Finally figured out why my welds kept cracking on that 3 inch pipe job

Honestly, I spent three days last month redoing root passes on a vertical seam at the refinery near Baton Rouge. Every single one cracked at the toe until my foreman pointed out I was letting the interpass temp drop below 350 degrees. Ngl, I felt like an idiot but now I always check with a temp stick before running the next bead. Has anyone else chased their tail over something this basic in the field?

3 comments

3 Comments

gavinw4518d ago

Three days on that same exact thing back in 2018. Interpass temp is one of those things you overlook until you're grinding out your fourth root pass at 2am. Fix that one variable and half your cracking problems just disappear.

margaret_kelly551mo ago

Wait, hold up, let me push back a little on this one. Absolutely making sure your interpass temp is right is important, no doubt about it. But I've seen welds with perfect heat control still crack because of the filler metal type or even just a tiny bit of wind messing with the gas shield on a root pass. Sometimes you can chase interpass temp all day when the real problem is the base metal itself, like if it's got high carbon or sulfur content that just throws off the weld puddle. Don't beat yourself up too bad over missing that temp stick check, there's usually a handful of things that can go wrong on a job like that.

oscarw831mo ago

Yeah I saw a write up from the AWS the other day that basically said the same thing. They had a study showing how even with perfect temps, high sulfur steel can turn your weld puddle into a runny mess no matter what you do. Its wild how much the base metal chemistry messes with things, especially on those old pipe jobs where you got no idea what the actual specs are. Makes me think the whole interpass temp thing gets way too much credit sometimes.

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