Martensitic stainless steel, EN 10250-4 open-die forgings
1.4057 (X17CrNi16-2 / AISI 431) Open-Die Forgings, Seamless Rolled Rings and Shafts
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.
Request a 1.4057 quotation See our forging envelope
1.4057 at a glance
- EN material number
- 1.4057
- EN steel name
- X17CrNi16-2
- US equivalent
- AISI 431 / UNS S43100
- Steel type
- Martensitic Cr-Ni stainless
- Forging standard
- EN 10250-4, composition per EN 10088-3
- Delivery conditions
- +A, +QT800, +QT900
- Tensile strength
- 800 to 950 MPa / 900 to 1050 MPa
- 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. 1.4057 is the compromise most pump, valve and compressor builders have settled on.
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 of 1.4057
| Element | C | Si | Mn | P | S | Cr | Ni |
|---|---|---|---|---|---|---|---|
| EN 1.4057 | 0.12–0.22 | ≤ 1.00 | ≤ 1.50 | ≤ 0.040 | ≤ 0.030 | 15.0–17.0 | 1.50–2.50 |
| AISI 431 / UNS S43100 (ASTM A276) | ≤ 0.20 | ≤ 1.00 | ≤ 1.00 | ≤ 0.040 | ≤ 0.030 | 15.0–17.0 | 1.25–2.50 |
| GB/T 14Cr17Ni2 (China) | 0.11–0.17 | ≤ 0.80 | ≤ 0.80 | ≤ 0.035 | ≤ 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, so say on the enquiry if your part is machined from solid. We melt 1.4057 in our own melt shop, which means the heat analysis can be aimed at the narrower overlap of EN 1.4057 and AISI 431 when a dual-certified forging is needed.
Mechanical properties of 1.4057
Room-temperature properties in the quenched and tempered conditions, longitudinal test direction, per EN 10088-3:
| Condition | Ruling section | Rp0.2 min, MPa | Rm, MPa | A min, % | KV min, J | Hardness HB |
|---|---|---|---|---|---|---|
| +A (soft annealed) | all | – | ≤ 950 | – | – | ≤ 295 |
| +QT800 | d ≤ 60 mm | 600 | 800–950 | 14 | 25 | 240–290 |
| +QT800 | 60 < d ≤ 160 mm | 600 | 800–950 | 12 | 20 | 240–290 |
| +QT900 | d ≤ 60 mm | 700 | 900–1050 | 12 | 16 | 270–320 |
| +QT900 | 60 < d ≤ 160 mm | 700 | 900–1050 | 10 | 15 | 270–320 |
The EN 10088-3 property table for 1.4057 runs only to 160 mm, and 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. Settle it before the order goes in, not after the forging has been cut up. 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
| Condition | 100 °C | 200 °C | 300 °C | 400 °C |
|---|---|---|---|---|
| +QT800 | 515 | 475 | 440 | 355 |
| +QT900 | 565 | 505 | 470 | 375 |
Continuous service above roughly 400 °C is not recommended. At that point the service temperature is closing on the tempering temperature of the part, and the strength won by quenching and tempering starts to be given back.
Physical properties of 1.4057
| 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 × 10⁻⁶ K⁻¹ (20 to 100 °C); 10.5 × 10⁻⁶ K⁻¹ (20 to 200, 20 to 300 and 20 to 400 °C) |
| Thermal conductivity at 20 °C | 25 W·m⁻¹·K⁻¹ |
| Specific heat capacity at 20 °C | 460 J·kg⁻¹·K⁻¹ |
| Electrical resistivity at 20 °C | 0.70 Ω·mm²/m (0.70 µΩ·m) |
| Magnetisable | Yes, in the annealed and in the quenched and tempered condition |
| PREN (Cr + 3.3 Mo + 16 N) | about 17.5 to 21.2 |
Heat treatment of 1.4057
| Operation | Temperature | Cooling and notes |
|---|---|---|
| Soft annealing (+A) | 680 to 800 °C | Furnace or still air. Leaves ≤ 295 HB for machining. |
| Hardening / austenitising | 950 to 1050 °C | Oil, polymer or air quench depending on section. Thin sections harden in air. |
| 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 than +QT800. |
| Stress relieving after machining | Below the last tempering temperature | Never re-enter the 400 to 550 °C embrittlement band. |
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. Neither +QT800 nor +QT900 tempering enters this band, which is no accident.
Forging 1.4057, practice and our size envelope
Forging temperatures
- Pre-heat slowly to above 850 °C. Thermal conductivity is low at 25 W·m⁻¹·K⁻¹, 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. The steel work-hardens fast and forging cracks follow.
- Cool slowly after forging, in the furnace or in an insulating medium. 1.4057 is air hardening, so an uncontrolled cool leaves hard, crack-prone martensite.
- Always re-austenitise, quench and temper after forging. Forged-and-cooled properties are not the delivery condition. +QT800 and +QT900 are produced by a full heat-treatment cycle on the finished forging shape.
1.4057 product forms and size envelope
| 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, blind and weld-neck forms |
| Forged shafts and piston rods | Ø 80 to 1 200 mm, length up to 8 000 mm | Pump shafts, stems, spindles, piston rods |
| Discs, blanks and tube sheets | Ø 100 to 3 000 mm, thickness 30 to 800 mm | Valve discs, impeller blanks, closures |
| Blocks, plates and rectangles | Up to 1 200 × 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 | Ø 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, because melting, forging, heat treatment, machining and testing all sit on the same site. Send a drawing, or just the finished size and weight, to sales@steelforgepieces.com and you get a machining-allowance proposal with the quotation.
1.4057 equivalent grades and specifications
| Standard / country | Designation | Note |
|---|---|---|
| EN 10088-3 / EN 10250-4 (Europe) | 1.4057, X17CrNi16-2 | The reference grade on this page |
| ASTM A276 / A473 (USA) | Type 431, UNS S43100 | A473 is the forging spec. C ≤ 0.20 %, Ni 1.25 to 2.50 % |
| 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. 14Cr17Ni2 runs Cr 16 to 18 % |
| 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. Composition and property limits differ between standards, so state on the enquiry which standard the certificate must cite. Dual certification to EN 1.4057 and ASTM A473 S43100 is routine here once the heat analysis is aimed at the overlap.
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 only |
| 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 |
We forge 17-4PH, PH13-8Mo and 17-7PH as well. If 1.4057 turns out to be the wrong side of the line for your service conditions, the alternative comes from the same works.
Welding and machining 1.4057
Welding
1.4057 welds, but it air hardens, so the heat-affected zone will transform to martensite unless the cycle is controlled.
- Preheat to roughly 100 to 300 °C, below the martensite start temperature.
- Hold the interpass temperature above about 200 °C throughout. Do not let the joint go cold between passes.
- Temper immediately after welding. Better still, re-austenitise, quench and temper the whole part. Post-weld tempering around 650 °C is common practice on type 431.
- Pick the filler for the job. A matching martensitic filler reaches full joint strength. An austenitic filler such as 1.4430 or 1.4370 lets you skip the preheat but will not match the parent metal.
- Keep hydrogen- and nitrogen-bearing shielding gases off the joint, and remove heat tint by pickling or grinding so the passive film can re-form.
Machining
Machine in the soft-annealed condition (+A, ≤ 295 HB) or after quench and temper. Producer datasheets describe the cutting behaviour as 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. Soft annealed, the steel is prone to built-up edge, so keep feeds positive and tools sharp. Where a part is largely machined from solid, ask for the controlled-sulphur variant at enquiry stage.
Typical applications of 1.4057 forgings
- Pumps. Pump shafts, impeller blanks, wear sleeves, casings.
- Valves and wellheads. Stems, discs, cones, bonnets, seat rings.
- Compressors and turbines. Impellers, blades, rotor components.
- Marine. Propeller and screw shafts, deck machinery, fittings exposed to marine air.
- Fasteners. High-strength stainless bolts, studs and nuts.
- Process plant. Stirrer shafts, spindles, piston rods, chemical and petrochemical hardware.
- Food, soap and vinegar production. Shafts and tooling in mildly corrosive media.
- Surgical and instrument work. Parts needing hardness together with stainless behaviour.
Normal service range is −40 °C to +400 °C.
Testing, inspection and certification
- EN 10204 3.1 inspection certificate as standard. Heat analysis, heat-treatment record and mechanical test results, traceable to the heat number. EN 10204 3.2 countersigned by a third party on request.
- Class society inspection. The works is used to surveys by CCS, BV, DNV, LR and NK.
- Mechanical testing. Tensile (Rp0.2, Rm, A, Z), Charpy V-notch impact at ambient or low temperature, Brinell hardness survey.
- Non-destructive testing. Ultrasonic examination to EN 10228-3 for martensitic steel forgings, dye penetrant to EN 10228-2, magnetic particle where the structure allows.
- Metallurgical testing. Grain size, microstructure, ferrite content, intergranular corrosion testing.
- Dimensional. Machining allowance agreed before forging. Rough-machined or finish-machined delivery available in-house.
Because EN 10088-3 stops at 160 mm, the certificate on a heavy 1.4057 forging only means something if the test-piece location and direction were agreed in writing beforehand. We put that on the order acknowledgement.
How to order 1.4057 open-die forgings
Send these six items to sales@steelforgepieces.com and a quotation normally follows within one working day.
- Drawing or finished dimensions, plus whether you want as-forged, rough-machined or finish-machined.
- Standard to certify to. EN 10250-4 / EN 10088-3, ASTM A473 S43100, AMS 5628, or a customer specification.
- Delivery condition. +A, +QT800 or +QT900.
- Test requirements. Test-piece location and direction, impact test temperature, UT class, any NDT.
- Certificate type. EN 10204 3.1 or 3.2, and any third-party inspection.
- Quantity and required delivery date.
Frequently asked questions about 1.4057
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). Pump shafts, valve stems, fasteners and compressor components are the usual jobs.
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. One heat can normally be made to satisfy both specifications, and Jiangyin Jiangnan Metal Co., Ltd. aims the analysis at that overlap whenever a dual certificate is asked for.
Is 1.4057 magnetic?
Yes. 1.4057 is ferromagnetic in every condition: soft annealed, hardened, quenched and tempered. The structure is martensitic rather than austenitic, so unlike 1.4301 / 304 it sticks to a magnet.
What is the difference between +QT800 and +QT900 for 1.4057?
Tempering temperature, and with it the balance between strength and toughness. +QT800 gets a double temper at roughly 750 to 800 °C followed by 650 to 700 °C, which gives Rm 800 to 950 MPa, Rp0.2 of at least 600 MPa and KV of 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 of at least 700 MPa, but KV drops to 16 J. Take +QT800 where toughness matters, +QT900 where strength and wear resistance come first.
Which standard applies to 1.4057 open-die forgings?
EN 10250-4, Open die steel forgings for general engineering purposes, Part 4: Stainless steels. It includes 1.4057. EN 10088-3 supplies the chemical composition and the bar property tables behind it, but its mechanical property table for this grade stops at 160 mm. Beyond that the properties, the test location and the test direction are agreed at the time of order. In North America the corresponding forging specification is ASTM A473 for UNS S43100, with AMS 5628 used 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. Melting, forging, heat treatment, machining and testing all sit on one site in Jiangyin, so single prototype pieces and repeat production batches are both accepted. Send the drawing, or just the size and weight, to sales@steelforgepieces.com.
Can 1.4057 be welded?
It can, 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. 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.
Is 1.4057 suitable for seawater or marine service?
Of the common martensitic stainless steels it handles marine atmospheres best, which is why it turns up so often in pump and propeller shafts at coastal plant. It is not an immersion material. PREN sits around 17.5 to 21.2, and it will pit in saturated sodium chloride and in stagnant seawater at ambient temperature. For continuous immersion, specify a duplex grade such as 1.4462 or a super-austenitic grade instead.
What is the difference between 1.4057 and 1.4021 / 420?
1.4021 / AISI 420 is a plain 13 % chromium martensitic steel with no deliberate nickel. 1.4057 carries 15.0 to 17.0 % chromium plus 1.50 to 2.50 % nickel. That raises corrosion resistance, helps heavy sections harden right through, and lifts impact toughness noticeably in the quenched and tempered condition. On an open-die forging of any real section thickness 1.4057 is normally the better choice. 1.4021 wins where higher hardness and lower cost outweigh toughness.
Which certificates do you supply with 1.4057 forgings?
An EN 10204 3.1 inspection certificate goes with every 1.4057 forging as standard, covering the heat analysis, the heat-treatment record and the mechanical test results. EN 10204 3.2 countersigned by a third party is available on request, and the works is used to surveys by CCS, BV, DNV, LR and NK. Ultrasonic testing to EN 10228-3, dye penetrant testing, a hardness survey and grain-size or intergranular-corrosion testing can all be added to the order.
Which tempering temperatures should be avoided for 1.4057?
Keep the steel out of roughly 400 to 550 °C. This is the 475 °C embrittlement band: notched-bar impact energy falls off sharply and corrosion resistance suffers as well. Producer datasheets advise moving quickly through 420 to 520 °C on cooling. Neither the +QT800 double temper nor the 600 to 650 °C temper of +QT900 enters that range, which is deliberate.
What is the maximum service temperature of 1.4057?
Normal working range is about −40 °C to +400 °C. Push past 400 °C and the part is approaching its own tempering temperature, so the strength gained from quenching and tempering starts to go. In +QT900 the 0.2 % proof strength falls from 700 MPa at room temperature to roughly 375 MPa at 400 °C.
Standards and sources cited on this page
- EN 10088-3. Stainless steels, Part 3: Technical delivery conditions for semi-finished products, bars, rods, wire, sections and bright products. Source of the composition and mechanical property tables. Standard catalogue entry
- EN 10088-1. Stainless steels, Part 1: List of stainless steels. Source of the physical property values.
- EN 10250-4:2021. Open die steel forgings for general engineering purposes, Part 4: Stainless steels. The delivery standard for the forgings on this page. BSI catalogue entry
- ASTM A473, Standard Specification for Stainless Steel Forgings, covering 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 (3.1 and 3.2 certificates).
- EN 10228-2 and EN 10228-3. Non-destructive testing of steel forgings: penetrant and ultrasonic testing.
- Producer datasheets for 1.4057 / X17CrNi16-2 published by Deutsche Edelstahlwerke (Swiss Steel Group), thyssenkrupp Materials, Dörrenberg Edelstahl, BGH Edelstahl, Rodacciai and Carpenter Technology (Type 431) were cross-checked for the heat-treatment, forging and welding values quoted above.
Published by Jiangyin Jiangnan Metal Co., Ltd., open-die forging works, Jiangyin, Jiangsu, China. Technical content checked against EN 10088-1, EN 10088-3, EN 10250-4 and the producer datasheets listed above. Last reviewed . Values here are for guidance. The binding values on any order are those on the agreed specification and the EN 10204 certificate.