JIS G4304 / G4312 SUS 321 Stainless Steel Composition & Titanium‑Stabilized Austenitic Properties
SUS 321 is a titanium‑stabilized austenitic stainless steel defined in JIS G4304 / G4312. With 17–19% chromium, 9–12% nickel, and titanium added to prevent carbide precipitation, it offers improved resistance to intergranular corrosion during welding and elevated‑temperature service. It is essentially a heat‑resistant upgrade to SUS 304.
321 performs reliably around 600°C, making it suitable for heat exchangers, exhaust systems, boiler components, furnace structures, and high‑temperature pressure equipment. It is preferred over standard 304 in applications involving frequent thermal cycling or long‑term medium‑to‑high temperature exposure.
SUS 321 is available as sheets, plates, tubes, bars, and strips. It is widely used in petrochemical plants, thermal‑processing equipment, and aerospace exhaust systems where both corrosion resistance and heat resistance are required.
321 performs reliably around 600°C, making it suitable for heat exchangers, exhaust systems, boiler components, furnace structures, and high‑temperature pressure equipment. It is preferred over standard 304 in applications involving frequent thermal cycling or long‑term medium‑to‑high temperature exposure.
SUS 321 is available as sheets, plates, tubes, bars, and strips. It is widely used in petrochemical plants, thermal‑processing equipment, and aerospace exhaust systems where both corrosion resistance and heat resistance are required.