Which filler metal classification is commonly used for 316 stainless?

• A. ER316L
• B. ER308L
• C. ER347
• D. ER309L

Answer: (A)

When welding 316 stainless, choose a filler metal that matches the base metal’s austenitic structure and corrosion resistance, with enough Mo to handle chloride environments and a low carbon content to prevent sensitization. The 316L filler metal fits perfectly because it has a similar nickel-chromium-molybdenum makeup and a reduced carbon level, which minimizes carbide precipitation in the weld and heat-affected zone. This helps maintain weld metal corrosion resistance and reduces the risk of intergranular corrosion in stainless steels exposed to chlorides. The other options are less suitable for typical 316: fillers intended for 304/304L lack sufficient Mo for optimal corrosion resistance in 316; stabilized fillers are chosen for specific carbide-forming situations and aren’t the standard for 316; and fillers aimed at high-temperature or dissimilar joints can alter the weld chemistry and aren’t necessary for a straightforward 316 weld.