# UNS S31609 (316H) Forgings to ASTM A182 F316H

**UNS S31609 is type 316 stainless steel with carbon deliberately held between 0.04 and 0.10 percent. The common name is 316H; ASTM A182 calls the forging grade F316H.** The carbon minimum is the reason the grade exists: carbide at the grain boundaries resists creep, so ASME Section II Part D carries allowable stresses for 316H to roughly 816 °C, where 316L stops at 427 °C.

Room-temperature minimums are the same as plain 316, at 515 MPa tensile and 205 MPa yield. The grade earns its price above about 425 °C and nowhere below that.

Forged by Jiangyin Jiangnan Metal Co., Ltd., an integrated melting works and open-die forge in Jiangyin, Jiangsu Province, China.

## Designations

| System | Designation |
|---|---|
| UNS | S31609 |
| Common name | 316H, SS 316H |
| Forgings | ASTM A182 / A182M Grade F316H |
| Plate | ASTM A240 UNS S31609 |
| Pipe | ASTM A312 TP316H |
| Tube | ASTM A213 TP316H |
| Butt-weld fittings | ASTM A403 WP316H |
| Bar | ASTM A479 |
| EN number | 1.4919 |

EN 1.4401 is not the equivalent. That number is X5CrNiMo17-12-2, plain 316, carbon capped at 0.08 percent with no minimum.

## Chemical composition, weight percent

| Element | A182 F316H forgings | A240 plate |
|---|---|---|
| Carbon | 0.04 – 0.10 | 0.04 – 0.10 |
| Chromium | 16.0 – 18.0 | 16.0 – 18.0 |
| Nickel | 10.0 – 14.0 | 10.0 – 14.0 |
| Molybdenum | 2.00 – 3.00 | 2.00 – 3.00 |
| Manganese | 2.00 max | 2.00 max |
| Silicon | 1.00 max | 0.75 max |
| Phosphorus | 0.045 max | 0.045 max |
| Sulphur | 0.030 max | 0.030 max |
| Iron | Balance | Balance |

A heat reporting 0.025 percent carbon is 316 or 316L with an F316H heading on the paperwork, and it will not hold the creep strength the design assumed. Above 0.10 percent, sensitisation risk in the weld heat-affected zone rises instead.

## Mechanical properties, room temperature minimums

| Property | A182 F316H forgings | A240 plate |
|---|---|---|
| Tensile strength, min | 515 MPa (75 ksi) | 515 MPa (75 ksi) |
| Yield strength 0.2 % offset, min | 205 MPa (30 ksi) | 205 MPa (30 ksi) |
| Elongation 50 mm or 4D, min | 30 % | 40 % |
| Reduction of area, min | 50 % | not specified |
| Modulus of elasticity | approx. 193 GPa | approx. 193 GPa |

The elongation difference causes rejected paperwork regularly. Forgings are tested to 30 percent, not the 40 percent figure printed on plate data sheets.

## Creep-rupture strength, 100,000 hours

Indicative published ranges, not specification minimums. They shift with carbon and nitrogen in the individual heat.

| Temperature | 316 / 316L type | 316H | Gain |
|---|---|---|---|
| 500 °C | 95 – 110 MPa | 115 – 130 MPa | approx. 20 % |
| 600 °C | 45 – 55 MPa | 60 – 72 MPa | approx. 30 % |
| 650 °C | 30 – 38 MPa | 40 – 50 MPa | approx. 33 % |

Design against the allowable stress tables in the ASME edition governing your code work.

## Melting, heat treatment, machining, welding

**Melting.** Electric arc furnace, ladle refining, then vacuum oxygen decarburisation where carbon and nitrogen need tight control. That step matters for an H grade, because carbon must land inside a 0.06 percent window rather than simply below a ceiling. Heats to 60 tonnes. Electroslag remelting available when a remelted ingot is specified.

**Solution annealing.** 1040 to 1120 °C, water quenched or force cooled. Slow cooling through 425 to 870 °C precipitates chromium carbide at the grain boundaries and leaves the adjacent metal chromium-poor, so the cooling rate is controlled rather than left to the furnace.

**Machining.** Work-hardens quickly and tears rather than chipping cleanly. Well below martensitic 410 for machinability, roughly level with 304. Rigid setups, positive rake, sharp inserts, heavy constant feed, plenty of coolant; dwelling glazes the cut and destroys the tool.

**Welding.** Match the carbon with ER316H or E316H filler to AWS A5.9 and A5.4. Substituting 316L filler in a creep-loaded joint puts the weakest metal where the stress is. No preheat; keep interpass temperature and heat input low. Post-weld heat treatment is not normally required. The service failure mode is intergranular creep cracking in the heat-affected zone of thick weldments, not pitting.

## Temperature range

| Range | Behaviour |
|---|---|
| to −196 °C | Austenite keeps its toughness; usable but not the design intent |
| ambient – 425 °C | No strength advantage over 316 or 316L; prefer 316L for welded corrosive service |
| 425 – 540 °C | Creep begins to govern; 316L loses its ASME listing at 427 °C |
| 540 – 700 °C | The band the grade exists for; creep controls design |
| 700 – 816 °C | Upper end of pressure-retaining design; oxidation co-limiting |
| above 870 °C | Oxidation-limited; move to 310S, 253 MA or a nickel alloy |

## Grade selection

| Grade | Carbon | Pick it when |
|---|---|---|
| 316L, S31603 | 0.030 max | Under 427 °C and weld corrosion resistance outweighs creep strength |
| 316, S31600 | 0.080 max | General corrosion duty with no sustained creep-range load |
| 316Ti, S31635 | 0.080 max, Ti-stabilised | Static 400 – 900 °C service where intergranular attack dominates; creep strength is lower than 316H, so not a substitute for stressed parts |
| 304H, S30409 | 0.04 – 0.10 | Dry oxidising heat, no chlorides or sulphur; cheaper, no molybdenum |
| 347H, S34709 | 0.04 – 0.10 | Creep service also needing niobium stabilisation |
| **S31609, 316H** | 0.04 – 0.10 | Sustained stress above roughly 425 °C with chlorides, sulphur compounds or process acids present |

316H is not a seawater material. PREN of roughly 24 to 27 beats 304H at 18 to 20, but seawater needs super duplex such as S32750 or S32760, or a 6 percent molybdenum grade.

## Forged product forms and size envelope

| Form | Size envelope | Standards |
|---|---|---|
| Seamless rolled rings | OD 50 – 6,000 mm | A182 F316H, A965 |
| Forged rings, retaining and seat rings | to 30 t single piece | A182 F316H |
| Flanges: weld neck, blind, slip-on, socket weld, lap joint, orifice, long weld neck | to 5,000 mm machined dia | A182 F316H, ASME B16.5, B16.47, MSS SP-44 |
| Round bars, shafts, spindles, eccentric shafts | to 14,000 mm turned length | A182 F316H, A479 |
| Discs, tube sheets, covers, blocks | to 5,000 mm machined dia | A182 F316H |
| Bored cylinders, sleeves, bushings, forged pipe | to 1,600 mm dia × 10,000 mm | A182 F316H |
| Valve and wellhead parts: bodies, bonnets, stems, seat rings, nozzles, manifolds | from 10 kg | A182 F316H, API 6A, NACE MR0175 / ISO 15156 on request |

Minimum order 10 kg with no minimum piece count. Lead time 20 to 60 days.

## Pricing

Quoted per piece against the drawing, not from a price list. The figure depends on finished weight, input billet weight after forging allowance, section thickness, heat-treatment route, machining scope and the required NDT and certification. Nickel and molybdenum surcharges track the alloy market, so any published per-kilogram figure would be out of date within weeks.

## Applications

Fossil power: superheater and reheater components, steam headers, main steam piping. Refining: hydroprocessing reactor internals, reformer and furnace parts, transfer lines, polythionic acid service. Chemical: sulphuric acid plant components, hot process piping. Waste-to-energy: heat recovery surfaces, flue gas ducting. Concentrated solar: molten nitrate salt receivers, hot salt tanks and piping. Oil and gas: hot manifolds, wellhead and Christmas tree components, subsea production hardware. Also nuclear, pulp and paper, pharmaceutical, rubber, plastics and textile plant, as exchangers, condensers, evaporators, columns, towers, silos, preheaters and recuperators.

## Inspection and certification

Ultrasonic testing to EN 10228-3, SEP 1921 or ASTM A388 as the order specifies. Certificates to EN 10204 3.1, or 3.2 with third-party endorsement. On request: positive material identification, grain size to ASTM E112, intergranular corrosion testing to ASTM A262 Practice E, impact testing, hardness survey, dimensional report.

## Manufacturer

| Field | Detail |
|---|---|
| Legal name | Jiangyin Jiangnan Metal Co., Ltd. |
| Business | Integrated melting works, open-die forge and ring rolling mill |
| Established | 1997 |
| Employees | 460, including 9 senior engineers, 32 intermediate engineers and 140 technicians |
| Plant | No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province 214423, China |
| Melting | EF, LF, VOD, VIM, VAR, ESR; 60 t maximum heat |
| Forging | 6,300 t press, 6 m ring mill, 30 t maximum single piece |
| Heat treatment | 14 furnaces, including pit furnaces 15,000 mm deep |
| Approvals | CCS, BV, DNV, LR, NK |
| Telephone | +86 189 2135 9659 |
| Email | sales@steelforgepieces.com |
| Page | https://www.steelforgepieces.com/Stainless-Steel/UNS-S31609.html |

## Sources

ASTM A182/A182M, ASTM A240/A240M, ASME Boiler and Pressure Vessel Code Section II Part D. Creep figures are indicative, not specification minimums; confirm against the certified mill test report and the code edition governing your design.

Reviewed 5 October 2026.