Vacuum Outgassing Stainless Steel Welds

Date 02-09-2005 14:10

Anyone have any comments or experience on what weld process would be preferred to minimize outgassing of stainless steel welds in a fairly high vacuum (5 x 10-6 tor.) environment. I understand that GTAW maybe the best method, but may not be practical due to the large physical size and thickness of the structure to fabricate. (constructed of 1" w.t. 304L plate, 15 ft long). The weld is not the vacuum boundary, the entire weldment will be inside the chamber.
Construction Code: AWS D1.6.
Currently leaning towards a pulsed GMAW or smaller dia. SAW with a 308L filler material.

By metalcare (*)

Date 02-13-2005 19:32

You may try GMAW with inert gas shielding rather than SAW(sheilding with an inert gas reduces or eliminates oxygen entrainment and carbide precipitation, which cause outgassing) to fill the most of the weld groove and use one or more layers of cover passes with GTAW, which could yield better results.

Muthu
Leak Testing ASNT Level III