Datasheet · Stainless
The three stainless grades you will choose between most often, with the corrosion, magnetism and cost trade-offs that actually decide the pick.
Stainless resists corrosion because chromium forms a self-healing oxide film. How much chromium — and whether molybdenum is added — decides which environment a grade survives, and that, not strength, is usually what drives the choice.
Composition & key properties
| Grade | Type | Key alloy | Yield (MPa) | Corrosion | Magnetic |
|---|
| 304 | Austenitic | 18Cr-8Ni | ≈ 215 | Good (general) | No |
| 316 | Austenitic | +2–3% Mo | ≈ 205–290 | Excellent (chloride) | No |
| 430 | Ferritic | 16–18Cr | ≈ 205 | Moderate | Yes |
How to choose
- Indoor, food, general purpose → 304, the default and most economical.
- Marine, medical, chemical, coastal → 316 for its molybdenum chloride resistance.
- Decorative, appliance trim, dry indoor, cost-sensitive → 430 (magnetic, cheaper).
- Welded and must stay corrosion-proof at the weld → specify 304L / 316L.
Fabrication notes
Stainless work-hardens and springs back more than mild steel, so we over-bend on the press brake and use nitrogen on the laser for a clean edge. After machining or welding we passivate to restore the oxide film.
Frequently asked questions
What is the real difference between 304 and 316?
316 adds 2–3% molybdenum, which sharply improves resistance to chlorides and pitting — that is why 316 is used for marine, medical and chemical parts, while 304 is fine for most indoor and food applications at lower cost.
Why specify 304L or 316L?
The L grades have lower carbon, which prevents carbide precipitation (sensitization) during welding. Specify L grades for welded parts that must keep full corrosion resistance at the weld.
Is stainless steel magnetic?
Austenitic grades (304, 316) are essentially non-magnetic; ferritic 430 is magnetic. Cold working can make austenitic grades slightly magnetic at edges.
Which stainless is easiest to machine?
Free-machining 303 is easiest but corrodes more; 304 and 316 are tougher on tools and work-harden, so we use sharp tooling and steady feeds to avoid glazing.
