I finally learned why my welds kept cracking on the pressure vessel

Last month I was working on a job at a chemical plant in Gary and kept having this problem with my welds cracking after cooling. I blamed the rod, blamed the machine, even blamed the cold weather. Then this old timer named Hank who's been doing this since the 80s came over and watched me for five minutes. He said I was moving too fast and not letting the puddle fill out. Told me to slow down by half and watch the color change before moving. I tried it and not a single crack since. Has anyone else had a simple fix like that change their whole approach?

2 comments

2 Comments

grace_fox31mo ago

Man, did your rod burn back at all when you were moving fast? I've had that same issue before on some thick wall pipe and it drove me nuts. Slowing down and watching that color change is the real trick, it keeps the puddle fluid enough to let trapped gasses out. Hank knew what he was talking about, I had a similar thing with a guy showing me to keep a tighter arc gap and it solved all my porosity problems. Sometimes the little adjustments are what make the biggest difference on pressure work.

park.adam1mo ago

240 amps on 6 inch schedule 80 is a different beast though, @grace_fox3. I found tightening the arc gap actually made the puddle too stiff on that thick wall for me, backing the rod out a hair let the gas escape way easier without the burn back nonsense.