# 1.4057 (X17CrNi16-2 / AISI 431) Open-Die Forgings, Seamless Rolled Rings and Shafts

Source: https://www.steelforgepieces.com/Stainless-Steel/1.4057.html
Published by: Jiangyin Jiangnan Metal Co., Ltd., open-die forging works, Jiangyin, Jiangsu, China
Last reviewed: 22 September 2026

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**1.4057 is a martensitic chromium-nickel stainless steel (15.0 to 17.0 % Cr, 1.50 to 2.50 % Ni, 0.12 to 0.22 % C), listed in EN 10088-3 as X17CrNi16-2 and equivalent to AISI 431 / UNS S43100.** Quenched and tempered it reaches 800 to 950 MPa in the +QT800 condition, or 900 to 1050 MPa in +QT900. Designers specify it when a part has to be stainless and strong at the same time: pump shafts, valve stems, compressor parts, heavy-duty fasteners. Jiangyin Jiangnan Metal Co., Ltd. melts, forges, ring-rolls, heat treats, machines and tests 1.4057 on one site in Jiangyin, Jiangsu, China, and ships it with EN 10204 3.1 certificates.

## 1.4057 at a glance

| | |
|---|---|
| EN material number | 1.4057 |
| EN steel name | X17CrNi16-2 |
| US equivalent | AISI 431 / UNS S43100 |
| Steel type | Martensitic chromium-nickel stainless steel |
| Forging standard | EN 10250-4, composition per EN 10088-3 |
| Delivery conditions | +A, +QT800, +QT900 |
| Tensile strength | 800 to 950 MPa (+QT800), 900 to 1050 MPa (+QT900) |
| Density | 7.7 kg/dm3 |
| Magnetic | Yes, ferromagnetic in all conditions |
| Service range | -40 C to +400 C |
| PREN | about 17.5 to 21.2 |
| Forged by | Jiangyin Jiangnan Metal Co., Ltd., Jiangyin, China |

## What is 1.4057 stainless steel?

1.4057 is a hardenable stainless steel that sits between the plain 13 % chromium martensitic grades and the austenitic stainless steels. Its 15 to 17 % chromium gives genuine stainless behaviour. Its 1.5 to 2.5 % nickel widens the austenite field, so heavy sections harden right through and stay tough. Its 0.12 to 0.22 % carbon lets the steel be quenched and tempered to 800 to 1050 MPa. It is magnetic, it is not an immersion material for seawater, and it must not be tempered in the 400 to 550 C embrittlement range.

The grade gets specified when a shaft, stem or fastener has to resist mildly corrosive media and still carry a real mechanical load. A 1.4301 / 304 austenitic grade would corrode less but cannot be hardened. A 1.4021 / 420 martensitic grade hardens well but has no nickel and less chromium, so it is both less corrosion resistant and less tough once the section gets thick.

For open-die forgings the governing delivery standard is EN 10250-4 (Open die steel forgings for general engineering purposes, Part 4: Stainless steels, current edition 2021). It lists 1.4057 among its grades and takes the composition from EN 10088-3.

## Chemical composition, % by mass

| Standard | C | Si | Mn | P | S | Cr | Ni |
|---|---|---|---|---|---|---|---|
| EN 1.4057 (EN 10088-3:2014) | 0.12-0.22 | max 1.00 | max 1.50 | max 0.040 | max 0.030 | 15.0-17.0 | 1.50-2.50 |
| AISI 431 / UNS S43100 (ASTM A276) | max 0.20 | max 1.00 | max 1.00 | max 0.040 | max 0.030 | 15.0-17.0 | 1.25-2.50 |
| GB/T 14Cr17Ni2 (China) | 0.11-0.17 | max 0.80 | max 0.80 | max 0.035 | max 0.030 | 16.0-18.0 | 1.50-2.50 |

No molybdenum, nitrogen, copper or niobium is specified. Sulphur is sometimes held deliberately at 0.015 to 0.030 % to improve machinability.

## Mechanical properties, EN 10088-3, longitudinal, room temperature

| Condition | Ruling section | Rp0.2 min (MPa) | Rm (MPa) | A min (%) | KV min (J) | Hardness HB |
|---|---|---|---|---|---|---|
| +A (soft annealed) | all | - | max 950 | - | - | max 295 |
| +QT800 | d up to 60 mm | 600 | 800-950 | 14 | 25 | 240-290 |
| +QT800 | 60 to 160 mm | 600 | 800-950 | 12 | 20 | 240-290 |
| +QT900 | d up to 60 mm | 700 | 900-1050 | 12 | 16 | 270-320 |
| +QT900 | 60 to 160 mm | 700 | 900-1050 | 10 | 15 | 270-320 |

**Above 160 mm ruling section, EN 10088-3 stops.** Most open-die forgings are heavier than that. For larger sections the properties, the test-piece location (surface, half radius or centre) and the test direction (longitudinal, tangential or transverse) get agreed between purchaser and manufacturer at the time of order under EN 10250-4. Transverse elongation and impact values come out lower than longitudinal, so specify them explicitly if the design leans on them.

### 0.2 % proof strength at elevated temperature, MPa minimum

| Condition | 100 C | 200 C | 300 C | 400 C |
|---|---|---|---|---|
| +QT800 | 515 | 475 | 440 | 355 |
| +QT900 | 565 | 505 | 470 | 375 |

## Physical properties, EN 10088-1

| Property | Value |
|---|---|
| Density at 20 C | 7.7 kg/dm3 (7 700 kg/m3) |
| Modulus of elasticity | 215 GPa at 20 C, 212 GPa at 100 C, 205 GPa at 200 C, 200 GPa at 300 C, 190 GPa at 400 C |
| Mean coefficient of thermal expansion | 10.0 x 10-6 /K (20 to 100 C); 10.5 x 10-6 /K (20 to 200, 20 to 300 and 20 to 400 C) |
| Thermal conductivity at 20 C | 25 W/(m K) |
| Specific heat capacity at 20 C | 460 J/(kg K) |
| Electrical resistivity at 20 C | 0.70 ohm mm2/m |
| Magnetisable | Yes, in all conditions |
| PREN (Cr + 3.3 Mo + 16 N) | about 17.5 to 21.2 |

## Heat treatment

| Operation | Temperature | Cooling and notes |
|---|---|---|
| Soft annealing (+A) | 680 to 800 C | Furnace or still air, leaves max 295 HB |
| Hardening / austenitising | 950 to 1050 C | Oil, polymer or air quench depending on section |
| Tempering for +QT800 | 750 to 800 C, then a second temper at 650 to 700 C | Water or air. The double temper is what buys the 25 J impact energy |
| Tempering for +QT900 | 600 to 650 C | Water or air. More strength, less toughness |
| Stress relieving | Below the last tempering temperature | Never re-enter 400 to 550 C |

**Avoid 400 to 550 C.** Held in this range the steel suffers 475 C embrittlement. Notched-bar impact energy falls sharply and corrosion resistance drops with it. Producer datasheets advise moving quickly through 420 to 520 C on cooling.

## Forging practice

- Pre-heat slowly to above 850 C. Thermal conductivity is low, and the steel cracks if it is shocked.
- Heat rapidly to 1150 to 1180 C for the forging heat.
- Forge from 1180 C down to 950 C. Do not carry on below roughly 950 C.
- Cool slowly after forging, in the furnace or in an insulating medium. 1.4057 is air hardening.
- Always re-austenitise, quench and temper after forging. +QT800 and +QT900 are produced by a full heat-treatment cycle on the finished forging shape.

## Product forms and size envelope, Jiangyin Jiangnan Metal Co., Ltd.

| Product form | Size range | Typical use in 1.4057 |
|---|---|---|
| Seamless rolled rings | OD 300 to 6 000 mm, wall 40 to 500 mm, height 60 to 1 500 mm | Bearing races, valve seats, compressor casings |
| Forged rings and flanges | OD 100 to 4 000 mm, thickness 30 to 600 mm | Pump and valve flanges |
| Forged shafts and piston rods | dia 80 to 1 200 mm, length up to 8 000 mm | Pump shafts, stems, spindles |
| Discs, blanks and tube sheets | dia 100 to 3 000 mm, thickness 30 to 800 mm | Valve discs, impeller blanks, closures |
| Blocks, plates and rectangles | up to 1 200 x 800 mm section | Die blocks, manifolds, machined bodies |
| Sleeves, bushes and hollow bars | OD 150 to 2 000 mm, ID from 60 mm | Bushings, cylinders, wear sleeves |
| Forged bars, round, square, flat, hex | dia 60 to 1 000 mm | Fastener stock, machined-from-solid parts |

Ring rolling runs on a 6 m mill. Single prototype pieces and repeat production batches are both accepted.

## Equivalent grades

| Standard / country | Designation | Note |
|---|---|---|
| EN 10088-3 / EN 10250-4 (Europe) | 1.4057, X17CrNi16-2 | Reference grade |
| ASTM A276 / A473 (USA) | Type 431, UNS S43100 | A473 is the forging specification |
| AMS (aerospace) | AMS 5628 | Bars, wire and forgings, 431, heat-treatable |
| JIS G4303 (Japan) | SUS 431 | Close equivalent |
| GB/T (China) | 17Cr16Ni2, 14Cr17Ni2 (old 1Cr17Ni2) | 17Cr16Ni2 is the closer match |
| BS 970 (UK) | 431S29 (En57) | Close equivalent |
| AFNOR (France) | Z15CN16-02 | Close equivalent |
| GOST (Russia) | 20Kh17N2 | Close equivalent |
| Old DIN 17440 | X22CrNi17 | Superseded designation |
| SS (Sweden) | 2321 | Close equivalent |

Equivalent does not mean identical. State on the enquiry which standard the certificate must cite.

## Corrosion resistance and grade selection

1.4057 is the most corrosion-resistant of the common hardenable martensitic stainless steels, though it still sits below the austenitic grades. It stands up to water, steam, weak organic acids and atmospheric and marine exposure, and producer datasheets rate its marine-atmosphere resistance as the best of the standard martensitic grades. It is not resistant to reducing acids such as 1 % sulphuric acid, and it will pit in saturated sodium chloride and in stagnant seawater at ambient temperature.

| Grade | Type | Strength | Corrosion resistance | Choose it when |
|---|---|---|---|---|
| 1.4016 / 430 | Ferritic | Low, not hardenable | Moderate | Cosmetic or light-duty parts |
| 1.4021 / 420 | Martensitic 13 % Cr | High | Lower than 1.4057 | Hardness and cost matter more than toughness |
| 1.4057 / 431 | Martensitic Cr-Ni | 800 to 1050 MPa | Good, best of the martensitics | Strength and stainless behaviour in heavy sections |
| 1.4301 / 304 | Austenitic | Low, not hardenable | Better than 1.4057 | Corrosion dominates, load does not |
| 1.4462 / 2205 | Duplex | Higher than 304 | Much better, seawater capable | Chloride service, seawater immersion |
| 1.4542 / 17-4PH | Precipitation hardening | Up to about 1300 MPa | Better than 1.4057 | Highest strength with good corrosion resistance |

## Welding and machining

Welding. 1.4057 welds, but it air hardens, so the cycle has to be controlled. Preheat to roughly 100 to 300 C, hold the interpass temperature above about 200 C, and temper as soon as the weld is finished. A full re-quench and temper is better still. Post-weld tempering around 650 C is common practice on type 431. A matching martensitic filler reaches parent-metal strength; an austenitic filler such as 1.4430 or 1.4370 lets you skip the preheat but will not. Keep hydrogen- and nitrogen-bearing shielding gases away from the joint, and pickle or grind off the heat tint afterwards.

Machining. Machine in the soft-annealed condition (max 295 HB) or after quench and temper. Cutting behaviour is comparable to a structural steel of the same hardness. Indicative speeds with carbide tooling are roughly 80 to 200 m/min turning, 40 to 100 m/min drilling and 140 to 295 m/min milling.

## Typical applications

Pump shafts, impeller blanks, wear sleeves and casings. Valve and wellhead stems, discs, cones, bonnets and seat rings. Compressor impellers, turbine blades and rotor components. Propeller and screw shafts and marine deck machinery. High-strength stainless bolts, studs and nuts. Stirrer shafts, spindles and piston rods in chemical and petrochemical plant. Shafts and tooling in food, soap and vinegar production. Surgical and instrument parts. Normal service range -40 C to +400 C.

## Testing, inspection and certification

- EN 10204 3.1 inspection certificate as standard, EN 10204 3.2 on request
- Inspection by CCS, BV, DNV, LR and NK
- Tensile (Rp0.2, Rm, A, Z), Charpy V-notch impact, Brinell hardness survey
- Ultrasonic examination to EN 10228-3, dye penetrant to EN 10228-2
- Grain size, microstructure, ferrite content, intergranular corrosion testing
- Rough-machined or finish-machined delivery available in-house

## Frequently asked questions

**What is 1.4057 steel?**
1.4057 is a martensitic chromium-nickel stainless steel, listed in EN 10088-3 under the name X17CrNi16-2. It carries 15.0 to 17.0 % chromium, 1.50 to 2.50 % nickel and 0.12 to 0.22 % carbon. The nickel is what separates it from the plain 13 % chromium martensitic grades: it makes the steel tougher and rather more corrosion resistant. Quenching and tempering takes it to 800 to 950 MPa (+QT800) or 900 to 1050 MPa (+QT900).

**Is 1.4057 the same as AISI 431?**
They are treated as equivalents, but the limits are not identical. EN 1.4057 allows carbon 0.12 to 0.22 % and nickel 1.50 to 2.50 %. AISI 431 / UNS S43100 to ASTM A276 allows carbon up to 0.20 % and nickel 1.25 to 2.50 %. Chromium is 15.0 to 17.0 % in both.

**Is 1.4057 magnetic?**
Yes, ferromagnetic in every condition: soft annealed, hardened, quenched and tempered.

**What is the difference between +QT800 and +QT900?**
+QT800 gets a double temper at roughly 750 to 800 C followed by 650 to 700 C, giving Rm 800 to 950 MPa, Rp0.2 at least 600 MPa and KV at least 25 J up to 60 mm diameter. +QT900 is tempered at roughly 600 to 650 C for Rm 900 to 1050 MPa and Rp0.2 at least 700 MPa, but KV drops to 16 J.

**Which standard applies to 1.4057 open-die forgings?**
EN 10250-4. EN 10088-3 supplies the composition and the bar property tables, but its property table for this grade stops at 160 mm. Beyond that, properties and test location are agreed at order. In North America the corresponding forging specification is ASTM A473 for UNS S43100, with AMS 5628 on aerospace work.

**What size 1.4057 forgings can you produce?**
Jiangyin Jiangnan Metal Co., Ltd. rolls seamless rings in 1.4057 up to 6,000 mm outside diameter on its 6 m ring mill, and forges shafts, discs, blocks, sleeves and flanges from the same melt shop. Single prototype pieces and repeat production batches are both accepted.

**Can 1.4057 be welded?**
It can, with control. Preheat 100 to 300 C, interpass above about 200 C, and temper or fully re-quench and temper as soon as the weld is finished.

**Is 1.4057 suitable for seawater?**
It handles marine atmospheres better than any other common martensitic stainless steel, but it is not an immersion material. For continuous immersion use a duplex grade such as 1.4462.

**Which tempering temperatures should be avoided?**
Roughly 400 to 550 C, because of 475 C embrittlement.

**What is the maximum service temperature?**
About 400 C for continuous service.

## Standards cited

- EN 10088-1, Stainless steels, Part 1: List of stainless steels (physical properties)
- EN 10088-3, Stainless steels, Part 3: Technical delivery conditions for semi-finished products, bars, rods, wire, sections and bright products (composition and mechanical properties)
- EN 10250-4:2021, Open die steel forgings for general engineering purposes, Part 4: Stainless steels
- ASTM A473, Standard Specification for Stainless Steel Forgings (UNS S43100)
- ASTM A276, Stainless Steel Bars and Shapes (Type 431)
- AMS 5628, Steel, Corrosion Resistant, Bars, Wire and Forgings, 431, heat treatable
- EN 10204, Metallic products, types of inspection documents
- EN 10228-2 and EN 10228-3, Non-destructive testing of steel forgings

Producer datasheets for 1.4057 / X17CrNi16-2 published by Deutsche Edelstahlwerke (Swiss Steel Group), thyssenkrupp Materials, Dorrenberg Edelstahl, BGH Edelstahl, Rodacciai and Carpenter Technology (Type 431) were cross-checked for the heat-treatment, forging and welding values.

## Contact

Jiangyin Jiangnan Metal Co., Ltd., open-die forging factory
No.1 Chengxiqiao Road, Zhouzhuang Town, Jiangyin City, Jiangsu Province 214423, China
Phone: +86 189 2135 9659
Email: sales@steelforgepieces.com
Web: https://www.steelforgepieces.com/
Hours: Monday to Saturday, 08:00 to 17:30 China Standard Time (UTC+8)

Values on this page are for guidance. The binding values on any order are those on the agreed specification and the EN 10204 certificate.