Stainless Steel MIG Wire
Stainless steel MIG wire, selected by base grade and by service environment.
Grade selection
- 308L - the standard filler for 304 and 304L. The most common stainless MIG wire in general fabrication.
- 309L - higher alloy content, used for joining stainless to carbon steel and as a buffer layer on dissimilar joints. Using 308L on a stainless-to-carbon joint dilutes the weld metal below the alloy level it needs and produces a brittle, crack-prone result.
- 316L - molybdenum-bearing, for 316 base metal and anywhere chlorides are present. Marine, food processing and chemical service.
The L matters
The L designates low carbon. Lower carbon means less chromium carbide precipitation at the grain boundaries during the weld thermal cycle, which is what causes intergranular corrosion in service. On anything corrosion-critical, specify the L grade.
Shielding gas is not the same as on steel
Straight CO2 will not do. Stainless MIG needs a tri-mix or a low-CO2 argon blend, because carbon pickup from the shielding gas defeats the point of using a low-carbon wire.
Finish the job after the weld
The heat tint along a stainless weld is a chromium-depleted layer, and it will rust in service. Pickling paste or mechanical cleaning removes it. Use stainless-dedicated brushes and abrasives only - iron particles embedded from a mild steel brush rust and look like the weld has failed.
Free shipping over $175 across Canada. Counter pickup in North York.
