the_jenny•3mo agoMost Upvoted

Had a flange weld crack on a boiler in Cleveland last month

Honestly, we were doing a hydro test on a new section at the old steel plant. The pressure was at 350 psi when we heard a pop and saw a hairline crack on a 12-inch flange weld. Tbh, we had to shut it down, grind out the whole weld, and redo it with a preheat this time. Has anyone else had a weld fail under test pressure and what was your fix?

3 comments

3 Comments

phoenix8453mo ago

Yeah, preheating and a slower cool-down fixed it for us too.

the_lee26d ago

Well I'll be, that lines up with what I was reading the other day. Bob from the welding supply shop mentioned thermal shock is the usual culprit with those big flanges, not just a bad weld. Said if you don't let the heat soak through evenly before you start, the metal will pull itself apart. He also said the slower cool-down keeps the grain structure from getting all brittle, which makes sense if you think about it. Good to hear it worked out for you too.

roberts.jesse3mo ago

Preheat for a 12-inch flange? That's standard practice, isn't it? Sounds like the first weld was just a bad one.