Had a flange weld fail on a boiler at the old Miller plant in Akron

It was a 3 inch steam line, pressure was only at 150 psi. The root pass looked good but the cap cracked after a week. Now I always pre-heat past 250 degrees on any flange over 2 inches, no matter what the spec sheet says. Anyone else run into this with older carbon steel?

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3 Comments

holly8986mo ago

Actually, pre-heat temp depends more on material thickness than the flange size. That 250 might still be too low for thicker sections.

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fiona_walker146mo ago

We ran it at 300 for the heavy stuff.

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emma_burns965mo ago

Fiona, I read that and immediately felt called out because I tried the "set it and forget it" method once on some heavy wall pipe and my pre-heat was so low the welder laughed at me. Ended up having to grind out half my root pass and redo it while my foreman stood there sipping coffee judging my life choices. 300 sounds aggressive but honestly I bet your joints actually stuck together, which is more than I can say for my 200 attempt on 2 inch schedule 80.

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