Student TIG welding

vistin · Sat Oct 23, 2010 1:21 pm

I am a welding student that has a question about TIG welding aluminum. In my first TIG class I TIGed some 1/4 cupons together and tried to break the weld but it held. Then while it was cooling off the weld broke all the way down. Can you help me figure out what happened?
Thanks

sschefer · Mon Oct 25, 2010 5:55 pm

vistin wrote:I am a welding student that has a question about TIG welding aluminum. In my first TIG class I TIGed some 1/4 cupons together and tried to break the weld but it held. Then while it was cooling off the weld broke all the way down. Can you help me figure out what happened?
Thanks

Here's a guess.

I did that on a piece of 1/4 and was told it was because I didn't pre-heat and I didn't have enough current. I ended up overheating the aluminum and when it cooled it cracked the weld.

I was running 190amps and I should have been at around 210 and either pre-heated to 200 degrees or made some preliminary hot passes over it. I did the pre-heat, went up to 210 and I was able to increase my weld speed. I think that keeps the heat down on the piece and stops it from cracking.