For stainless steel, which filler metal is commonly used with GTAW or GMAW?

• A. ER308L with GTAW or GMAW.
• B. ER70S-6 with SMAW.
• C. ER4043 with SMAW.
• D. ER5356 with GMAW.

Answer: (A)

When welding stainless steel with TIG or MIG, you want a filler metal that preserves corrosion resistance and matches the alloy. For the common austenitic stainless like 304/304L, a stainless filler with low carbon is used to minimize carbide precipitation in the heat-affected zone. ER308L is the standard choice because it provides good corrosion resistance, ductility, and a composition that blends well with 304/304L base metal. Using this filler with GTAW or GMAW results in a weld that behaves similarly to the surrounding metal and is less prone to sensitization.

The other fillers shown are not suitable for stainless welding: those are steel or aluminum fillers, which would create mismatches in chemistry, properties, and corrosion resistance if used on stainless steel.