ferrous vs. Non ferrous header

[EclipticalGS]

Well, I sort of came across this as my friends mustang header cracked, i was looking at it and couldn't really tell what it was. I was sure the tubes were made out of Ferrous Stainless steel, but for some reason they had NO magnetic attraction at all?? Then, the flange part that bolts up to the head, was definately steel grade Ferrous metal, This part had a super amount of magnetic attraction.

The header pipes were not coated either. Well my question is, Did the manufacturer use different grades of steel and stainless steel?? What happened is a tube cracked away from the flange right at the bead...Why? because it rusted! that tell me that it was ferrous and contained high amounts of iron obviously. I have had stainless parts all my life, they never rusted.

So i was sort of messing around with my punishment downpipe and found that the actual Tubing was stainless steel but had no magnetic attraction, good for non rusting!, but then the flanges were very attractive?? Is this normal and from what i unsterstand, how easy it to weld these such metals together?!?

I mean, welding that non magnetic stainless steel tube, to a very magnectic steel flange, Isnt that a weak spot weld?? Or what welder should i use to bead and repair for him!

 

[Rob10_99]

Yes, SS flanges are pretty expensive.
The metallurgy is fairly close in Stainless and mild, they can be welded together just fine. Of course the weld will not be stainless unless its welding two SS pieces with SS rod/wire.
And it sounds like it was non SS rod/wire that was used to weld them together.

 

[EclipticalGS]

Thats what I thought! So, now that i know the tube is SS, and the flange is Mild, Would i weld with a mild steel rod then?? Just a quick rod welder/wire feed or w.e.?

Also, there is a lot of debate about SS, i almost consider it to be Non ferrous imho.

 

[jsawyer]

If i were you i would try to use some 309 to weld it its made just for welding mild steel to stainless

 

[EclipticalGS]

Thanks Jsawyer, just beaded it a couple mins ago!! Looks great.

 

[jsawyer]

your welcome that bead should'nt rust like the last one did 309 is stainless so the only thing you should have to worry about is that flange