Saw a steam drum repair on a 1950s boiler last week, still debating if welding was the right call

I was at a plant in Gary, Indiana last Thursday and watched a crew fix a steam drum on an old Keeler boiler from 1955. They opted to weld a patch over a crack instead of cutting out the whole section and replacing it. On one hand, the weld held during the hydro test at 150 PSI, and it saved the owner about 8 grand. But I keep thinking about stress risers over time and whether a full section replacement would have been safer. The lead guy said 'it'll outlast the rest of the boiler,' but I'm not sold. What do you all think, weld patch or full cut out for vintage drums?

2 comments

2 Comments

brian_murray26d ago

Hang on, they only hydro tested it to 150 PSI? On a 1950s boiler that was probably built to run at 150 or 200 PSI when it was new, maybe more. After 70 years of heat cycles that metal is tired. Testing it right at the operating pressure doesn't prove much. They should have bumped it up to at least 225 to see if that weld really holds when things get hot and the pressure spikes. I'd be nervous every time I fired that thing up.

carter.jennifer26d ago

Is there a chance the inspector was just going by the book for this specific setup? I agree with @brian_murray that 150 PSI feels like a bare minimum test for a boiler that old. Those old boilers were built tough, but after 70 years of heating and cooling, the metal gets brittle and can hide cracks. A proper hydro test should push it to 1.5 times the working pressure, at least, to give you some peace of mind that the weld won't let go when you're running it hot. I'd be asking for a written guarantee from whoever did that test before I'd stand near it.