AISI 316N Forgings (UNS S31651): Composition, Properties and Forged Size Range
Summary
AISI 316N (UNS S31651) is Type 316 stainless steel with nitrogen held between 0.10 and 0.16 per cent. The nitrogen lifts the specified minimum yield strength from 205 MPa to 240 MPa and costs nothing in chloride corrosion resistance, which is why 316N turns up in pressure-containing parts that have to be strong and corrosion resistant at the same time. Jiangyin Jiangnan Metal forges it as bars, hollow bars, seamless rolled rings, discs, shafts and flanges.
- UNS number
- S31651
- Forging spec
- ASTM A182 F316N
- Yield strength, min
- 240 MPa (35 ksi)
- Tensile strength, min
- 550 MPa (80 ksi)
- Nitrogen content
- 0.10 to 0.16 %
- PREN
- 24 to 30 (typically 27)
- Density
- 7.99 g/cm³
- Max piece weight
- 30,000 kg
This page gives the chemical and mechanical specification for AISI 316N, explains how it differs from 316, 316L and 316LN, and lists the forged shapes and sizes we produce in the grade. Unless a figure is marked as typical, every value below is a specified limit taken from the governing ASTM or ASME standard.
What is AISI 316N stainless steel?
AISI 316N is the nitrogen-bearing version of Type 316. Chromium sits at 16 to 18 per cent, nickel at 10 to 14 and molybdenum at 2 to 3, the same as standard 316. The one deliberate difference is 0.10 to 0.16 per cent nitrogen retained in solution.
Nitrogen is an interstitial solid-solution strengthener and it stabilises austenite. In 316N that buys roughly 17 per cent more yield strength than 316 at room temperature, a few points of extra pitting resistance (nitrogen carries a weighting of 16 in the PREN formula), and enough austenite stability that the steel stays effectively non-magnetic after forging and solution annealing.
The carbon ceiling stays at 0.08 per cent, so 316N is not a low-carbon grade. Where a job needs nitrogen strengthening together with low-carbon weldability, the grade to specify is 316LN (UNS S31653).
A note on names. AISI 316N, SS 316N, Type 316N, SUS 316N (JIS), TP 316N (tube), ASTM A182 F316N (forgings) and ASME SA-182 F316N all point at the same alloy, UNS S31651. What changes is the product form and the standard that issued the designation, not the metallurgy.
Chemical composition of AISI 316N
| Element | Symbol | Minimum % | Maximum % |
|---|---|---|---|
| Chromium | Cr | 16.00 | 18.00 |
| Nickel | Ni | 10.00 | 14.00 |
| Molybdenum | Mo | 2.00 | 3.00 |
| Nitrogen | N | 0.10 | 0.16 |
| Manganese | Mn | none | 2.00 |
| Silicon | Si | none | 0.75 |
| Carbon | C | none | 0.08 |
| Phosphorus | P | none | 0.045 |
| Sulfur | S | none | 0.030 |
| Iron | Fe | Balance, roughly 62 to 71 % | |
Iron is the calculated remainder rather than a specified range. Every element is reported on the EN 10204 3.1 certificate supplied with each heat.
Mechanical properties of AISI 316N forgings
The values below are minimum requirements for solution-annealed 316N at room temperature, verified by tensile test on each heat and heat-treatment lot.
| Property | Metric | Imperial | Basis |
|---|---|---|---|
| Tensile strength (UTS), min | 550 MPa | 80 ksi | A182 / A240 |
| Yield strength, 0.2 % offset, min | 240 MPa | 35 ksi | A182 / A240 |
| Elongation in 50 mm, min | 30 % forgings, 35 % plate | same | A182 / A240 |
| Reduction of area, min | 50 % | 50 % | A182 forgings |
| Hardness, max | 217 HBW | 95 HRB | A240 |
| Charpy V impact at −196 °C | 60 J typical | 44 ft·lb | Supplementary test |
Results on annealed forgings normally run well above these minima, commonly 590 to 650 MPa tensile and 270 to 320 MPa yield. Cold-worked material reaches much higher strength but falls outside the annealed specification.
Why the yield figure matters. Standard 316 and 316L are specified at 205 MPa and 170 MPa minimum yield. At 240 MPa, 316N lets a designer take roughly 15 to 20 per cent off the wall thickness of a pressure vessel or valve body at the same allowable stress, without giving up corrosion resistance.
Physical properties of AISI 316N
| Property | Value (metric) | Value (imperial) |
|---|---|---|
| Density | 7.99 g/cm³ | 0.289 lb/in³ (499 lb/ft³) |
| Elastic (Young's) modulus | 193 to 200 GPa | 28 to 29 × 10⁶ psi |
| Poisson's ratio | 0.27 to 0.30 | n/a |
| Melting range | 1,375 to 1,400 °C | 2,505 to 2,550 °F |
| Specific heat capacity, 0 to 100 °C | 500 J/kg·K | 0.12 Btu/lb·°F |
| Thermal conductivity at 100 °C | 16.2 W/m·K | 9.4 Btu/hr·ft·°F |
| Mean thermal expansion, 0 to 100 °C | 16.0 µm/m·K | 8.9 µin/in·°F |
| Thermal diffusivity | about 4.0 mm²/s | n/a |
| Electrical resistivity | 0.74 µΩ·m (74 µΩ·cm) | about 2.3 % IACS |
| Magnetic permeability, annealed | below 1.02 | effectively non-magnetic |
Thermal expansion in austenitic stainless steel runs about half as much again as in carbon steel. Allow for it in machining fixtures and in bolted joints that mix the two materials.
Corrosion resistance and PREN
Pitting Resistance Equivalent Number ranks resistance to chloride pitting from composition alone. For 316N:
Minimum: 16.0 + (3.3 × 2.0) + (16 × 0.10) = 24.2
Maximum: 18.0 + (3.3 × 3.0) + (16 × 0.16) = 30.5
So 316N lands between 24 and 30, with about 27 for a mid-range heat. That is a little ahead of plain 316 at 24 to 26, thanks to the nitrogen term, and well short of duplex 2205 at around 35 or super duplex at 40 and above. 316N does not replace a duplex grade in seawater or in high-chloride sour service.
- Good in: sulfuric, phosphoric and acetic acid service, pulp and paper liquors, moderate chloride process streams, marine atmospheres.
- Use with caution in: hot chloride solutions above roughly 60 °C, where chloride stress corrosion cracking becomes possible.
- Avoid: hydrochloric acid at any concentration, and aerated seawater at elevated temperature.
- Sensitisation: at 0.08 per cent carbon maximum, 316N can sensitise if held between 425 and 860 °C. For welded assemblies with long exposure in that band, specify 316LN.
316 against 316L, 316N and 316LN
| Grade | UNS | Carbon, max | Nitrogen | Yield min | Tensile min | Best suited to |
|---|---|---|---|---|---|---|
| 316 | S31600 | 0.08 % | 0.10 % max | 205 MPa | 515 MPa | General corrosion service, machined parts |
| 316L | S31603 | 0.030 % | 0.10 % max | 170 MPa | 485 MPa | Welded fabrications with no post-weld anneal |
| 316N | S31651 | 0.08 % | 0.10 to 0.16 % | 240 MPa | 550 MPa | Pressure parts needing higher allowable stress |
| 316LN | S31653 | 0.030 % | 0.10 to 0.16 % | 205 MPa | 515 MPa | Welded pressure parts, cryogenic and nuclear |
Rule of thumb: if the part is forged or machined to shape and strength governs the design, 316N is the right call. If it will be welded and cannot be solution annealed afterwards, go to 316LN. Where weldability matters more than strength, 316L does the job. Where neither is critical, plain 316 costs less.
International standards and equivalent grades
| System or country | Designation | Notes |
|---|---|---|
| UNS (USA) | S31651 | Primary identifier |
| AISI / SAE (USA) | 316N, Type 316N | Wrought designation |
| ASTM, forgings | A182 F316N, A965 F316N | Flanges, fittings, valve parts, forged bars |
| ASTM, other forms | A240 316N, A276 316N, A312 TP316N, A479 316N | Plate, bar, pipe, pressure-vessel bar |
| ASME (USA) | SA-182 F316N, SA-240 316N, SA-312 TP316N | Boiler and Pressure Vessel Code Section II |
| JIS (Japan) | SUS 316N | Direct equivalent |
| GB (China) | 06Cr17Ni12Mo2N, 0Cr17Ni12Mo2N | GB/T 1220, GB/T 24511 |
| EN / DIN (Europe) | No exact match. Nearest is 1.4406 (X2CrNiMoN17-11-2) | 1.4406 is low-carbon, closer to 316LN than to 316N |
EN has no carbon-bearing nitrogen-alloyed 316. If a European drawing calls for 1.4406 while the purchase order says 316N, check the carbon requirement with the design authority before ordering. The two are not interchangeable.
Forged AISI 316N products we manufacture
We produce AISI 316N as open-die forgings and seamless rolled rings. We are a forging works rather than a stockist, so every piece is forged from a traceable heat and solution annealed before machining.
| Product form | Size range | Typical use |
|---|---|---|
| Round, square, flat and hex bars | Ø 80 to 1,200 mm, length to 8,000 mm | Machined valve parts, pump shafts, fasteners |
| Hollow bars, sleeves, bushings, cylinders | OD 150 to 2,500 mm, ID from 80 mm, length to 4,000 mm | Pump casings, bearing housings, liners |
| Seamless rolled rings | OD 200 to 4,000 mm, height to 1,500 mm | Flange rings, bearing races, tower sections |
| Open-die forged rings | OD to 3,000 mm, wall from 40 mm | Heavy-wall rings, retaining rings |
| Blocks, discs, plates | Thickness 30 to 800 mm, up to 1,500 × 3,000 mm | Tube sheets, valve bodies, die blocks |
| Shafts and spindles | Ø 100 to 900 mm, length to 6,000 mm | Agitator shafts, pump and turbine shafts |
| Flanges and flange blanks | DN 15 to DN 2000, Class 150 to 2500 | ASME B16.5 and B16.47 piping |
| Single-piece weight | 10 kg to 30,000 kg | n/a |
Non-standard geometry is routine work here. Send a drawing or a sketch with the critical dimensions and we will confirm feasibility and weight.
How we forge and heat treat AISI 316N
- Melting and ingot supply. Steel is melted EAF plus AOD. ESR-remelted ingot is available where cleanliness requirements call for it. Each ingot carries a unique heat number.
- Heating. Ingot is soaked at 1,150 to 1,260 °C. Austenitic stainless is hot-short above 1,260 °C, so furnace uniformity is controlled and recorded.
- Open-die forging. Upsetting and drawing on hydraulic presses at a forging ratio of at least 3:1, and 4:1 or more on critical parts, to break down the cast structure and close porosity. Finish-forging temperature stays above 927 °C.
- Ring rolling. For rings, a pierced and upset preform is rolled to final proportions on a radial-axial ring mill, which gives continuous circumferential grain flow.
- Solution annealing. 1,040 to 1,120 °C, held to section thickness, then rapid water quench. This dissolves carbides, keeps nitrogen in solution and restores full corrosion resistance. A 316N forging that has not been solution annealed does not meet the specification.
- Descaling and machining. Pickling or shot blasting, then rough or finish machining to your drawing.
- Testing and inspection. Chemistry, tensile, hardness, ultrasonic and intergranular corrosion testing as required.
- Marking, documentation and packing. Hard-stamped heat number and grade, EN 10204 3.1 or 3.2 certificate, seaworthy packing.
Machining, welding and fabrication
Machinability
Rate 316N at about 35 to 40 per cent of AISI 1212 free-machining steel, a little tougher than 316 because of the nitrogen. Use rigid setups, positive-rake carbide tooling, heavy positive feed to cut beneath the work-hardened layer, and plenty of coolant. Do not let the tool dwell, since 316N work-hardens quickly.
Welding
316N welds readily by GTAW, GMAW, SMAW and SAW. ER316L or E316L-16 filler suits most joints, with 316LN filler where the nitrogen level has to be matched. No preheat is needed. Keep interpass temperature below 150 °C. A post-weld solution anneal is advisable for corrosive service because of the 0.08 per cent carbon ceiling.
Hot and cold forming
Hot-form between 927 and 1,204 °C, then solution anneal. Cold forming is possible, but the higher yield strength and fast work-hardening rate push forming loads about 20 per cent above 316, so size the press accordingly.
Heat treatment limits
316N cannot be hardened by heat treatment. Strength comes from composition and cold work only, and solution annealing is the single heat treatment applied. Avoid long exposure between 425 and 860 °C in service.
Applications for AISI 316N forgings
- Oil, gas and petrochemical: valve bodies and bonnets, wellhead components, manifold blocks, heat exchanger tube sheets, high-pressure flanges.
- Chemical processing: reactor nozzles, agitator shafts, pump casings and impeller hubs for acidic and chloride-bearing streams.
- Power generation: feedwater and steam valve internals, pressure-retaining forgings for nuclear and conventional plant.
- Marine and offshore: pump shafts, riser components, subsea connector bodies in moderate-chloride service.
- Pulp and paper: digester hardware, bleach plant fittings and rolls.
- Desalination and water treatment: high-pressure pump parts and pipework flanges.
- Pharmaceutical and food: pressure-rated vessel components where 316-level corrosion resistance and higher allowable stress are both specified.
Testing, inspection and certification
| Test | Method or standard | Included as standard |
|---|---|---|
| Chemical analysis | Spectrometer, per heat. PMI on request | Yes |
| Tensile and yield test | ASTM A370, ISO 6892-1 | Yes |
| Hardness | Brinell, ASTM E10 | Yes |
| Dimensional inspection | To customer drawing | Yes |
| Ultrasonic testing | ASTM A388, EN 10228-3 | On request |
| Liquid penetrant testing | ASTM E165 | On request |
| Intergranular corrosion | ASTM A262 Practice E | On request |
| Charpy V-notch impact | ASTM A370, including cryogenic | On request |
| Ferrite content, magnetic permeability | Feritscope | On request |
| Grain size and micrograph | ASTM E112 | On request |
Material certification is issued to EN 10204 type 3.1 as standard, or type 3.2 with third-party witness by SGS, BV, TÜV, Lloyd's Register or your own inspector. Heat traceability is maintained from ingot through to the shipped part.
How to order AISI 316N forgings
For a quotation the same working day, send us five things:
- Grade and specification, such as ASTM A182 F316N or AISI 316N per A965.
- Shape and dimensions. A drawing, or OD by ID by height for rings, or diameter by length for bars. Say whether the dimensions are rough-forged or finish-machined.
- Quantity and required delivery date.
- Testing and certification required: UT class, IGC, impact temperature, 3.1 or 3.2.
- Destination port for freight costing.
Lead time for 316N open-die forgings normally runs 25 to 40 days from order confirmation, depending on size and heat treatment. Minimum order is one piece for large forgings.
Frequently asked questions about AISI 316N
What is the difference between 316 and 316N stainless steel?
316N contains 0.10 to 0.16 per cent nitrogen, which standard 316 does not specify. That nitrogen raises the minimum yield strength from 205 MPa to 240 MPa and the minimum tensile strength from 515 MPa to 550 MPa, and it improves pitting resistance slightly. Chromium, nickel, molybdenum and carbon limits are otherwise identical, so general corrosion behaviour is comparable.
Is AISI 316N the same as ASTM A182 F316N?
Both describe the same alloy, UNS S31651, but A182 F316N is the specific standard for forged flanges, fittings, valves and parts for high-temperature service. If your drawing calls for a forging, order to A182 F316N rather than the bare AISI designation, because A182 adds requirements for forging reduction, heat treatment, testing and marking that the AISI number alone does not cover.
What is the PREN of 316N?
Using PREN = %Cr + 3.3 × %Mo + 16 × %N, AISI 316N gives a PREN between 24.2 and 30.5 depending on where the heat falls within the composition range, with about 27 being typical. That is a few points above plain 316 and well below duplex 2205.
Is 316N magnetic?
No. In the solution-annealed condition 316N is austenitic and effectively non-magnetic, with relative permeability below 1.02. Nitrogen stabilises the austenite, so 316N tends to stay less magnetic than 316 after forging. Heavy cold work can induce a small amount of deformation martensite and a slight magnetic response.
Can 316N be hardened by heat treatment?
No. Like all austenitic stainless steels, 316N cannot be hardened by quenching and tempering. Its strength comes from the alloy composition, chiefly the nitrogen, and from cold work. The only heat treatment applied is solution annealing at 1,040 to 1,120 °C followed by rapid quench, which softens rather than hardens the steel.
What is the maximum service temperature of 316N?
316N resists oxidation in intermittent service to about 870 °C and in continuous service to about 925 °C. Continuous use between 425 and 860 °C is not recommended where corrosion resistance matters, because chromium carbides can precipitate at the grain boundaries. For sustained service in that band, specify the low-carbon 316LN.
Which filler metal should be used to weld 316N?
ER316L or E316L-16 filler is used for most 316N joints. 316LN filler is used where the nitrogen level has to be matched for strength, or where the weld metal must meet the same specification. No preheat is required, interpass temperature is kept below 150 °C, and a post-weld solution anneal is advisable for corrosive service.
What sizes of 316N forgings can be produced?
Jiangyin Jiangnan Metal produces AISI 316N open-die forgings from 10 kg to 30,000 kg per piece: round bars to 1,200 mm diameter, hollow bars and sleeves to 2,500 mm outside diameter, seamless rolled rings to 4,000 mm outside diameter, discs and blocks to 800 mm thick, and shafts to 6,000 mm long.
Where can I buy AISI 316N forgings?
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging works at No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China, producing AISI 316N bars, rings, discs, shafts and flanges to order. Enquiries go to sales@steelforgepieces.com or +86 189 2135 9659. Lead time is normally 25 to 40 days.
Do 316N forgings come with a mill certificate?
Yes. Every shipment carries an EN 10204 type 3.1 certificate recording heat number, full chemical analysis, mechanical test results and heat treatment record. Type 3.2 certification with third-party witness by SGS, BV, TÜV or Lloyd's Register is available on request.
About the manufacturer
Jiangyin Jiangnan Metal Co., Ltd. is an open-die forging works in Jiangyin, Jiangsu Province, China. We forge stainless steel, carbon steel, alloy steel, tool steel and nickel alloys into bars, hollow bars, seamless rolled rings, discs, blocks, shafts and flanges, from 10 kg to 30,000 kg a piece. Everything is made to order against customer drawings and international specifications including ASTM, ASME, EN, DIN, JIS and GB, with EN 10204 3.1 or 3.2 certification and full heat traceability.
Jiangyin lies in the Yangtze River Delta, about 150 km from the Port of Shanghai, which keeps export lead times and freight costs down for buyers in Europe, North America, the Middle East and Southeast Asia.
- Company
- Jiangyin Jiangnan Metal Co., Ltd., open-die forging works
- Address
- No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China
- Telephone
- +86 189 2135 9659, also WhatsApp and WeChat
- sales@steelforgepieces.com
- Website
- www.steelforgepieces.com
- Materials
- Stainless steel, carbon steel, alloy steel, tool steel, nickel alloys
- Capability
- Open-die forging, seamless ring rolling, heat treatment, rough and finish machining
- Serves
- Worldwide export
Jiangyin Jiangnan Metal Co., Ltd. (2026). AISI 316N Forgings (UNS S31651): Composition, Properties and Forged Size Range. steelforgepieces.com. https://www.steelforgepieces.com/Stainless-Steel/AISI-316N.html
Request a quotation for AISI 316N forgings
Send a drawing or your required dimensions and we will come back the same working day with price, weight and lead time. One-piece orders are welcome.
Related stainless steel and nickel alloy grades
If 316N is not quite right for the application, these are the alternatives we forge most often:
Standards referenced
- ASTM A182/A182M, Standard Specification for Forged or Rolled Alloy and Stainless Steel Pipe Flanges, Forged Fittings, and Valves and Parts for High-Temperature Service.
- ASTM A240/A240M and ASME SA-240, Chromium and Chromium-Nickel Stainless Steel Plate, Sheet and Strip for Pressure Vessels. Source of the 550 MPa, 240 MPa and 35 per cent minima for grade 316N, UNS S31651.
- ASTM A965/A965M, Steel Forgings, Austenitic, for Pressure and High-Temperature Parts.
- ASTM A276, A312 and A479, bar, seamless pipe and pressure-vessel bar forms of Type 316N.
- ASTM A370, Test Methods and Definitions for Mechanical Testing of Steel Products.
- ASTM A388, Ultrasonic Examination of Steel Forgings.
- ASTM A262, Detecting Susceptibility to Intergranular Attack in Austenitic Stainless Steels.
- EN 10204, Metallic products: types of inspection documents.
- JIS G 4303 (SUS 316N) and GB/T 1220 (06Cr17Ni12Mo2N), Japanese and Chinese equivalents.
Check requirements against the current edition of the governing standard and against your project specification. The figures here are for engineering guidance and do not replace a purchase specification or a mill certificate.