Composition & metallurgy

Typically about 10.5–30% chromium with low carbon and controlled interstitials. Some grades use molybdenum, titanium or niobium stabilization.

Common grades

409, 430, 439, 441 and higher-chromium ferritic grades such as 444.

Applications

Automotive exhaust systems, appliances, decorative trim, heat exchangers, hot-water equipment and architectural applications.

Engineering characteristics

Magnetic, generally not hardenable by conventional heat treatment, and often less ductile than austenitic grades. Weldability and toughness vary substantially with chromium/interstitial content and section thickness.

Known manufacturers

Major stainless producers include Outokumpu, Acerinox, Aperam, POSCO, Jindal Stainless, Tsingshan and TISCO/Baowu.

Specification checks

Confirm the current standard revision, exact product form, heat-treatment condition, mechanical properties, impact requirements where applicable, corrosion environment, welding procedure, dimensions, tolerances, NDT and mill test certification. Similar designations across standards are not automatically equivalent.

Element Folio engineering reference. Manufacturer examples are indicative and product availability changes by plant, region and year.