TIG Stainless to Mild Steel
Posted: Tue Nov 21, 2017 11:18 am
Hello All:
I am new to TIG welding and the forum. I have been practicing on 1/8 stock and seem to be doing pretty well. I had the occasion to weld a Stainless Exhaust tip to 15-16 Gauge mild steel exhaust aluminized tubing. The Stainless tip seemed to be a slightly thinner at 16-18. It was a lap joint where the SS exhaust tip went over the steel exhaust tube. I practiced butt and lap welds on just the steel tubing (after grinding off the AL) and had no issues. The practice run was with ER70S2 1/16 rod and had the amperage at 60 amps but was not maxing out the pedal. I used 309L 1/16" rod on the steel to stainless. Both were 1/16 2% thoriated tungsten.
When I went to weld the real thing, I made a mess. The stainless would constantly burn through, but the mild steel would not puddle without more heat. I tried moving the heat to the thicker steel like I would with mig and as soon as I tried to wipe the puddle to the stainless, it would just melt and pull away. I tried multiple amperage settings and pulse, nothing seemed to work. It seemed I exceeded my current ability to tig weld. I did not back purge, but assumed with the steel backing the stainless I would not need to do so.
Any tips on how to complete a weld like this?
Drew.
I am new to TIG welding and the forum. I have been practicing on 1/8 stock and seem to be doing pretty well. I had the occasion to weld a Stainless Exhaust tip to 15-16 Gauge mild steel exhaust aluminized tubing. The Stainless tip seemed to be a slightly thinner at 16-18. It was a lap joint where the SS exhaust tip went over the steel exhaust tube. I practiced butt and lap welds on just the steel tubing (after grinding off the AL) and had no issues. The practice run was with ER70S2 1/16 rod and had the amperage at 60 amps but was not maxing out the pedal. I used 309L 1/16" rod on the steel to stainless. Both were 1/16 2% thoriated tungsten.
When I went to weld the real thing, I made a mess. The stainless would constantly burn through, but the mild steel would not puddle without more heat. I tried moving the heat to the thicker steel like I would with mig and as soon as I tried to wipe the puddle to the stainless, it would just melt and pull away. I tried multiple amperage settings and pulse, nothing seemed to work. It seemed I exceeded my current ability to tig weld. I did not back purge, but assumed with the steel backing the stainless I would not need to do so.
Any tips on how to complete a weld like this?
Drew.