Stainless Steel
Stainless Steel 316 / 316L
Marine-grade austenitic. Mo addition gives chloride pitting & crevice resistance.
SS 316 is molybdenum-bearing austenitic steel. The Mo content (2–3%) gives significantly better chloride pitting and crevice corrosion resistance vs 304. Specified for marine, pharmaceutical, and any chloride-exposed service. 316L (low-carbon variant) for welded structures.
Equivalent Designations
| Standard | Designation |
|---|---|
| UNS | S31600 (316) / S31603 (316L) |
| Werkstoff Nr. | 1.4401 / 1.4404 / 1.4436 |
| JIS | SUS 316 / SUS 316L |
| BS | 316S31 / 316S11 |
| AFNOR | Z7CND17-11-02 / Z3CND17-12-02 |
| EN | X5CrNiMo17-12-2 |
Standards
ASTM A276 / A479 (bar)ASTM A240 (plate/sheet/strip)ASTM A312 / A213 (pipe / tube)EN 10088-3, DIN 17440
Chemical Composition (% by mass)
| C (316 / 316L) | 0.08 max / 0.030 max |
| Mn | 2.00 max |
| P | 0.045 max |
| S | 0.030 max |
| Si | 0.75 max |
| Cr | 16.0–18.0 |
| Ni | 10.0–14.0 |
| Mo | 2.00–3.00 |
| N | 0.10 max |
Mechanical Properties
| Tensile Strength | ≥515 MPa |
| Yield Strength (0.2%) | ≥205 MPa |
| Elongation | ≥40 % |
| Hardness (Brinell) | ≤217 HB |
Physical Properties
| Density | 8.0 g/cm³ |
| Melting Point | 1375–1400 °C |
Available Forms & Sizes
| Form | Size Range | Notes |
|---|---|---|
| Round Bar | Ø4 mm to Ø500 mm | — |
| Bright Bar | Ø4 mm to Ø100 mm | — |
| Hex Bar | 18 mm to 57 mm A/F | — |
| Square Bar | 18 mm to 47 mm | — |
| Flat Bar | 1/2″ to 10″ width × 2 mm to 150 mm thick | — |
| Plate/Sheet | 1.2 mm to 100 mm thick × 1000×2000 or 1250×2500 mm | — |
| Tube / Pipe | Seamless and welded, OD 6 mm to 1200 mm, wall 0.5 mm to 60 mm | — |
Use Cases
Marine fittings, propeller shafts, deck hardware
Mo content gives chloride pitting/crevice resistance vs 304. Specify for any saltwater or coastal service.
Surgical & implant — short-term only
316L cleared for short-residence implants (orthopaedic plates, screws). For long-term joint replacements, upgrade to ASTM F138 vacuum-melt grade or to titanium.
Pharmaceutical & bio-process vessels
Internal surface to BA finish or electropolished for cleanability.
Heat exchanger tubing
In chloride / brackish water service.
Design Notes
- 316L vs 316: use 316L any time the part will be welded and not solution-annealed afterwards (carbide precipitation around HAZ → intergranular corrosion). Otherwise 316 (slightly higher YS) is fine.
- Most common Indian fraud case: 304 sold as 316. Detection: PMI gun reads Mo content immediately. Spec the MTC + heat number with PMI verification on Aerospace tier.