Im putting together a custom 3" downpipe and most of it is MILD steel but a few things i could only find in SS steel (5bolt flange, reducer, flex pipe). Can mild steel be mig'd to SS steel? Do i need a special gas or should i just turn up the heat and turn down the wire speed? Im using co2+argon and standard MIG wire.

Also I was gonna use fluxweld to tack it together- can SS and mild be fluxd together?

Thanks for any help, sorry for teh newbie questions

 

generally you want to use a higher grade filler metal than the base metal. I would use some stainless wire in your MIG if you have some. Mild wire will be fine Im sure though. Its just an exhaust. On the 5 bolt flange you probably want to weld short segments around it so you dont warp the flange. Maybe cool it with shop air between welds.

You set your wire speed and heat for good penetration and control just like if you were welding mild to mild.

Also for what its worth, most of the "stainless" flex joints i have seen actually have mild ends and stainless braid.

 

thank you very much, sorry i know these are real newb questions... If I got some SS wire could i still use the MIG for it with just the co2/argon mix?

 

ya, i did that last week with 75/25 since my other bottle (97/3) was empty. seemed to weld fine with the SS wire.

People will tell you to use argon, helium, co2 mix but you really dont need the helium unless its very thick metal or your welder is too weak. straight argon works too.

 

whats considered a good strength welder? i mean voltage/amp wise? thanks again!

Also do you think it can be done with non-SS wire or does it have to be SS? where can i purchase a small spool?

sorry for so many questions

 

I was looking to do this for someone, i wanted to weld SS and still be able to weld mild without changing the wire. Airgas (my gas suppliers) recommended 309 wire. Might work for you too, was never able to get my hands on it though

 

good info! thanks!

 

If you don't care about corrosion resistance, just use the mild wire and C25.