On this page 13 sections
What is SS 316L Stainless Steel?
Quick answer
- Definition
- SS 316L is the low-carbon (0.030% max) version of SS 316 molybdenum-bearing austenitic stainless steel, preferred for welded equipment exposed to chlorides and mild acids.
- Family
- Austenitic stainless steel
- Key strength
- Carbon 0.030% max for weld-zone corrosion resistance
- Main forms
- Pipes, Tubes, Plates, Sheets, Coils, Bars
- Typical uses
- Chemical and fertiliser process piping; Pharmaceutical and biotech process equipment; Food, dairy and beverage equipment
Grade 316L belongs to the 18-8 austenitic family, with molybdenum added. Nickel (10–14%) stabilises the austenite, which keeps the steel non-magnetic in the annealed condition and tough down to cryogenic temperatures. Chromium forms the passive film, and 2–3% molybdenum strengthens it against chlorides.
The "L" matters when parts are welded and can't be solution-annealed afterwards. With carbon at 0.030% maximum, very little chromium is tied up as carbides at grain boundaries during welding, so the heat-affected zone keeps its resistance to intergranular corrosion. Mills commonly supply dual-certified SS 316/316L, which meets the carbon limit of SS 316L and the strength of SS 316.
Key characteristics
- Carbon 0.030% max for weld-zone corrosion resistance
- 2–3% molybdenum for chloride pitting resistance
- Commonly dual-certified SS 316/316L
- Default choice for welded pharma, chemical and marine equipment
What are the specifications and equivalents of SS 316L?
| Product form | Specification / designation | Product page |
|---|---|---|
| Pipes | ASTM A312 / ASME SA312 TP316L (seamless & welded); A358 EFW | SS 316L pipes → |
| Tubes | ASTM A213 TP316L (seamless); A249 / A269 TP316L (welded) | SS 316L tubes → |
| Plates | ASTM A240 / ASME SA240 316L | SS 316L plates → |
| Sheets | ASTM A240 / ASME SA240 316L | SS 316L sheets → |
| Coils | ASTM A240 / ASME SA240 316L | SS 316L coils → |
| Bars | ASTM A276 / A479 316L | SS 316L bars → |
| Fittings | ASTM A403 WP316L (butt-weld); A182 F316L (forged) | SS 316L fittings → |
| Flanges | ASTM A182 / ASME SA182 F316L | SS 316L flanges → |
| Angles | ASTM A276 / A484 316L | SS 316L angles → |
| Channels | ASTM A276 / A484 316L | SS 316L channels → |
| Bolts | ASTM A193 B8M / SS 316L bolting | SS 316L bolts → |
| Nuts | ASTM A194 Grade 8ML / 8M | SS 316L nuts → |
| Washers | SS 316L flat washers | SS 316L washers → |
UNS S31603 · EN 1.4404 (cross-reference; limits are similar but not identical)
Standards: ASTM A312, ASTM A358, ASTM A213, ASTM A249, ASTM A269, ASTM A270, ASTM A240, ASTM A276, ASTM A182, ASTM A403, NACE MR0175, ASTM A262, ASTM A479, ASTM A480, ASTM A554, EN 10088, EN 10216, EN 10217, ASME B31.3.
What is the chemical composition of SS 316L?
| Element | Limit (%) |
|---|---|
| C | 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 |
What are the mechanical properties of SS 316L?
| Property | Value |
|---|---|
| Tensile strength | 485 MPa (70 ksi) |
| Yield strength (0.2% offset) | 170 MPa (25 ksi) |
| Elongation | 40% |
| Hardness | 217 HBW / 95 HRB |
Physical properties and service temperature
| Property | Value |
|---|---|
| Density (typical) | 8 g/cm³ (8000 kg/m³) |
| Magnetism | Essentially non-magnetic when annealed; cold work can make it slightly magnetic. |
| Heat treatment | Solution annealed and rapidly cooled. It can't be hardened by heat treatment, only by cold work. |
| Service temperature | Good toughness down to cryogenic temperatures; oxidation resistance depends on chromium content. |
| PREN (Cr + 3.3Mo + 16N) | 23 – 25. See the PREN calculator |
How is SS 316L welded and fabricated?
Excellent weldability by TIG, MIG, SMAW and SAW with matching filler. Post-weld heat treatment is not normally needed.
Always follow a qualified welding procedure (for example ASME Section IX) and the filler-metal recommendations for SS 316L. Verify incoming material by PMI and check the mill test certificate against the specification.
Which SS 316L products do we supply?
SS 316L Stainless Steel is available in 13 product forms, from ready stock or mill-sourced to your specification, with EN 10204 3.1 mill test certificates (3.2 with third-party inspection on request).
SS 316L CoilsASTM A240 316LSpecification & sizes
How it's madeHot-rolled coil (HRC) comes from the hot-strip mill. Cold-rolled coil (CRC) is further reduced on a cold mill, then annealed and pickled or bright annealed, and skin-passed. Slitting lines cut master coils into narrow strips to the width you order.
- Specification
- ASTM A240 / ASME SA240 316L
- Size range
- Thickness about 0.3 – 12 mm; widths from narrow slit strip (about 10 mm) to 1,250 / 1,500 / 2,000 mm; coil ID 508 / 610 mm; coil weights to order
- Finish
- No.1 (hot-rolled, annealed, pickled), 2B, 2D, BA, No.4 for stainless; HR black, pickled & oiled, CR for carbon steel
- Ends
- Mill edge or slit edge
Testing & documents
- Chemical and mechanical tests
- Thickness profile and surface inspection
- Hardness and bend tests
- EN 10204 3.1 certificate; 3.2 with third-party inspection
SS 316L AnglesASTM A276 / A484 316LSpecification & sizes
How it's madeHot-rolled from billets on section mills (carbon steel), hot-rolled or laser-fused (stainless steel), or extruded (aluminium).
- Specification
- ASTM A276 / A484 316L
- Size range
- Equal angles about 20 × 20 × 3 mm to 200 × 200 × 25 mm; unequal angles to order; lengths 6 m / 12 m or cut
- Finish
- Mill black, shot-blasted and primed, galvanised; pickled or polished (stainless)
- Ends
- Saw-cut to length; drilled or punched on request
Testing & documents
- Chemical and mechanical tests
- Dimensional and straightness checks
- EN 10204 3.1 certificate; 3.2 with third-party inspection
SS 316L ChannelsASTM A276 / A484 316LSpecification & sizes
How it's madeHot-rolled on section mills (carbon steel), hot-rolled or laser-fused (stainless), or extruded (aluminium).
- Specification
- ASTM A276 / A484 316L
- Size range
- ISMC 75 – ISMC 400 and equivalents; UPN 80 – UPN 400; lengths 6 m / 12 m or cut
- Finish
- Mill black, primed or galvanised; pickled or polished (stainless)
- Ends
- Saw-cut to length
Testing & documents
- Chemical and mechanical tests
- Dimensional and straightness checks
- EN 10204 3.1 certificate; 3.2 with third-party inspection
SS 316L BoltsASTM A193 B8M / SS 316L boltingSpecification & sizes
How it's madeCut from heat-treated bar (or forged and heat treated), then threaded by rolling or cutting, and coated if required.
- Specification
- ASTM A193 B8M / SS 316L bolting
- Size range
- M6 – M100 and ¼" – 4" (larger on request); lengths to flange tables or drawing
- Finish
- Plain, black oxide, zinc, hot-dip galvanised, PTFE-based fluoropolymer, zinc-nickel
- Ends
- Chamfered points; full or partial thread
Testing & documents
- Chemical and mechanical tests of bar and finished bolts
- Hardness tests
- Proof-load and wedge tests where applicable
- Coating thickness and adhesion
- EN 10204 3.1 certificate; 3.2 with third-party inspection
SS 316L NutsASTM A194 Grade 8ML / 8MSpecification & sizes
How it's madeHot-forged or cold-formed from bar, heat treated (for hardenable grades), tapped and coated if required.
- Specification
- ASTM A194 Grade 8ML / 8M
- Size range
- M6 – M100 and ¼" – 4"; heavy hex to ASME B18.2.2; metric to ISO 4032 / 4033
- Finish
- Plain, zinc, galvanised (tapped oversize), fluoropolymer
Testing & documents
- Proof-load tests
- Hardness tests
- Chemical analysis
- EN 10204 3.1 certificate; 3.2 with third-party inspection
SS 316L WashersSS 316L flat washersSpecification & sizes
How it's madeStamped or machined from plate or strip and heat treated where required.
- Specification
- SS 316L flat washers
- Size range
- M6 – M100 and ¼" – 4" bolt sizes
- Finish
- Plain, zinc, galvanised
Testing & documents
- Hardness tests
- Dimensional checks
- EN 10204 3.1 certificate; 3.2 with third-party inspection
Where is SS 316L used?
Typical applications
- Chemical and fertiliser process piping
- Pharmaceutical and biotech process equipment
- Food, dairy and beverage equipment
- Heat exchangers and condensers
- Marine hardware above the waterline
- Instrumentation and hydraulic tubing
Where do we supply SS 316L?
SS 316L is regularly requested for projects in these markets:
What should you specify when buying SS 316L?
- Grade and specification, e.g. ASTM A312 TP316L
- Product form, size and tolerance
- Heat treatment / condition and surface finish
- Quantity, delivery location and required date
- Tests: PMI, hydro/NDT, IGC, impact or hardness as required
- Certificate type (EN 10204 3.1 / 3.2) and third-party inspection
See our RFQ checklist guide and what drives metal prices.
Explore more on SS 316L
SS 316L products
Guides
Comparisons & articles
Related grades
Frequently asked questions
What is the difference between SS 316 and SS 316L?
Carbon content: SS 316L has 0.030% maximum against 0.08% for SS 316, which reduces sensitisation during welding. SS 316 has slightly higher minimum strength.
Can SS 316L be used in seawater?
SS 316L performs well in marine atmospheres, but it's prone to crevice and pitting corrosion in warm or stagnant seawater. Super duplex, 6Mo (254 SMO), titanium or cupro-nickel are usual for immersion service.
How can I verify SS 316L on receipt?
Handheld XRF confirms Cr, Ni and Mo, but it can't measure carbon. Use OES or a laboratory analysis, and check the carbon value on the mill certificate.
What is SS 316L used for?
Chemical and fertiliser process piping, Pharmaceutical and biotech process equipment, Food, dairy and beverage equipment, Heat exchangers and condensers. It's used across Chemical Processing, Pharmaceutical & Biotech, Food & Beverage Processing, Marine & Offshore.
What is the UNS number of SS 316L?
SS 316L is designated UNS S31603; the closest EN cross-reference is 1.4404.
Which product forms is SS 316L available in?
Pipes, Tubes, Plates, Sheets, Coils, Bars, Fittings, Flanges, Angles, Channels, Bolts, Nuts, Washers, to ASTM A312 TP316L, ASTM A213 TP316L, ASTM A240 316L and related specifications.
What is the density of SS 316L?
About 8 g/cm³ (8000 kg/m³), used for weight calculations.
Is SS 316L magnetic?
Essentially non-magnetic when annealed; cold work can make it slightly magnetic.
What is the PREN of SS 316L?
Typically 23 – 25, using PREN = Cr + 3.3Mo + 16N. PREN ranks pitting resistance but isn't a design guarantee.
What temperature can SS 316L withstand?
Good toughness down to cryogenic temperatures; oxidation resistance depends on chromium content.