Not logged inAmerican Welding Society Forum
Forum AWS Website Help Search Login
Up Topic Welding Industry / Technical Discussions / 904L Backing Gas
- - By magnolrr Date 12-04-2019 13:13
Hi everyone.My Name is Magno Rodrigues, I'm new here. I would like your help to solve a question.
As we know, some people use nitrogen instead of argon as a backing gas on stainless steel 304, 316 welding
In case of 900 series, 904l specifically, the WPS order to use a 100% purity argon.
I have read some articles, but not about the situation above.
My question is: Can be used nitrogen istead of argon to purge 904l Stainless Steel? If not, Why?
Parent - By jwright650 (*****) Date 12-04-2019 13:24
Look through this old thread here in the forum and see if this answers your question.
Parent - By Jim Hughes (***) Date 12-05-2019 16:26
To answer your question directly, if your procedures have been qualified to ASME Sec. IX using argon then the answer is no. You would have to requalify using Nitrogen backing. From a welding standpoint, since 904L is a true austenitic stainless steel with low carbon content and has a full austenite grain structure in the annealed product form, using nitrogen would be acceptable with client concurrence. N2 could help improve corrosion resistance and pitting resistance. There are a number of papers on this. I think you could find them on TWI web site.
- By 803056 (*****) Date 12-04-2019 17:43
This link takes to a guide published by a major supplier of stainless steels. It may be useful.

Nitrogen is not an inert gas. It may combine with nickel as an interstitial alloying constituent.

Up Topic Welding Industry / Technical Discussions / 904L Backing Gas

Powered by mwForum 2.29.2 © 1999-2013 Markus Wichitill