ss socket weld purge?

Date 11-01-2009 02:17

Been doing alot of 3/4" 304 sch 40 socket welds. 3/32 308 filler, 2 passes= 3/16" and 1/4" fillet welds. running about 100 to 105 amps.
Would you guys recommend purging sch 40? Lower amps?
some of the welds I have to free hand because of valves or flanges. Most I walk the cup around.

By mooseye (**)

Date 11-01-2009 03:24

I have never used a purge with socket fittings. I don't see the need for it unless you are going to be getting the fitting hot enough to sugar through the heavy walls. Since the weld does not penitrate the joint, there is small chance of oxidation. I suppose if it were a very critical fitment, a purge might be an added saftey, but then you wouldn't use socket weld in a very critical application anyway.
I am not an expert and I don't play one on TV.

By mightymoe (**)

Date 11-01-2009 04:20

I got hung up when walking the cup on one and it sugared a little bit. Now I'm paranoid and want to purge everything. I guess I just need to be a better welder.
We have had some 2 1/2" sch 10 304 Socket welds come thru our shop. We always purge sch 10.
Worked mostly carbon, been welding ss for about three months, still learning every day.
Thanks for the reply.

By PipeIt

Date 11-02-2009 22:26

I agree with moose eye, plus most of your heat concentration will be on the fitting, anyway that's just my opinion.