Welding mild steel to stainless

[MrBlobby]

I'm creating a 4 into 1 exhaust, made up of a mild steel header and stainless link pipe. Rather than having a slip-on joint at this union, would it be OK to MIG the two steel types together using Argon/Co2 and mild steel wire?

The completed system is to be painted.

 

[pedrobedro]

I've done it and it works if you're not bothered what it looks like. It will rust though.

 

[Charred fingers]

I believe you can also use 309 stainless wire to
weld dis-similar metals using 95/5 argon co2
but would be expensive for one off.

 

[MrBlobby]

Yes I've been looking at the prices of stainless wire
I'm gonna using Argon/Co2 and mild steel wire, and hope for the best. I'm not bothered about rusting because the whole system will be painted as soon as I've smoothed the welds.

Cheers
Steve

 

[SamT]

yeh ive welded stainless rear box to a mild steel system using mild steel wire

also welded stainless to stainless with mild steel wire

 

[Hitch]

This has been covered many times here.

It will weld. But isn't the ideal. It may well fail before the rest of the system.

If its a safety critical weld, dont even consider doing it.

The ideal solution in such a job would be to use 309stainless wire, which is for dissimilar metal.

 

[matt1978]

yeh ive welded stainless rear box to a mild steel system using mild steel wire

also welded stainless to stainless with mild steel wire

Why did you bother using Stainless steel in the first place?