Changed my mind about pre-heating on the big retrofit in Toledo

I was working on the old coal boiler retrofit at the power plant there last fall. The foreman insisted we pre-heat the new economizer sections to 250 degrees before welding, which I thought was overkill for the schedule we had. After three days, we had zero cracks on the pressure welds, while the crew on the other unit that skipped it had to redo four major seams. The extra six hours up front saved us two full days of repair work. Anyone have a different method that works just as well without the big heat rig?

2 comments

2 Comments

flores.tessa17h ago

We had a similar spec on the turbine casing at the Pine Bend refinery last year. The procedure called for a 200-degree preheat with ceramic blankets, and it felt like a waste of a whole shift. But after seeing the other crew fight with stress cracks all week, I got it. Sometimes the book is right, even when it hurts the schedule.

cameron76313h ago

Ever try a lower temp but hold it longer? I've heard some crews get away with 150 degrees if they soak the joint for a full shift before the weld.