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GMAW Sch 40 Stainless Socket Welds

10K views 31 replies 16 participants last post by  7A749  
#1 ·
Is there a procedure for single pass Mig welding schedule 40 socket welds for steam pipe? We will see up to 100 psi saturated steam pressure on this line.

I work for a small food manufacturer and our engineer brought in a contractor to install a new stainless boiler for our process. The pipe fitter assembled the associated piping in sch 40 stainless pipe with socket weld fittings. He seemed to have to chase a lot of leaks in a relatively small run of pipe with a lot of weld looking cold lapped. Is this an actual procedure that he just failed to perform properly (he never feathered his starts/stops so I believe that's most of his issue) or did they just throw this together?

I can't seem to find anything about GMAW on socket fittings and even came across a site where the process was not permitted. What's the deal? I feel like a lot more leaks are gonna arise in the coming months once we see some hot and cold cycling. They say they offer a lifetime warranty of the work but I wonder at what cost to our production schedule.

This is the worst joint but you can see others in the picture which I believe are also worrisome.

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Welder and settings it was left at.

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#7 · (Edited)
I've been questioning how their company makes money the whole time they were working our site. I could have built out the pipe myself in half the time it took their 2 guys to build it. There seems to be a skilled labor shortage in this area. They did use stainless wire and tri-mix gas. Welder looks set cold as well.

I worked around pipe welders all my life. I’ve never seen them use Mig on stainless steel socket welds.
Everywhere I’ve worked, that welder would be fired on the spot! But first drug out back and the sh!t beat out of him!
Agreed, I've heard SMAW and GTAW but never GMAW. When I asked why they were having so many leaks on such a short run their foreman kept blaming porosity and the fact they don't weld stainless often, usually carbon pipe with GMAW. Looks more like cold lap / lack of fusion to me. He did admit to testing out the process in house to determine if they could perform the job that way, which he found successful.

Yeah that's some pretty hack looking workmanship. Since it doesn't look like the people that did that job really knew what they were doing I'd have to wonder if most of those socket joints weren't fit up with the pipe "bottomed out" in them. I'd be sure and raise the subject of proper socket joint fit up with who ever is going to be redoing it.
Their welder was actually a great fitter, he just seemed to be led down the wrong road for the actual welding. He gapped his sockets correctly and built to plumb, level, square on the pipe stand. They chose Mig for speed and it just cost them time and money in the long run.
 
#5 ·
I worked around pipe welders all my life. I’ve never seen them use Mig on stainless steel socket welds.
Everywhere I’ve worked, that welder would be fired on the spot! But first drug out back and the sh!t beat out of him!
 
#6 ·
Yeah that's some pretty hack looking workmanship. Since it doesn't look like the people that did that job really knew what they were doing I'd have to wonder if most of those socket joints weren't fit up with the pipe "bottomed out" in them. I'd be sure and raise the subject of proper socket joint fit up with who ever is going to be redoing it.
 
#8 ·
It’s been so long now, aren’t you suppose to have a 1/16” plus gap from the pipe bottoming out on socket welds? :confused:
 
#9 ·
AWS does not offer a SWPS prequalified procedure for mig on stainless. But they do offer one for Tig, Er3xx alloys. Then produce a simple welder cert plate and have it tested and approved and you are downtown.

AWS Order # B2.1-8-212:2001(Revised2012) $186 member to $248 nonmember.
 
#10 ·
But this is pressure piping on a steam boiler; I guess it's almost certainly ASME code B31.X. ASME does not have any pre-qualified welding procedures; insofar as I know. So the contractor must have a weld PQR with test results and welder qualification for a GMAW stainless solid wire procedure. Anything else is not in compliance with code.

The welds look like short arc MIG and I'm not surprised at the leak issues; based on the visual appearance of the welds. Pipe that small is almost certainly easier to weld and get high quality results with TIG. But for pressure piping, the contractor still needs a PQR and welder qual record even for TIG. There's no getting around that if you need to be in strict compliance with the welding code.
 
#14 · (Edited)
Where are you located? Myself along with many others on this site could do this in our sleep and make it all perfect in both appearance and quality. People can die because of poor quality/craftsmanship when messing with steam at any pressure. I personally know a guy that was breaking a union loose to bleed off residual steam pressure and the union spun itself completely apart and what little pressure was still on the line cooked all the skin off his face. He was in up in the air and couldn't get away from it because he had his safety harness tied off. He wore a mesh sock on his face for two years. Please don't take steam at ANY pressure lightly, you'll meet your maker real quick or hope you did.
 
#16 ·
WOW !!! :eek: I did better than that when I started 40 + years ago. I would fire the guy that hired him.
A 100 pound STEAM line is nothing to f... with. :nono: I would have that contractor return and hydro test have to at least 200 PSI. Did they even test it ? They must have been less than the lowest bid. :laugh:
Any Union piping contractors will have real welders to do this. Socket welds are fun welds too !!!
 
#17 ·
This is the absolute easiest of the easy to weld right. I'd blackball that contractor for life. I once walked off a job working for a cheap *** contractor because he wanted us to stick weld some 1" schedule 40 for a mixing head in a chemical plant. I walked then they had another guy weld it and I heard it looked like a sprinkler system when hydro'd. They got run off then a real pipe contractor finished it up properly. Saving two dollars will cost you big bucks in these cases. Dumb a $$'s
 
#18 ·
WTF? This is a joke right?

That contractor should be run out of town. Were they trying to weld if with a Harbor Freight 110V unit? People can get killed doing $HIT work like that. My 10 year old would do a better job than that. The contractor blaming porosity? No? It's called incompetence. No offence but whomever hired them should be given the boot as well because they obviously have no clue what they are doing either to hire an incompetent contractor.
 
#20 ·
That's some pretty hack looking stuff. Even by my standards :laugh:

Really tho, I would find it hard to be taken seriously the second someone who knew what they were doing saw that mess. When I worked on the farm, a lot of stuff gets fixed that way, but many factors usually played into that. Usually lack of time for an in depth repair and everything being covered in cow shlt.

I let the more qualified ppl handle this one, and be thankful that my name isn't on that welding job lol.
 
#25 ·
These pictures need to be in the "welding fail" thread! Wtf is this crap?
 
#29 ·
I usually get the reverse, they want a "certified welder" to do it. When I question, "to what code do you want the certification" I get the blank stare... I do a lot of stuff for machine shops/machine building etc. Their customer wants some run of the mill machine weldment or whatever.
 
#30 ·
These guys are right. If doing stainless it needs to be tig. I have seen some shops wire stainless with hard wire but only on something that's no pressure. Looks like crap. And in that pic the heat is way low it's not tied in. And I agree that it probably is bottomed out on the fits which means they had no room for play to level and square up the fittings so they are probably out of spec. I need to go to work there I could be a #1 ace welder lol. On second thought they won't be in buisness long if they still are so scratch that.