TIG Welding of stainless steel
In case a commercial welder decides to perform a TIG welding task with stainless steel on a stainless plate, there is a few things to consider. In case the welder tries to weld the two parts in a free state with no restraint, then at the end the plates will not be flat. Actually, the stainless steel will always warp when it is being welded. The role of the commercial welder here is to make everything possible for the distortion to be just to an acceptable level. In general, there are a few things that the TIG welder can do in order to minimize distortion when TIG welding stainless. The main thing is to make the puddle established as quickly as possible and get moving. The amperage should not be tapered any slower than needed.
It is a fact that the stainless steel has a low thermal conductivity, and the heat builds up quickly, so the TIG welding stainless quickly makes a difference in distortion. In case two aluminum fixtures have to be welded by the commercial welder, there will be a lot of welding required on each side. The base plates will most probably warp early, so the welder can react by clamping the base plates flat and tack welding them. As the welding is done, the welder can heat everything up reaching approximately 350 F for a few minutes and then one can let cool naturally before grinding the tack welds off. This will result in very flat aluminum base plates, after the processes of fast heating and slow cooling.
The TIG welder should accept that the stainless steel shall distort in the process of being weld. In fact, each metal distorts from using unevenly applied heat, however the situation with the stainless is worse than most other cases. The commercial welder should anticipate distortion and should also take steps to eliminate distortion, which is the key to the solution. In some cases, it is possible to remove the distortion after it occurs but is usually much better to prevent it if possible.