Materials & grades
431 / 1.4057 / SUS431 martensitic stainless steel: equivalents 431S29 and X17CrNi16-2
431 is a nickel-bearing 16 % chromium martensitic stainless steel with the best corrosion resistance and toughness of the hardenable 400 series. Its equivalents are 1.4057 (X17CrNi16-2) in Europe, 431S29 in the UK, X15Cr16Ni2 in India and SUS431 in Japan.
Names by standard
What it is called in each region
| Region | System | Designation | Norma | Match |
|---|---|---|---|---|
| USA | AISI/ASTM | 431 | ASTM A276 (bar) | Same material |
| UNS | S43100 | — | Same material | |
| UK | BS 970-3 (1991) | 431S29Stainless grades are no longer in BS 970; new orders use EN 10088-3. The name is still used on drawings. | BS 970-3 | Equivalent |
| BS 970 (1955 EN series) | EN57Superseded 1955 name listed against 431S29 by Aalco and Aircraft Materials. | — | Closest equivalent | |
| EU | EN 10027-1 name | X17CrNi16-2Carbon 0.12–0.22 %, chromium 15–17 %, nickel 1.5–2.5 %. | EN 10088-1; EN 10088-3 | Equivalent |
| EN 10027-2 number | 1.4057Material number of X17CrNi16-2. | EN 10088-1; EN 10088-3 | Equivalent | |
| DIN 17440 (legacy) | X20CrNi17 2Superseded German name for 1.4057 (listed by West Yorkshire Steel), still seen on older drawings. | DIN 17440 | Equivalent | |
| India | IS 1570 (Part 5) | X15Cr16Ni2Carbon 0.10–0.20 %, nickel 1.25–2.50 %, chromium 15–17 %. | IS 1570 (Part 5):1985 | Equivalent |
| Japan | JIS G 4303 | SUS431Same carbon, chromium and nickel limits as ASTM 431. | JIS G 4303 | Equivalent |
On equivalence
- 431, 1.4057 and SUS431 are close equivalents. EN states carbon 0.12–0.22 % where ASTM and JIS set a maximum of 0.20 % and IS sets 0.10–0.20 %.
- The Indian designation is X15Cr16Ni2, which is named from the nominal carbon, not from the EN name X17CrNi16-2.
- 431S29 is the BS 970 name. The superseded 1955 number is EN57. Deutsche Edelstahlwerke also lists 321S31 against it, which looks like a mistake.
- The older German name X20CrNi17 2 is superseded by X17CrNi16-2.
- Impact values differ by source. Dörrenberg gives the DIN EN 10088-3:2014-12 values: QT800 ≥25 J up to 60 mm and ≥20 J for 60–160 mm, QT900 ≥16 J up to 60 mm and ≥15 J for 60–160 mm. Deutsche Edelstahlwerke lists ≥25 J for both conditions. The table above uses the Dörrenberg values.
- ASTM A276 lists 431 only in Condition A. Condition T is a supply condition under AS 1444 and BS 970, so test limits depend on the specification ordered.
Chemical composition
Composition limits, mass %
| Element | 431USA · ASTM A276 | X17CrNi16-2 (1.4057)EU · EN 10088-3 | X15Cr16Ni2India · IS 1570 (Part 5):1985 | SUS431Japan · JIS G 4303 |
|---|---|---|---|---|
| C | ≤0.20 | 0.12–0.22 | 0.10–0.20 | ≤0.20 |
| Si | ≤1.00 | ≤1.00 | ≤1.0 | ≤1.00 |
| Mn | ≤1.00 | ≤1.50 | ≤1.0 | ≤1.00 |
| P | ≤0.040 | ≤0.040 | ≤0.045 | ≤0.040 |
| S | ≤0.030 | ≤0.030 | ≤0.030 | ≤0.030 |
| Cr | 15.0–17.0 | 15.0–17.0 | 15.0–17.0 | 15.00–17.00 |
| Ni | 1.25–2.50 | 1.5–2.5 | 1.25–2.50 | 1.25–2.50 |
Mechanical properties
Strength and hardness
| Condition | Tensile strength | Yield strength | Elongation | Hardness |
|---|---|---|---|---|
| Annealed (Condition A)Typical tensile values; hardness is the specified maximum (ASTM A276). Rarely supplied annealedAtlas Steels 431 data sheet | 862 MPa125 ksi | 655 MPa95 ksi | 20 % | ≤285 HB |
| Condition T (hardened and tempered)Tensile range as supplied to AS 1444 and BS 970; yield and elongation are minimumsAtlas Steels 431 data sheet | 850–1000 MPa123–145 ksi | ≥635 MPa≥92 ksi | ≥11 % | 248–302 HB |
| Hardened and tempered at 300 °CTypical values, not minimumsAtlas Steels 431 data sheet | 1320 MPa191 ksi | 1020 MPa148 ksi | 20 % | 380 HB |
| Hardened and tempered at 600 °CTypical values, not minimumsAtlas Steels 431 data sheet | 1030 MPa149 ksi | 800 MPa116 ksi | 20 % | 310 HB |
| Quenched and tempered +QT800Specified, bar up to 60 mm; elongation is ≥12 % for 60–160 mmEN 10088-3 as given by Dörrenberg (DIN EN 10088-3:2014-12) and Deutsche Edelstahlwerke | 800–950 MPa116–138 ksi | ≥600 MPa≥87 ksi | ≥14 % | Impact ≥25 J up to 60 mm, ≥20 J for 60–160 mm (ISO-V) |
| Quenched and tempered +QT900Specified, bar up to 60 mm; elongation is ≥10 % for 60–160 mmEN 10088-3 as given by Dörrenberg (DIN EN 10088-3:2014-12) and Deutsche Edelstahlwerke | 900–1050 MPa131–152 ksi | ≥700 MPa≥102 ksi | ≥12 % | Impact ≥16 J up to 60 mm, ≥15 J for 60–160 mm (ISO-V) |
| Hardened and tempered (X15Cr16Ni2)Specified, sheet, plate, strip, bar and flatIS 1570 (Part 5):1985, Table 4 | 830–1030 MPa120–149 ksi | ≥640 MPa≥93 ksi | ≥10 % | — |
| Hardened and tempered (SUS431)Specified minimums, bar; reduction of area ≥40 %JIS G 4303 as given by Nose Stainless | ≥780 MPa≥113 ksi | ≥590 MPa≥86 ksi | ≥15 % | ≥229 HBW (annealed ≤302 HBW) |
In practice
Behaviour, heat treatment and uses
Characteristics
- Heat treatable to high strength and toughness, with hardness up to about 40 HRC (Atlas). Used for shafts and bolts.
- About 16 % chromium and 2 % nickel give the best corrosion resistance in the hardenable martensitic group. Overall it is about equal to or slightly below 304 (Atlas).
- Reasonable resistance to cold sea water, unlikely to succeed in warm tropical water (Atlas). Resistance is best hardened and tempered with a smooth finish.
- Susceptible to intergranular corrosion through chromium carbide formation (Marks, DEW). Check after welding.
- Ferromagnetic, like all martensitic grades.
- Atlas rates welding as difficult because of cracking risk, while Deutsche Edelstahlwerke rates 1.4057 weldability as good. Both call for preheat and post-weld heat treatment. Atlas gives preheat of 200–300 °C and heat treatment at 650 °C afterwards, and says 308L, 309 or 310 fillers give more ductile welds if matching strength is not needed.
- High yield strength makes it a poor choice for cold heading, bending, deep drawing or spinning. Machinability is fair annealed and falls as hardness rises.
Heat treatment
- Annealing: full annealing is not practical because the steel hardens even on slow cooling. Process anneal at about 620–660 °C, air cool (Atlas). DEW gives soft annealing at 680–800 °C.
- Hardening: about 980–1065 °C, hold about half an hour, quench in air or oil (Atlas). DEW gives 950–1060 °C. Preheating at 760–790 °C helps complex parts.
- Tempering to suit properties. QT800: 750–800 °C then 650–700 °C, or a single 620–720 °C temper at the low-nickel end. QT900: 600–650 °C (DEW).
- Avoid tempering between about 425 and 600 °C (Atlas) or 420 and 520 °C (DEW) because of reduced toughness.
- Hot forming: heat slowly to about 850 °C, then to 1150–1180 °C; forge between about 1180 and 950 °C (DEW).
Usos habituales
- Propeller and pump shafting
- Nuts and bolts and marine hardware
- Beater bars
- Aerospace and automotive parts
- Pump, turbine and chemical-plant components
Stainless steels
Similar grades compared
| Grado | C % | Mn % | Cr % | Ni % | Tensile, first listed condition |
|---|---|---|---|---|---|
| 431 / 1.4057 | ≤0.20 | ≤1.00 | 15.0–17.0 | 1.25–2.50 | 862 MPa |
| 410 / 1.4006 | 0.08–0.15 | ≤1.00 | 11.5–13.5 | ≤0.75 | ≥480 MPa |
| 420 / 1.4021 | ≥0.15 | ≤1.00 | 12.0–14.0 | ≤1.0 | 655 MPa |
| 201 / 1.4372 | ≤0.15 | 5.50–7.50 | 16.0–18.0 | 3.5–5.5 | ≥515 MPa |
| 301 / 1.4310 | ≤0.15 | ≤2.00 | 16.0–18.0 | 6.0–8.0 | ≥515 MPa |
| 303 / 1.4305 | ≤0.15 | ≤2.0 | 17.0–19.0 | 8.0–10.0 | 650 MPa |
| 304 / 1.4301 | ≤0.08 | ≤2.00 | 18.0–20.0 | 8.0–10.5 | ≥515 MPa |
| 304L / 1.4307 | ≤0.030 | ≤2.00 | 18.0–20.0 | 8.0–12.0 | ≥485 MPa |
| 309 / 309S | ≤0.08 | ≤2.00 | 22.0–24.0 | 12.0–15.0 | ≥515 MPa |
| 310 / 310S | ≤0.08 | ≤2.00 | 24.0–26.0 | 19.0–22.0 | ≥515 MPa |
Composition from the US standard where one exists, otherwise the first standard listed on each grade's page. Strength conditions differ between grades; open a grade for its full table.
Preguntas resueltas
Common questions
What is the difference between 431 and 410 stainless steel?
431 has about 16 % chromium and 2 % nickel. 410 has about 12 % chromium and no nickel. 431 resists corrosion better and is tougher and stronger when hardened. It is also harder to weld and costs more.
Is 431 stainless steel magnetic?
Yes. 431 is martensitic and ferromagnetic in every condition, even though it contains nickel. Only fully austenitic grades such as 304 and 316 are non-magnetic when annealed.
What is the equivalent of 431 stainless steel?
1.4057 (X17CrNi16-2) in the EN standards, 431S29 in the old British standard, X15Cr16Ni2 in IS 1570 and SUS431 in JIS. Limits for carbon differ slightly between them.
Is 431 as corrosion resistant as 304?
Roughly. Atlas gives 431 as about equal to or slightly below 304 in general corrosion, and best when hardened, tempered and polished. 304 is better in chloride environments and far easier to weld.
Can 431 stainless steel be welded?
With care. Atlas rates it difficult because of cracking risk, and Deutsche Edelstahlwerke rates 1.4057 as good. Both call for preheat and post-weld heat treatment. Atlas gives preheat of 200–300 °C and heat treatment at about 650 °C afterwards, with 410 filler to match strength or 308L, 309 or 310 for a more ductile joint.
From the Corona catalog
Need a part made to this specification?
Send the drawing, the material or grade, the finish, the quantity and the delivery country. The team reviews the requirement and the manufacturing route.
Iniciar una consultaKeep reading
Related references
References
Sources
- Atlas Steels, Stainless Steel 431 Grade Data Sheet (revised 28/04/2021) — ASTM A276 composition and Condition A, Condition T, tempering table, heat treatment, welding, corrosion.
- Deutsche Edelstahlwerke (Swiss Steel Group), 1.4057 X17CrNi16-2 data sheet — EN 10088-3 QT800 and QT900, composition headline, heat treatment, corrosion, BS and DIN cross-reference.
- Dörrenberg Edelstahl, 1.4057 X17CrNi16-2 data sheet (DIN EN 10088-3:2014-12 values, 02/24) — Independent check: QT800 and QT900 elongation by diameter (≤60 mm and 60–160 mm). Source of the impact values (ISO-V) by diameter.
- Zhejiang Guanyu (tubingchina.com): EN 10088-3 mechanical properties of martensitic and precipitation-hardening long products — Independent check: 1.4057 QT800 and QT900 elongation split at 60 mm.
- Outokumpu: Steel Grades, Properties and Global Standards — EN, ASTM, UNS, JIS and BS cross-reference; EN and ASTM minimum properties for flat products.
- Nose Stainless: steel types, composition and mechanical properties (JIS G 4303 reference sheet) — JIS G 4303 composition, heat treatment and mechanical properties for bar. Catalog reproducing the JIS values.
- Bureau of Indian Standards, IS 1570 (Part 5):1985 Schedules for wrought steels, stainless and heat-resisting steels (Public.Resource.Org copy) — Table 1 composition, Tables 2 to 4 mechanical properties and Table 7 heat treatment.
- Atlas Steels Technical Handbook of Stainless Steels (revised 12/08/2021) — Grade comparison (BS, EN, JIS), magnetic response and family characteristics. Distributor handbook quoting ASTM values.
- Aalco: stainless steel EN standards for bar — BS 970 designations with the superseded 1955 EN numbers (56A, 56B, 56D, 57, 60). Stockist table.
- Aircraft Materials: cross-reference of stainless steel specifications — BS and EN numbers (EN56C, EN57, EN60, BS 318S13) against AISI grades. Trade reference.
- West Yorkshire Steel: international stainless steel cross-reference — BS 970, W.Nr, DIN, JIS and AFNOR cross-reference. Stockist table.
- MARKS GmbH: Werkstoff-Datenblatt 1.4057 X17CrNi16-2 — EN limits for silicon, manganese, phosphorus and sulphur; corrosion and weld notes.
Values summarize published limits and typical data. The governing standard and the current edition control; check them before specifying.