Anything you do is going to be of limited success. It is just the nature of SS material (low thermal conductivity-high thermal expansion). What you are seeing is typical. You can attach chill blocks as heat sinks (though in my opinion more trouble than its worth), use pulsing (not an option really, if you don't already have the equipment) or use low parameters (as you have already surmised). But in the end its going to happen anyway. And in general it does nothing to interfere with the service life of the component. It just looks bad.
Keep in mind, consistent with other threads in the forum, that you may be adding more weld metal than needed. 16 gage, half couplings, this would be my guess.
Hello piperdolan, one thing did come to mind here as I was reading the original question again. You said that you were using a half coupling to weld onto the tube. Is this half coupling fitted to the radius of the tube or are you just filling the gap? Having a tightly fitted half coupling that matches the OD of the tube would help to somewhat minimize distortion also. Just a thought. Regards, aevald
Hi Piperdolan, would it be possible to drill a hole in the coupling, insert the tubing and then braze it
with silver solder (easyflow 45).
Thanks for responding, the half couplings are not fitted. I measured the gap and its 1/32 both sides. It looks like proper fitting, pulse arc maybe the way to go for me.THe half coupling is for a measuring sample line and catalytic substrate is pressed into the tubing, so any distortion from the half coupling causes problems in pressing that substrate in.thanks again for the response