About 321|Titanium-stabilized austenitic stainless. Same base composition as
304 but with titanium added to prevent chromium carbide precipitation during welding and high-temperature service (800-1500°F). This eliminates intergranular corrosion in the heat-affected zone without requiring the low carbon content of
304L. Used for welded structures that operate at elevated temperatures: exhaust manifolds, expansion joints, and chemical processing equipment. Machines like 304 with the same work-hardening and chip control issues. Compare to 304L (low carbon approach to the same problem) and
347 (niobium-stabilized, same concept with a different stabilizing element).
