GTAW/SMAW welding of F22 (over 22mm) with pwht and subsequent Inconel 625 overlay. B31.3 would like 704-760degC hold temp. but Inconcel cladding?? Trying to get good impact values @ -46degC (>=42J). Is this possible w/ pwht @ approx. 640degC? Would ER80S-D2/E10018-D be ok? Any help appreciated!