JIS G4304 / G4312 SUS 329J3L Stainless Steel Composition & Duplex Corrosion‑Resistant Properties

SUS 329J3L is a duplex stainless steel defined in JIS G4304 / G4312. With about 25–26% chromium, 5–7% nickel, molybdenum, and nitrogen, it combines ferritic and austenitic phases, offering twice the yield strength of austenitic grades and superior pitting resistance.

It is widely used in seawater systems, chemical plants, pressure piping, storage tanks, heat exchangers, and chloride‑rich environments. Weldability is good, and duplex balance remains stable after welding. SUS 329J3L is supplied as plates, tubes, bars, and profiles. It is a cost‑efficient duplex alloy for marine engineering, chemical equipment, and high‑strength structural applications.