in reference to tig welding

a friend of mine likes to weld mild with stainless rod simply because it comes out cleaner, and the stainless rod flows nicer when welding.

are ther any fatigue, cyclic heating, or other problems when using this combination on an exhaust part?

ALSO, what rod do you use for mild to stainless base welding?

 

I would like to know as well if there are any structural problems with using it.

A friend told me that 30+ year welder told him that it helps with impurities. I tried it and it works as he described.

But I do not want to use it if the strength is significantely less.

 

It defenitely flows better and looks nicer in the end...I agree with that, and admit I use it every now and then. The problem is the flexibility of the weld itself. 70-S2 filler(mild steel) actually flexes much more than the stainless filler does. The stainless filler is actually a stronger weldment, but at the same time is much less flexible and much more brittle...causing it to crack in high vibration areas(i.e. anything automotive really).
Hope this helped a little bit!
Kyle

 

anyone else have experience?

 

well it depend son how clean your mild steel is... with the stainless filler you can bring out the impurites with the mild

 

ALSO, what rod do you use for mild to stainless base welding?


Use 309L. It is also all I would recommend when welding on mild, if you want to do it with a different filler.
As mentioned above, hte weld will end up harder, and more brittle with stainless.
It should also be mentioned that the heat for the 2 materials can differ quite a bit, and using a ss filler when using mild steel heat is not the best for the stainless properties. Large difference in thermal conductivity is what dictates different heat settings.
If you really like stainless better, you couls use it on stuff that is statically loaded,
as mentioned, exclude almost anything automotive.