Industry News
316 vs 304 stainless steel screws: corrosion, cost and selection
2026-08-24
Compiled by JIALI Industrial (164.hk) — a Hong Kong fastener supplier specialising in screws, bolts, nuts and selection know-how.
Composition and corrosion
304 contains about 18% chromium and 8% nickel, fine for general humid use; 316 adds 2–3% molybdenum, greatly improving resistance to chlorides. In ASTM B117 salt-spray testing, 316 often lasts 2–4 times longer than 304 before rust appears — coastal outdoor, pool and marine jobs should choose 316.
Cost vs performance
316 raw material typically costs 30–50% more than 304, but replacement and maintenance are cheaper under heavy salt spray. For indoor equipment and general hardware, 304 is enough and offers the best value; upgrading to 316 pays off when service life and corrosion severity matter.
Selection tips and myths
Don't rely on the grade number alone: passivation and batch quality change real corrosion performance even within 304. In Hong Kong's humid, salt-laden coastal climate, exposed outdoor screws should be 316. Need 304 / 316 stainless steel screws in stock or material certificates? Contact JIALI Industrial (164.hk) with your application for fast selection.
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