Welding Tips and Tricks

Sometimes when tig welding stainless I get these small circles in the middle of the root from refloating the metal. Any suggestions on how to stop this problem?

Even 308 has some silicon in it for scavenging. I believe what you're seeing is that silicon carrying the material it has picked up. The best fix is a thorough grind of the root pass (can be usefull for strict x-ray) but a real workout with a stainless wire wheel in a grinder should take care of most of it.

BTW, you'll still see little "swirlies" in the puddle from adding the rod in the next pass. Take care of it the same way.

This assumes I understood the question...

Steve S

After im done welding the root ill look inside the pipe. The root on the inside will look good except for a small circle usually on a tie in. Also after ive laid down my hot pass. Ill look inside the pipe and see the same blister looking circles on the root. I didnt get what u were saying on that last one.

That "blister" at the tie-in is where you've pushed a little silicon island to the tie-in, and it's solidified. It's basically glass. It's the nature of the beast. If you could reach the root with a wire-cup on a die grinder, it will vanish. It's not a flaw in the metal. It's material in the filler rod to capture impurities. If you've ever MIG welded with E70S-6, you'll see piles of these on every ripple of the weld.

Steve S

Ok I get what your saying. Ill try that die grinder trick tomorrow and let you know how it goes. Thank you for the help.