316 · UNS S31600 · W. Nr. 1.4401 · 316L · UNS S31603 · W. Nr. 1.4404 · 022Cr17Ni12Mo2
Stainless Steel 316 / 316L (S31600 / S31603): composition, properties, fittings and flanges
Types 316 and 316L are molybdenum-bearing austenitic stainless steels containing 16-18 % chromium, 10-14 % nickel and 2-3 % molybdenum. The molybdenum addition roughly doubles resistance to chloride pitting compared with 304 and gives better resistance to sulphuric acid, brine and organic acids. 316L limits carbon to 0.03 %…
- UNS
- S31600 / S31603
- W. Nr.
- 1.4401 / 1.4404
- Density
- 8.00 g/cm³ (0.289 lb/in³)
- Key strength
- 515 MPa / 75 ksi
Identification and standards
| Short form | 316 · UNS S31600 · W. Nr. 1.4401 · 316L · UNS S31603 · W. Nr. 1.4404 · 022Cr17Ni12Mo2 |
|---|---|
| Classification | Molybdenum-bearing austenitic stainless steel (low carbon grade available) |
| UNS | S31600 / S31603 |
| Werkstoff number | 1.4401 / 1.4404 |
| Material family | Stainless Steel |
Chemical composition
| Element | Composition (wt %) | Why it is there |
|---|---|---|
| Chromium (Cr) | 16.0 - 18.0 | Passive film, oxidation resistance |
| Nickel (Ni) | 10.0 - 14.0 | Austenite stability, toughness |
| Molybdenum (Mo) | 2.00 - 3.00 | Pitting and crevice corrosion resistance |
| Manganese (Mn) | 2.00 max | - |
| Silicon (Si) | 0.75 max | - |
| Nitrogen (N) | 0.10 max | - |
| Phosphorus (P) | 0.045 max | - |
| Sulphur (S) | 0.030 max | - |
| Carbon (C), Type 316 | 0.08 max | - |
| Carbon (C), Type 316L | 0.03 max | Low carbon prevents weld sensitisation |
| Iron (Fe) | Balance | Matrix |
Note Single figures are maximum limits unless shown as a range. Always confirm against the heat-specific EN 10204 3.1 certificate supplied with your order.
Mechanical properties
| Tensile strength, min, 316 | 515 MPa / 75 ksi |
|---|---|
| Tensile strength, min, 316L | 485 MPa / 70 ksi |
| 0.2 % yield strength, min, 316 | 205 MPa / 30 ksi |
| 0.2 % yield strength, min, 316L | 170 MPa / 25 ksi |
| Elongation in 2 in, min | 40 % |
| Typical hardness, annealed | 150 - 200 HB (approximately 80 HRB) |
| Recommended continuous service in air | Up to 870 °C for 316, 425-815 °C practical range |
Warning Values depend on product form, section thickness and heat treatment. Larger sections generally achieve lower strength than thin product; always design against the applicable code allowable stress rather than these figures.
Physical properties
| Density | 8.00 g/cm³ (0.289 lb/in³) |
|---|---|
| Melting range | 1371 - 1399 °C (2500 - 2550 °F) |
| Modulus of elasticity | 193 GPa (28 x 10⁶ psi) |
| Thermal conductivity at 20 °C | 16.3 W/m·K |
| Mean coefficient of thermal expansion, 20-100 °C | 15.9 µm/m·°C |
| Electrical resistivity at 20 °C | 0.74 µΩ·m |
| Magnetic behaviour | Non-magnetic when annealed |
Specifications by product form
| Pipe, seamless / welded | ASTM A312 / A358 / ASME SA-312 |
|---|---|
| Tube | ASTM A213 (boiler), A269 (general), A249 (welded) |
| Plate / sheet / strip | ASTM A240 / ASME SA-240 |
| Bar / rod / shapes | ASTM A276 / A479 / ASME SA-479 |
| Forgings & flanges | ASTM A182 Grade F316 / F316L / ASME SA-182 |
| Butt weld fittings | ASTM A403 / ASME SA-403 (WP316 / WP316L) |
| Forged / threaded fittings | ASTM A182, ASME B16.11, MSS SP-79 / SP-83 |
| Welding consumables | ER316L filler; use ER316LSi for improved wetting |
Product forms available
Hangbo supplies this grade in the following forms. Sizes outside the listed range can often be produced to order.
- Seamless and welded pipe to ASME B36.19M schedules
- Tube for heat exchangers, boilers and instrumentation
- Butt weld elbows, tees, reducers, caps and stub ends to ASME B16.9
- Forged flanges to ASME B16.5 Class 150-2500
Typical applications
- General chemical, petrochemical and process industry piping
- Food, beverage, dairy and pharmaceutical hygienic process lines
- Marine atmospheric exposure, coastal architecture and handrails
- Heat exchangers, condensers and evaporator tubing
- Pulp and paper mill piping, bleach plant auxiliaries
- Water treatment, desalination auxiliary piping and pump systems
Welding, forming and machining
- Welding
- Excellent weldability by all standard processes with ER316L filler. Control heat input and interpass temperature to around 150 °C; use low carbon filler and avoid sensitising in the 425-815 °C range where exposed to a corrosive service afterwards.
- Heat treatment
- Solution anneal at 1010-1120 °C followed by rapid cooling. Stress relieve at 480-620 °C only when the subsequent service is not sensitising.
- Machining
- Standard austenitic practice: sharp tooling, positive rake, adequate feed below the work-hardened layer and generous coolant.
- Service limits
- Avoid stagnant chloride solutions above roughly 50 °C and high chloride levels, which cause pitting and stress corrosion cracking. Upgrade to duplex 2205, super austenitic or nickel alloy when chloride content is high.
Buy Stainless Steel 316 / 316L from Hangbo
Material is supplied with full heat-number traceability, solution annealing or ageing performed under calibrated furnace control, and an EN 10204 3.1 certificate covering chemical analysis, mechanical properties, heat treatment records and the agreed NDT scope. Positive material identification and third party inspection and test reports from SGS are available for critical service.