JIS G4304 / G4312 SUS 303 Stainless Steel Composition & Free‑Machining Austenitic Properties
SUS 303 is the free‑machining austenitic stainless steel grade in JIS G4304 / G4312. With elevated sulfur content, it provides excellent machinability for turning, drilling, and threading, making it a classic free‑machining stainless steel.
It is widely used for bolts, nuts, gears, shafts, valve components, and electronic hardware. Corrosion resistance is slightly lower than SUS 304 but sufficient for general atmospheric environments. SUS 303 is supplied mainly as bars, wires, and selected plate forms. It is ideal for machining‑intensive applications requiring high efficiency and good surface finish.
It is widely used for bolts, nuts, gears, shafts, valve components, and electronic hardware. Corrosion resistance is slightly lower than SUS 304 but sufficient for general atmospheric environments. SUS 303 is supplied mainly as bars, wires, and selected plate forms. It is ideal for machining‑intensive applications requiring high efficiency and good surface finish.