Welding SS 304L and 316L

When fabricating gas piping for the fuel system, you may be supplied with flanges and piping of different grade Stainless Steel.

Pretty much the only difference between the two is that 316 has ~2.5% Moly, so you can definitely weld the two.

Since you're using the L (low carbon) versions of both grades, sensitization shouldn't be a problem, and therefore corrosion resistance and other properties of the weld metal should be at least equivalent to the 304 base metal. As far as welding the two together, they are practically interchangeable. You can get acceptable welds using all of the common stainless welding processes and with filler metal suitable for either base metal. You can weld 304L/316L with filler rod for either metal as long as the filler rod is “L”. If you don’t need the “L” either filler rod will still work.