[dewdrop9]

I was just wondering if you can weld aluminum and stainless steal to each other and what kind of tungsten and filler rod you would need

[Otto Nobedder]

That'd be a "no".

They make transition pieces, one side stainless, one side aluminum, so you CAN join the two metals. I've used them joining 304 with 6061-T6 (this was for pipe... don't know about structural sections). There is a temperature limit, and the piece comes with an attached non-resetting thermometer strip to tell you the ultimate temp you've reached at the critical part of the joint.

I suspect it's a high-precision interference fit, with the aluminum sleeved inside the stainless, with the aluminum pre-shrunk in liquid nitrogen, and excess temps de-temper the aluminum and ruin the joint.

[dewdrop9]

Ok Steve so what if i wanted to weld stainless to steel would that work because you would use DC like you would use for both?

[Otto Nobedder]

Ok Steve so what if i wanted to weld stainless to steel would that work because you would use DC like you would use for both?

Yes, indeed.

ER309 is specifically intended for welding carbon steel to stainless steel, and is done DCEN just like carbon steel.

Steve S

[dewdrop9]

ok steve but what if i wanted to do the same with a mig welder what would i need to do that i got a millermatic 252 at school that i can use what would you or anyone else recommend?

[Fat Bob]

309/309L Stainless Steel MIG Welding Wire.

[Otto Nobedder]

309/309L Stainless Steel MIG Welding Wire.

And if you have it available, stainless MIG looks better (and welds hotter) with tri-mix than with 75/25.

Steve S

[NYWELDERJim]

Steve,

Can you elaboarte on tri-mix gases? If have heard several welders refer to them. What gases are blended together in what ratios for what materials? How much benefit does a tri-mix of gases provide? Thanks!

Jim

[dewdrop9]

thanks steve you really know you stuff

[Otto Nobedder]

"Tri-mix" gas for stainless steel MIG usually refers to 90% helium, 7.5% argon, and 2.5% CO2.

"Tri-mix" can actually mean many things in the welding world, though.

Sad it's not standardazed...

Steve S

[NYWELDERJim]

Thanks Steve. I saw in someone's recent post a statement abut a tri-mix tungsten. As if this welding technology wasn't complicated enough!