Switched up my grinder technique after a bad weld at the Flint plant

I was out at the Dow facility in Midland last month fixing a crack on a 12-inch pressure vessel. Always used a 4-1/2 inch grinder with a standard wheel for prep, but this old timer, Hank, told me to try a 7-inch with a flap disc instead. The difference in heat control was NIGHT and DAY, my weld came out way cleaner. Has anyone else had better luck switching grind sizes for boiler tube work?

2 comments

2 Comments

west.alice8d ago

Big grinder all the way. Dropping down to a 4-1/2 on boiler tube work builds up too much heat too fast. You'll get microcracks in the HAZ before you even know it. That old timer is right, the 7-inch flap disc spreads the heat way better, lets you take lighter passes. For pressure vessel work, I switched to a 9-inch with a 36-grit zirconia for initial cleanup then a 7-inch flap for feathering. Night and day difference on the final x-ray results. Just watch your speed with the big wheel, it'll grab and walk the cup right out of your hands if you're not careful.

riverp378d ago

Totally see this same thing with cars, too big a wheel is risky but too small burns up the tread.