainl...