ASTM A240 347 Stainless Steel Composition & High‑Temperature Stability
ASTM A240 347 (UNS S34700) is a niobium‑stabilized austenitic stainless steel grade under ASTM standards. With 17–19% chromium, 9–13% nickel, and niobium added in proportion to carbon content, it prevents carbide precipitation during welding or elevated‑temperature service, improving resistance to intergranular corrosion.
347 offers superior structural stability at temperatures between 600–850°C, making it suitable for heat exchangers, exhaust systems, boiler components, furnace structures, and high‑temperature pressure equipment. It maintains good weldability and does not require post‑weld heat treatment.
347 is supplied as sheets, plates, tubes, bars, and strips. As a heat‑resistant upgrade to the 304 family, it provides reliable performance in high‑temperature and welded applications across petrochemical, thermal‑processing, and aerospace industries.
347 offers superior structural stability at temperatures between 600–850°C, making it suitable for heat exchangers, exhaust systems, boiler components, furnace structures, and high‑temperature pressure equipment. It maintains good weldability and does not require post‑weld heat treatment.
347 is supplied as sheets, plates, tubes, bars, and strips. As a heat‑resistant upgrade to the 304 family, it provides reliable performance in high‑temperature and welded applications across petrochemical, thermal‑processing, and aerospace industries.