TYPE 409 STAINLESS STEEL is especially useful for applications requiring oxidation or corrosion protection beyond the capability of carbon steel and some coated steels. Current uses include automotive and truck exhaust systems, tubular manifolds, agricultural spreaders, gas turbine exhaust silencers, heat exchangers and fuel filters. This alloy provides good oxidation and corrosion resistance for automotive and non-automotive exhaust applications. AK Steel 409 ULTRA FORM Stainless Steel was created to meet more severe forming requirements than typical Type 409 and is particularly suitable for parts requiring more complex shapes and improved weldability.