Welding SS304 Materials

Try some and see what works I have absolutely no knowledge of this subject. But since when does that stop my advice being given any way.

Very commendable. Thank you.

You know, I think you should run for public office. Then, you wouldn't have to merely give advice; your every whim on any subject whatsoever, no matter how removed from your experience or knowledge, would become law!

I'm guessing you already know that AWS E/ER 308, 308L and 347 are more typical. Why do you want to use ER309; is it because you have it handy? Are you welding with Ar/CO2 instead of helium?

You can use RT347 filler wire for welding of SS304 material.

As you rightly pointed out, ER 309 is used to weld SS 309 as well as SS304 to CS.

Since ER 309 contains 25Cr & 12 Ni as extra elements aprat from C, Mn, Si and using it on SS 304 containing 18 Cr & 8 Ni in addition to same level of C, Mn & Si will not be cost effective in production welding. Other wise it will not harm the metallurgical structure of the base metal. At the same time it should not be other way reound , i.e., ER 304 should not be used on SS 309 on same above reasons. .

It is in the same family as 304 with a higher Chromium and Nickel content by a few percentage points. I have been told it is not recommended but I have used it on several occasions with no problems. Particularly where there has been abrasive wear (my answer to hardfacing stainless)