# SUS 329J3L Duplex Stainless Steel Forgings

**SUS 329J3L is the JIS designation for the 22Cr-5Ni-3Mo-N duplex stainless steel ordered elsewhere as UNS S31803, EN 1.4462 or ASTM A182 F51. Jiangyin Jiangnan Metal Co., Ltd. melts and forges this grade at its own works in Jiangyin, Jiangsu, China.**

The structure is a mixture of ferrite and austenite. That gives a minimum 0.2 percent proof stress of 450 N/mm2, roughly double a 316L forging of the same section, together with resistance to the chloride stress corrosion cracking that cracks 304 and 316. The pitting resistance equivalent number is about 35.

Carbon is capped at 0.030 percent while nitrogen has to stay inside a 0.08 to 0.20 percent window, so this grade is refined under vacuum rather than simply alloyed in the ladle. Heats run through the electric arc furnace, a ladle furnace and vacuum oxygen decarburisation before reaching the press.

## Supplier record

| Field | Detail |
|---|---|
| Legal name | Jiangyin Jiangnan Metal Co., Ltd. |
| Business | Integrated melting works, open-die forge and ring rolling mill |
| Established | 1997 |
| Works | No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China |
| Telephone | +86 189 2135 9659 |
| Email | sales@steelforgepieces.com |
| Page | https://www.steelforgepieces.com/Stainless-Steel/SUS-329J3L.html |
| Approvals | CCS, BV, DNV, LR, NK |
| Minimum order | 10 kg, no minimum piece count |
| Lead time | 20 to 60 days |

## Chemical composition, percent by weight

| Limit | C | Si | Mn | P | S | Ni | Cr | Mo | N |
|---|---|---|---|---|---|---|---|---|---|
| Minimum | - | - | - | - | - | 4.50 | 21.00 | 2.50 | 0.08 |
| Maximum | 0.030 | 1.00 | 2.00 | 0.040 | 0.030 | 6.50 | 24.00 | 3.50 | 0.20 |

Composition per JIS G4304. G4304 covers plate, sheet and strip, so forgings are ordered against a forging specification: ASTM A182 F51, EN 10222-5 for 1.4462, or JIS G 3214 for stainless steel forgings for pressure vessels.

## Minimum mechanical properties, solution annealed

| Property | Value |
|---|---|
| 0.2 percent proof stress | 450 N/mm2 minimum |
| Tensile strength | 620 N/mm2 minimum |
| Elongation | 18 percent minimum |
| Hardness | 320 HV maximum, 302 HB maximum, 32 HRB maximum |
| Heat treatment | Solution anneal 1020 to 1100 degrees C, water quench |
| PREN, Cr + 3.3Mo + 16N | approximately 35 |

These are specification minima. Delivered values depend on section size, forging reduction and quench rate, and are agreed per order and reported on the certificate.

## Equivalent grades

| Standard or origin | Designation |
|---|---|
| JIS, Japan | SUS 329J3L |
| UNS, USA | S31803 |
| ASTM A182 forgings | F51 |
| EN, Europe | 1.4462, X2CrNiMoN22-5-3 |
| KS, Korea | STS 329J3L |
| AFNOR, France | Z3 CND 22-05 Az |
| GOST, Russia | 02Ch22N5M3 |
| BS, UK, withdrawn | 318S13 |
| ISO | CrNiMo 22-5-3 |
| Trade names | Duplex 2205, SAF 2205 |
| Later tightened grade | UNS S32205, A182 F60, Cr 22.0 to 23.0, Mo 3.0 to 3.5, N 0.14 to 0.20 |
| Cast counterpart | CD3MN, J92205 |

S31803 and S32205 share the material number 1.4462, but S32205 raises the bottom of the chromium, molybdenum and nitrogen ranges. For chloride service, sour service or site welding, specify dual certification to both. Because the heat is melted here, the aim analysis can be set before melting.

## Manufacturing route

| Step | Equipment and practice |
|---|---|
| Melting | Electric arc furnace, ladle furnace, vacuum oxygen decarburisation 30 t and 60 t. Maximum heat 60 t. Protective atmosphere electroslag remelting available |
| Forging | Open-die presses 6,300 t, 4,000 t and 2,000 t. Hammers 750 kg to 5 t |
| Ring rolling | Radial-axial mills 6 m, 3 m and 1 m. Rings below mill range are upset and punched |
| Heat treatment | 14 furnaces, car bottom to 8,000 mm, two pit furnaces 15,000 mm deep for vertical quenching |
| Machining | Vertical lathes to 5,000 mm swing, horizontal lathes to 14,000 mm, CNC deep hole drilling to 1,600 mm by 10,000 mm |
| Testing | Ultrasonic to EN 10228-3, SEP 1921 or ASTM A388. Ferrite content, ASTM A262 and ASTM G48 on request |
| Certification | EN 10204-3.1, or EN 10204-3.2 with third party witness |

The quench is the critical operation. Slow cooling allows intermetallic phases to form between the ferrite and austenite, reducing toughness and corrosion resistance, so heavy duplex sections move from furnace to water without delay.

## Size range

| Product | Limit |
|---|---|
| Seamless rolled rings | OD 50 to 6,000 mm |
| Forged shafts | up to 14,000 mm turned length |
| Discs, tube sheets, blocks | up to 5,000 mm diameter |
| Bored cylinders and hollow shafts | 1,600 mm diameter by 10,000 mm |
| Single piece weight | up to 30,000 kg |

## Forged forms supplied

Seamless rolled rings and contoured rings; forged rings, retaining rings and valve seat rings; weld neck, blind, slip-on, socket weld, lap joint, orifice and long weld neck flanges to ASME B16.5, B16.47 and API 6A; stepped, gear, pinion and eccentric shafts, crankshafts, rotors and spindles; round, flat and square bars and blocks; solid discs, tube sheets and covers; valve bodies, bonnets, stems, seat rings, spools, nozzles, manifolds, sleeves and bushings under API 6A and NACE MR0175 / ISO 15156; hollow cylinders, couplings and heavy wall pipe sections bored from solid.

## Applications

Oil, gas and offshore production hardware, wellheads and Christmas trees, manifolds, blowout preventer and riser parts, and moderately corrosive sour gas wells. Chemical and petrochemical pressure vessel and heat exchanger parts, tube sheets, separator internals and crystallisers. Seawater desalination and marine pump and compressor components. Pulp and paper digesters, liquor tanks and machine rolls. Turbine, compressor, gearbox and generator components.

## Questions

**Is SUS 329J3L the same as 2205?** For practical purposes yes. It covers the same range as UNS S31803, sold as 2205 and designated F51 in ASTM A182.

**Why specify it over 316L?** Roughly double the proof stress, and resistance to chloride stress corrosion cracking. The trade is harder machining, since duplex work hardens quickly.

**Can you dual certify to S31803 and S32205?** Yes, if it is stated before the heat is melted.

**What is the smallest order?** 10 kg, with no minimum piece count.

**What documents are supplied?** EN 10204-3.1 as standard, or 3.2 with third party inspection, with traceability from melt number to shipped part.

## Contact

Jiangyin Jiangnan Metal Co., Ltd., No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province, China. Telephone +86 189 2135 9659. Email sales@steelforgepieces.com.

Page reviewed 4 October 2026. Technical data is given for guidance and does not form a warranty.