whats up with t-23 boiler tube? I just took a welding test on t-23 boiler tube coupon, in 6G position to qualify for a power plant outage scheduled soon. The problem is I failed the test, I've passed several tests using carbon steel and stainless steel. Why is this type tube so different to weld? The test was all GTAW weld procedure, the coupon was prepped, bevels cut and ID counter-bored and clean, all I had to do was clean up the coupon pieces as usual, flap wheel ID-OD and bevels. I took the bevel to a sharp edge at the ID as I always do for a tig weld test. I set the gap at 3/32", preheated to about 350 F. After running the root pass and looking at the inside of the tube, it was sure ugly! It looked like welding ss using the tig process and not having a purge gas (argon) on the inside of the tube. I asked QAQC if I could use a backing gas for this test and was told it isn't required. What am I doing incorrectly? I set up and welded this coupon (root only) just like I do for carbon steel 6G qualifying test, whats the differrence? I'd sure like to take this test again, but I want to know exactly what I need to do. I think this tube is used on the reheats tube panels, the coupon size is about 1-1/2" id x 2-1/2" od, maybe about a 1/2" wall. I've welded all my life, I'm 58 and have'nt had too much trouble being able to pass the various qualifying welding tests that I've done in the past. Does anyone know what I need to do differently to be able to make a proper weld on this t-23 type material?
Boilermaker
Re: Boilermaker
