The TIG class

[GHarman]

Need more info

ASME P#5A preheat 3" on either side of center of joint min 350*, pref. 400*F. (on 9% Chrome)

What type of tube? Water Wall tubes, Preheat tubes, reheat tubes, pentents tubes, primary superheat tubes, Super heat division panels, super platen pentents, superheat front pentents, cool reheats, reheat rear pentants, reheat walls(front and side), hot reheat. etc. etc. Which tube set? GregH

 

[DValentine]

The tubes are 2. 5 inch . 220 wall thickness. We are tigging all the way out. We are using P-92 wire. We have been doing ok on the welds. My partner and I did not test on this material. We just ended up fixing a bunch of welds on the super heat platens, and moved on to some other repairs in the economizer. The last bunch of that material we welded was the spacer tubes and the feed lines to them. Conditions are not ideal. So at times we have fought the material, some times it goes great, other times not so much. The tubes are new, but we clean with a burr.

I have heard this is the first time in a boiler, that this material has been used... . so I hear. It is 9 chrome and has tungsten it. We have a controlled preheat and postweld heat treatment with ceramic heat pads. The interpass is 700 degrees. We let it cool to 500 and can weld again... sometimes only getting a 1/4 inch on the fill pass before it gets too hot. Post weld heat is 1425 degrees for one hour and then a slow ramp down.

We are running the root slowly. Looking each other in the best we can until we close the weld up. It is just interesting stuff and if everything is not "right" then it will not weld right. It has been a good learning experience.

Thanks for the help.

Dave

 

[GHarman]

Sounds like you got it under control, Dave. Wished I could be up there helping out:{. GregH