316 steel (S31600): properties, composition, equivalents
316 stainless steel (UNS S31600) and 316L (S31603): 16–18 % Cr, 10–14 % Ni, 2–3 % Mo. 205 MPa (30 ksi) yield, 515 MPa (75 ksi) tensile, PREN ≈ 24, the marine grade. Composition, properties, 316 vs 316L vs 304, 1.4401/1.4404 equivalents.
What is 316?
Type 316 is the second most common stainless steel and the first choice where 304 pits: an 18-8 austenitic base with 2–3 % molybdenum and 10–14 % nickel, UNS S31600 (316) or S31603 (316L, carbon ≤ 0.03 %). Molybdenum raises the pitting resistance equivalent from about 18 to 24, which is the difference between tea-staining and staying bright in coastal air, de-icing salt, brackish water and most acidic process streams. That is why 316 is called 'marine grade' and why A4 stainless fasteners, boat fittings, pharmaceutical equipment and chemical piping are made from it.
Mechanically 316 is a twin of 304: 205 MPa (30 ksi) yield and 515 MPa (75 ksi) tensile minimum, 40 % elongation, non-magnetic, no low-temperature transition, hardenable only by cold work. It is slightly stronger than 304 at elevated temperature and has better creep resistance; 316H is the creep-rated version above 525 °C.
Most coil, plate and pipe today is dual-certified 316/316L — carbon ≤ 0.03 % with the higher 316 strength minimums — so a specification for either is normally satisfied by the same stock. EN 1.4401/1.4404, JIS SUS316/316L and GB 06Cr17Ni12Mo2 are identical for procurement; the table also grades the high-Mo (1.4436) and Ti-stabilized (1.4571) European variants.
316 chemical composition
| Element | Mass % | Note |
|---|---|---|
| C | ≤ 0.08 | 316L (S31603): ≤ 0.030; 316H (S31609): 0.04–0.10 |
| Mn | ≤ 2 | |
| P | ≤ 0.045 | |
| S | ≤ 0.03 | |
| Si | ≤ 0.75 | |
| Cr | 16 – 18 | |
| Ni | 10 – 14 | |
| Mo | 2 – 3 | |
| N | ≤ 0.1 |
ASTM A240/A240M-22 Table 1 (S31600 / S31603). Compare EN 1.4401 (316): Cr 16.5–18.5, Ni 10–13, Mo 2.0–2.5, C ≤ 0.07; EN 1.4404 (316L): same with C ≤ 0.030.
316 mechanical properties
| Thickness / condition | Yield strength ReH / Rp0.2 MPa (ksi) | Tensile strength Rm MPa (ksi) | Elongation A % | Hardness |
|---|---|---|---|---|
| 316 plate/sheet/strip — annealed (A240) | ≥ 205 (≥ 29.7) | ≥ 515 (≥ 74.7) | 40 | ≤ 217 HB / ≤ 95 HRB |
| 316L plate/sheet/strip — annealed (A240) | ≥ 170 (≥ 24.7) | ≥ 485 (≥ 70.3) | 40 | ≤ 217 HB / ≤ 95 HRB |
| 316 bar — annealed (A276) | ≥ 205 (≥ 29.7) | ≥ 515 (≥ 74.7) | 40 | — |
| 316 bar — cold finished ≤ 12.7 mm (A276 cond. B) | ≥ 310 (≥ 45.0) | ≥ 620 (≥ 89.9) | 30 | — |
| TP316 pipe (A312) | ≥ 205 (≥ 29.7) | ≥ 515 (≥ 74.7) | 35 | — |
| 316 at 300 °C (typical Rp0.2) | ≈ 140 (≈ 20.3) | ≈ 430 (≈ 62.4) | — | — |
Minimum values, ASTM A240 Table 2 / A276 Table 2. Typical annealed 2B sheet: yield 270–310 MPa, tensile 580–620 MPa. Dual-certified 316/316L material meets the 316 minimums with 316L carbon.
Impact toughness
316 requires a minimum Charpy V-notch energy of 100 J at -196 °C (typical). Austenitic — no transition; used for cryogenic and LNG service (316L preferred).
316 equivalent grades
| Grade | System | Match | Why / differences |
|---|---|---|---|
| 316S31 / 316S11 | BS (superseded British) | Identical | BS 1449 designations for 316 / 316L. |
| 1.4401 | EN (European) | Identical | X5CrNiMo17-12-2: Cr 16.5–18.5, Ni 10–13, Mo 2.0–2.5, C ≤ 0.07 — within the 316 window (Mo at the low end). |
| 1.4404 | EN (European) | Identical | X2CrNiMo17-12-2 = 316L: C ≤ 0.030, Mo 2.0–2.5. Dual-certified 1.4404/316L is the norm. |
| 06Cr17Ni12Mo2 / 022Cr17Ni12Mo2 | GB/T (China) | Identical | GB/T 20878 (formerly 0Cr17Ni12Mo2 / 00Cr17Ni14Mo2). |
| SUS316 / SUS316L | JIS (Japan) | Identical | JIS G4304 SUS316: C ≤ 0.08, Cr 16–18, Ni 10–14, Mo 2–3. |
| 1.4436 / 1.4432 | EN (European) | Near | Mo 2.5–3.0 % versions (316 / 316L 'high-Mo') covering the upper half of the ASTM Mo range. |
| 1.4571 | EN (European) | Near | 316Ti — Ti-stabilized; equivalent corrosion class, better at 400–550 °C. |
| 08Kh17N13M2T / 03Kh17N14M3 | GOST (Russia/CIS) | Near | GOST 5632 Mo grades; 10Kh17N13M2T (Ti-stabilized) is the common Russian 316 equivalent. |
| 304 | AISI / SAE | Functional | Non-Mo 18-8: same strength and formability, PREN 18; substitute where chlorides are absent. |
| 2205 | AISI / SAE | Functional | Duplex S32205: double the yield, PREN 35 — the upgrade for warm chloride service. |
| 17-4 PH | AISI / SAE | Functional | Austenitic: similar corrosion resistance, one-quarter of the yield strength; 17-4 replaces it where strength matters. |
Identical = same composition and mechanical limits within rounding. Near = one limit differs (e.g. carbon max or impact temperature). Functional = interchangeable for most uses after an engineering check. Full cross-reference for 316 →
Old and superseded designations
| Old name | Standard | Note |
|---|---|---|
| S31600 / S31603 / S31609 | UNS | 316 / 316L / 316H. |
| 316Ti (S31635) | ASTM A240 | Titanium-stabilized variant; EN 1.4571 — rarely stocked in the USA. |
| CF8M / CF3M | ASTM A351 / ACI | Cast equivalents of 316 / 316L. |
| 316S31 / 316S11 | BS 1449 / BS 970 | 316S31 = 316, 316S11 = 316L. |
| A4 | ISO 3506 (fasteners) | A4-70 / A4-80 stainless bolts are 316-class. |
Product forms and tolerance standards
Product forms: sheet, strip and plate (ASTM A240), bar and shapes (A276, A479), seamless and welded pipe (A312 TP316/TP316L), tube (A269, A249), fittings (A403 WP316), flanges and forgings (A182 F316), wire, fasteners (F593 Group 2), castings CF8M / CF3M (A351).
Dimensional tolerances: sheet/plate: ASTM A480; bar: ASTM A484; pipe: ASTM A999 / ASME B36.19.
Key property values
316 stainless steel yield strength
316: minimum 205 MPa (30 ksi); 316L: 170 MPa (25 ksi); typical annealed 270–310 MPa. Cold-finished bar ≥ 310 MPa; ¼-hard sheet ≥ 515 MPa.
316 tensile strength
316: ≥ 515 MPa (75 ksi); 316L: ≥ 485 MPa (70 ksi); typical 580–620 MPa annealed.
316 hardness
Annealed max 217 HB / 95 HRB (≈ 225 HV); typical 150–190 HB. Not hardenable by heat treatment; cold-worked up to ~40 HRC.
Corrosion resistance
PREN ≈ 23–26 (Mo-dependent). Resists seawater splash, marine atmospheres, sulphuric acid to ~5 % at ambient, phosphoric, acetic and most organic acids, chloride solutions to ~1000 ppm at ambient. Susceptible to chloride SCC above ~60 °C and to crevice corrosion in stagnant warm seawater (use 2205 or 6 % Mo).
High-temperature use
Oxidation limit ≈ 870 °C continuous (925 °C intermittent); ASME creep design above 525 °C requires 316H. Sigma-phase embrittlement on long exposure at 550–900 °C (worse than 304 because of Mo).
Physical properties
Density 8.0 g/cm³, E = 193 GPa, expansion 16 × 10⁻⁶/K (0–100 °C), conductivity 16.2 W/m·K, resistivity 0.74 µΩ·m, non-magnetic (μr ≤ 1.02 annealed).
Heat treatment
Solution anneal 1040–1120 °C (1900–2050 °F), water quench. Avoid 425–860 °C exposure for 316 (sensitization); 316L is immune in practical weld thicknesses.
Weldability
Excellent weldability by all arc, laser and resistance processes without preheat; filler ER316L / E316L-16 (AWS A5.9 / A5.4). Interpass ≤ 150 °C. Use 316L base for welded sections > 6 mm in corrosive service, or solution-anneal 316 after welding. Pickle/passivate welds for chloride exposure. Weld to carbon steel with ER309L.
Machining, forming and heat treatment
Machinability ≈ 40 % of B1112 (slightly gummier than 304); use sharp carbide, positive rake, rigid setups; 316F (free-machining, S31620) exists but is uncommon. Forming, deep drawing and spinning are excellent; slightly higher press loads than 304. Standard finishes per ASTM A480 (2B, BA, No. 4, No. 8); electropolishing widely used for pharma and semiconductor tubing.
Typical applications
- Marine hardware, boat fittings, deck rails, coastal architecture
- Chemical, petrochemical, pulp-and-paper process equipment and piping
- Pharmaceutical, biotech and semiconductor high-purity tubing and vessels (316L, electropolished)
- Food processing in salty or acidic media (brine, pickles, sauces)
- Medical instruments and implants (316LVM / ASTM F138)
- Heat exchangers, condensers and evaporators with brackish cooling water
- Fasteners A4-70/A4-80, ASTM F593 Group 2; springs and wire
- Pool and spa fittings (with maintenance), water treatment, desalination pre-treatment
316 compared with related grades
Frequently asked questions
What is the difference between 316 and 316L?
Carbon: 316 allows up to 0.08 %, 316L only 0.03 %. Low carbon prevents chromium-carbide formation in weld heat-affected zones, so 316L is specified for welded equipment > 6 mm and for corrosive service after welding. 316L's strength minimums are 15–35 MPa lower, but dual-certified 316/316L material meets both.
Is 316 stainless steel magnetic?
No in the annealed state, and even less after cold work than 304 because its higher nickel content stabilizes the austenite. A strong magnetic response indicates a different grade.
Is 316 suitable for seawater?
For marine atmosphere, splash zones and intermittent immersion with cleaning — yes; it is the standard marine grade. For continuous immersion in warm, stagnant seawater it suffers crevice corrosion; use duplex 2205, super-duplex or 6 % Mo austenitics.
What is the European equivalent of 316?
EN 1.4401 (X5CrNiMo17-12-2) for 316 and 1.4404 (X2CrNiMo17-12-2) for 316L. The EN Mo window (2.0–2.5 %) sits inside the ASTM 2.0–3.0 %, so EN material always meets ASTM; 1.4436/1.4432 cover the high-Mo end and 1.4571 is the Ti-stabilized 316Ti.
Why is 316 more expensive than 304?
Molybdenum (2–3 %) and the extra nickel (10–14 % vs 8–10.5 %) are the costliest alloying elements; together they add roughly 20–40 % to the price depending on the Ni/Mo market.
What temperature can 316 withstand?
Continuous service in air to about 870 °C (1600 °F) for oxidation; for pressure parts ASME limits 316 to 425 °C unless it is 316H (carbon ≥ 0.04 %), which is rated to ~815 °C. Avoid long holds at 550–900 °C (sigma phase).
Related grades
Verified against ASTM A240/A240M-22; ASTM A240/A240M-22 Tables 1–2; ASTM A276/A276M-23; ASTM A312/A312M-22; ASME BPVC II-D. Last checked: September 2026.