316L stainless steel properties
An austenitic 17Cr-12Ni-2Mo stainless with the carbon held below 0.030 %. The molybdenum resists chloride pitting, and the low carbon keeps a welded joint from sensitising.
- TypeAustenitic Cr-Ni-Mo stainless, not hardenable by heat treatment
- StandardsJIS G4303 SUS316L · ASTM A276 / A479 UNS S31603 · EN 1.4404 · GB 022Cr17Ni12Mo2
- Density8.0 g/cm³
- Tensile485 MPa minimum annealed to ASTM A276
- Yield170 MPa minimum annealed. Lower than 316, and that's the price of the L
- Hardness217 HB maximum annealed. Work hardens as it's cut, like all austenitics
- Molybdenum2.00–3.00 %, which gives it the pitting resistance 304 lacks
- The LCarbon 0.030 % maximum, so welded joints resist carbide precipitation without post-weld annealing
- ServiceSeawater and coastal air, chemical and pharmaceutical contact, food processing, surgical instruments
- CertificateMill test certificate to EN 10204 3.1 on request
316 and 316L should not be swapped on a drawing. 316L has lower carbon and so lower strength. 316 is stronger but sensitises when welded. If the print says one and the market only has the other, we tell you what is available and wait for your written approval before we buy.
316L grade equivalents
| Grade | JIS (Japan) | US (ASTM / AISI / UNS) | GB/T (China) | EN / DIN (Europe) | Cross-reference |
|---|---|---|---|---|---|
| SUS 316L the welded default | SUS316L (JIS G4303) | 316L · UNS S31603 · ASTM A276 / A479 | 022Cr17Ni12Mo2 | X2CrNiMo17-12-2 · EN 1.4404 | Standard equivalent |
| SUS 316 higher carbon, higher strength | SUS316 | 316 · UNS S31600 | 06Cr17Ni12Mo2 | X5CrNiMo17-12-2 · EN 1.4401 | Standard equivalent |
| SUS 316Ti titanium stabilised | SUS316Ti | 316Ti · UNS S31635 | 06Cr17Ni12Mo2Ti | X6CrNiMoTi17-12-2 · EN 1.4571 | Standard equivalent |
| SUS 304 no molybdenum | SUS304 | 304 · UNS S30400 | 06Cr19Ni10 | X5CrNi18-10 · EN 1.4301 | Standard equivalent |
Designations taken from JIS G4303, ASTM A276 and A479, GB/T 20878 and EN 10088-3. In Europe both EN 1.4404 and EN 1.4435 are sold as 316L. 1.4435 carries more molybdenum and nickel, and it's usually what pharmaceutical drawings mean. If your print gives the EN number instead of 316L, we buy to the EN number. Last reviewed 13 September 2026.
When the molybdenum earns its cost
Use it in chlorides
Coastal and offshore installations, seawater and brine, swimming pool hardware, de-icing salt, chlorinated cleaning chemicals. In these conditions 304 develops pinhole pits that no polishing removes.
Use it for surgical and laboratory instruments
Non-implant surgical instruments, dental and laboratory tooling that's autoclaved and chemically cleaned over and over. If your drawing calls for an implantable grade to ASTM F138, say so clearly. That's a different specification with its own certification chain.
Use it where the part is welded and stays wet
The low carbon matters most when a welded joint sits in a corrosive environment. A 316 weld that has sensitised will corrode along the heat-affected zone even though the parent metal is fine.
Generally unnecessary for indoor, chloride-free service
On a bracket in a dry factory you would be paying for corrosion resistance the part never uses. 304 is cheaper, faster to cut and easier to source in Vietnam.
It will not get you hardness
Like 304, 316L cannot be hardened by heat treatment. A drawing that specifies 316L together with a hardness in HRC contradicts itself. A part that needs hardness belongs in 17-4PH.
It costs more to cut as well as to buy
316L is gummier than 304. Chips hang on longer, tools wear faster and we run lower feeds. Expect the machining line on the quotation to go up along with the material line.
Machining process
316L behaves like 304, only harder to live with. The rule is the same (the tool must never stop cutting), and when you break it the damage shows up sooner.
- TurningMori Seiki and Okuma lathes to Ø 310 × 800 mm, including twin-spindle, at ±0.005 mm typical
- MillingDoosan, Haas, Hision and FANUC RoboDrill machining centres, 3, 4 and 5-axis
- Chip controlChip breaking is the first thing we set up. A long stringy 316L chip wraps round the part and ruins the finished surface
- ToolingSharp positive-rake carbide with a stainless coating. Edges are changed on a schedule, before they fail
- Feed ruleConstant feed, no dwell, no light spring passes over a hardened skin
- CoolantFlood coolant at proper concentration and pressure, through-spindle where the tool allows
- Deep borePeck and clear the chips. Leave heat and chips trapped in a deep 316L bore and you lose the drill
- InspectionMitutoyo CRYSTA-APEX V CMM in a climate-controlled lab, reported in inch and millimetre
These are routine figures, not a blanket specification. General tolerance follows ISO 2768 fine or medium class as your print calls it. For long, slender turned parts and deep bores, send the drawing first so the tolerance can be confirmed before the PO.
Compatible finishing processes
- PassivationPassivation to the ASTM A967 class your drawing names, checked before shipping
- ElectropolishElectropolishing. Hygienic and instrument parts normally call for it
- PolishingMechanical polishing to a specified Ra where the drawing calls for a surface value
- BlastingGlass or ceramic bead blast, on media never used on carbon steel
- MarkingLaser marking for part number, revision and lot. On corrosion-critical parts we use it in place of stamping
- Not forAnodising or zinc plating. Both defeat the reason 316L was specified
Put a number on the surface. "Polished" and "mirror" mean something different in every shop. Write an Ra value on the drawing and, where it matters, an ASTM A967 passivation class, so both can be measured at inspection. Full finishing list →
Stock and lead time
- BarRound and flat bar in 316L available from Vietnamese stockists in common sizes
- PlateCommon thicknesses available; thick and oversized plate confirmed per job
- EN 1.4435Ordered in where a pharmaceutical drawing names it rather than generic 316L
- QuoteWithin 24 business hours of a complete RFQ
- Lead timePrototype 3–7 days · small batch 7–14 days · standard 14 days after PO
- CertificateEN 10204 3.1 mill certificate on request, with a dimensional report in inch and millimetre
We confirm actual stock and section size at quotation rather than promising a figure here. If a drawing names a specific EN number or a compliance standard beyond the grade, send it with the RFQ. Buying to that's a different purchase from generic 316L.
Common questions
What is the real difference between 304 and 316L?
Two to three percent molybdenum. That gives 316L much better resistance to chloride pitting from seawater, coastal air, pool chemicals and de-icing salt. In dry indoor service you get nothing extra for the money.
What does the L in 316L mean?
Carbon held to 0.030 % maximum. It stops chromium carbide forming at the grain boundaries when the part is welded, which is what causes corrosion along a weld line. The cost is slightly lower strength than plain 316.
Is SUS316L the same as EN 1.4404?
Yes, they cross-reference cleanly. Europe also sells EN 1.4435 as 316L, though. It carries more molybdenum and nickel and is usually what pharmaceutical drawings mean. If your print names the EN number, we buy to the number.
Can you machine implant-grade 316L?
Implant grades to ASTM F138 are a separate specification with their own certification chain. Tell us at RFQ stage if the part needs that. Our routine 316L work is non-implant surgical, dental and laboratory instruments.
Can 316L be hardened to a HRC value?
No. It cannot be hardened by heat treatment, only by cold work. A drawing that calls for 316L at a given HRC needs sorting out before the PO, and the part probably belongs in 17-4PH.
Do you electropolish?
Yes. Put the required Ra and the passivation class on the drawing so the result can be measured.
Why is 316L quoted higher than 304 by more than the material price difference?
Because it also cuts slower. The chips are gummier, tools do not last as long and feeds come down, so machining hours go up on top of the bar cost.
Related information
304 stainless steel
The default austenitic grade. Cheaper, faster to cut, and good enough for anything that stays out of chlorides.
17-4PH stainless steel
Corrosion resistance plus real hardness, where H900 and H1075 are different materials in practice.
Finishing and heat treatment
Passivation, electropolishing and the heat treatment conditions we specify and verify before shipping.