Today I am tig welding stainless steel nuts onto stainless plate flanges.
I know from experience that if I try to weld these parts in free state without some type of restraint, that the plates will not be flat when I am done.
Stainless warps when you weld it. Period.
All you can really hope to do is limit the distortion to an acceptable level.
There are a few things you can do to minimize distortion when tig welding stainless and the main one is to get the puddle established as quickly as possible and get moving.
Get in...weld....get out. dont taper amperage any slower than needed.
Since stainless steel has a low thermal conductivity, heat builds up quickly so tig welding stainless quickly makes a difference in distortion.
But sometimes there are other ways to limit distortion..
whenever I have multiple parts to weld like in this video...a flat part with several welds on one side..., I try to clamp them together ....back to back.
I welded 2 aluminum fixtures a while back where there was quite a bit of welding required on one side only. I saw the base plates warping early on so I decided to clamp the base plates flat and tack weld them.
After welding, I heated everything up to around 350f for a few minutes and let cool naturally before grinding the tack welds off.
It worked great.
After heating and slow cooling, The aluminum base plates were very flat.
so on this little stainless job, the flange plates had bolt holes as part of the design.
All I needed ot do was bolt it together , weld all the nuts...let cool, and remove bolts.
Stainless steel distorts when you weld it. It just does. Every metal distorts from unevenly applied heat, but stainless is worse than most.
Anticipating distortion, and taking steps to eliminate distortion is the key.
Sure, sometimes, its possible to remove distortion after it occurs but is usually way better to prevent it.
So whenever you have multiple parts to weld and you can clamp, bolt, or tack weld 2 of them together where distortion and stresses of each part opposes the other , it can really make a difference in keeping things flat and straight.
So whenever you are tig welding stainless, remember...get that puddle started quickly...get moving ...get out. Once heat builds up, its hard to outrun the heat.