316L Stainless Steel (UNS S31603)
Austenitic (low carbon, Mo-bearing) · ASTM A240/A240M · Density 7.98 g/cm³
316L (UNS S31603) is a low-carbon austenitic stainless steel with 2–3% molybdenum, giving it far better resistance to pitting and chloride corrosion than 304. The low carbon prevents sensitization during welding, making it the standard grade for marine, chemical and pharmaceutical service.
Chemical Composition (wt%)
| C | Mn | Si | Cr | Ni | Mo | P | S |
|---|---|---|---|---|---|---|---|
| ≤0.030 | ≤2.00 | ≤0.75 | 16.0–18.0 | 10.0–14.0 | 2.00–3.00 | ≤0.045 | ≤0.030 |
Single values are maximums unless a range is shown. Balance: Fe. Per ASTM A240/A240M.
Mechanical Properties
| Tensile strength | ≥485 MPa (70 ksi) |
|---|---|
| Yield strength (0.2%) | ≥170 MPa (25 ksi) |
| Elongation (50 mm) | ≥40% |
| Hardness | ≤217 HBW |
Room-temperature minimum values are summarized for annealed flat product under ASTM A240/A240M unless a condition is named in the property label; product form and thickness can change the requirement.
Physical Properties & Structure
| Density | 7.98 g/cm³ |
|---|---|
| Magnetic response | Essentially non-magnetic after solution annealing; cold work can introduce a measurable magnetic response. |
| Microstructure | Austenitic (low carbon, Mo-bearing) |
Corrosion Resistance & Limits
- General corrosion resistance comes from the chromium-rich passive film; nickel, molybdenum, nitrogen and copper change performance by grade.
- Check chlorides, temperature, crevices, deposits, process chemistry and cleaning conditions. A grade designation alone is not a service-life guarantee.
Fabrication & Heat Treatment
| Welding | Generally weldable with a qualified procedure and matching or over-alloyed filler where required; remove heat tint when corrosion service demands it. |
|---|---|
| Forming | Good ductility is typical, but rapid work hardening increases forming load and springback; bend radius and intermediate annealing depend on grade and reduction. |
| Machining | Use rigid tooling, positive feeds and controlled heat because the material work-hardens; free-machining grades require separate corrosion and welding review. |
| Heat treatment | Solution annealing and rapid cooling restore the intended condition where applicable. Austenitic grades are not hardened by conventional quench-and-temper treatment. |
Equivalent Grades
The closest international equivalents of 316L Stainless Steel are 1.4404 (X2CrNiMo17-12-2) in the EN system, SUS316L in the JIS system, 022Cr17Ni12Mo2 in the GB system.
These are common corresponding designations, not unconditional substitutes. Verify chemistry, mechanical properties, product standard, delivery condition, dimensions and project approval before changing designation.
| System | Designation |
|---|---|
| UNS | S31603 |
| EN | 1.4404 (X2CrNiMo17-12-2) |
| JIS | SUS316L |
| GB | 022Cr17Ni12Mo2 |
Reference Product Forms & Dimensional Ranges
Common reference product forms for 316l stainless steel: Sheet / Plate, Coil / Strip, Pipe / Tube, Bar.
| Finishes | No.1, 2B, BA, No.4, hairline, 8K mirror |
|---|---|
| Sheet / coil thickness | 0.3–6.0 mm |
| Plate thickness | 6–80 mm |
Common surface and delivery options: No.1, 2B, BA or mechanically polished finish when supported by the product route; Annealed and pickled, descaled or polished tube finish as specified; Hot rolled, peeled, bright drawn, ground or polished bar condition according to tolerance.
These published ranges are engineering references, not a live-stock or production-capability promise. Confirm the required product form, dimensions, condition, finish and supply route in the quotation.
Typical Applications
- Boat fittings and coastal structures
- Chemical tanks and process piping
- Pharmaceutical process equipment
- Food industry in salty environments
316L Products We Export
316L Stainless Steel Sheet
316/316L stainless steel sheet for marine and chemical service, in quotation-confirmed dimensions in 2B, BA and brushed finishes, cut to size, with ordered documentation.
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316L Stainless Steel Seamless Pipe
Seamless 316L stainless steel pipe to ASTM A312, in quotation-confirmed NPS and schedule, pickled and annealed, with ordered documentation — for chemical, marine and process service.
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Frequently Asked Questions
What is the difference between 316 and 316L?
Carbon content: 316 allows up to 0.08%, 316L up to 0.030%. The low-carbon version resists sensitization when welded, keeping the heat-affected zone corrosion resistant. Strength minimums are slightly lower for 316L, which rarely matters in practice.
Will 316L rust in seawater?
316L performs well in marine atmospheres and splash zones, far better than 304. In permanently immersed, stagnant or high-chloride conditions it can still pit over time — for those cases consider duplex 2205 or super austenitic grades.
Is 316L suitable for pharmaceutical and food equipment?
Yes. 316L with a fine surface finish (2B, BA or electropolished) is the default material for pharmaceutical process equipment and high-end food machinery because of its cleanability and corrosion resistance.
316L Compared With Other Grades
Organizational author: Tsingshan (Shandong) Iron & Steel Co., Ltd..Review method, status and limitations.
Other stainless steel grades:
304304L316201321310S4104302205202301309S316Ti347904L409L4204394414442507303317L254 SMO440C17-4 PH2304
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