Boiler tube rolling torque specs are too loose these days

Honestly, I've been in this trade since 1998, and I've watched the recommended torque numbers on tube expanders creep down every few years. Ten years ago, we'd run a 3/4 inch tube to 47 ft-lbs and call it a day. Now the manual says 42, but I've pulled tubes on a 2019 retrofit that were barely holding at that low setting. The change came when the suppliers started pushing thinner wall alloys, and the new guys follow the chart over feel. I'm not saying ignore the specs, but if you're doing a retube in a plant like the one outside Gary, Indiana, add a quarter turn past the dial. Has anyone else noticed the tubes rattling loose after a hydro test with these lower numbers?

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2 Comments

spencer_gonzalez11mo ago

Bet those digital torque tools are lying, drift after a hot run.

5

charles8361mo ago

Man, that's rough. I feel you on the feel over the chart.

4