Materials & grades
17-4PH / 630 / 1.4542 precipitation-hardening stainless steel: S17400, X5CrNiCuNb16-4 and SUS630
17-4PH is a martensitic precipitation-hardening stainless steel with 17 % chromium, 4 % nickel and 4 % copper that ages to over 1300 MPa tensile strength. It is also called Type 630 or UNS S17400, and its equivalents are 1.4542 (X5CrNiCuNb16-4) and SUS630.
Names by standard
What it is called in each region
| Region | System | Designation | תקן | Match |
|---|---|---|---|---|
| USA | AISI/ASTM | 630Type 630 and 17-4PH are the same grade (Atlas). | ASTM A564 (bar, wire, shapes); ASTM A693 (plate, sheet, strip) | Same material |
| Common name | 17-4PHTrade name for Type 630, from the 17 % chromium and 4 % nickel. | — | Same material | |
| UNS | S17400 | — | Same material | |
| EU | EN 10027-1 name | X5CrNiCuNb16-4Silicon, manganese and sulphur limits differ slightly from ASTM A564. | EN 10088-1; EN 10088-2; EN 10088-3 | Equivalent |
| EN 10027-2 number | 1.4542Material number of X5CrNiCuNb16-4. The remelted aerospace variant is 1.4548. | EN 10088-1; EN 10088-2; EN 10088-3 | Equivalent | |
| Japan | JIS G 4303 | SUS630Composition matches ASTM 630. JIS names conditions S, H900, H1025, H1075 and H1150. | JIS G 4303 (bar); JIS G 4304 / G 4305 (plate, sheet) | Equivalent |
On equivalence
- 17-4PH, Type 630, UNS S17400 and AISI 630 are the same steel. 1.4542 and SUS630 are the usual equivalents. EN allows silicon up to 0.70 % and manganese up to 1.50 %, and sets sulphur at 0.015 %. ASTM A564 allows silicon and manganese up to 1.00 % and sulphur 0.030 %.
- No UK designation is listed. BS 970 had no 17-4PH grade, and Atlas and Aircraft Materials show no BS entry. UK buyers specify 1.4542 or ASTM A564 and the aerospace specification.
- No Indian designation appears in IS 1570 (Part 5). Indian buyers order against ASTM A564, EN 10088 or JIS and name the condition.
- Condition names differ. ASTM and JIS use H900, H1025 and H1150, while EN uses +P800, +P930, +P960 and +P1070 for bar and P850, P950 and P1070 for flat products.
- JIS SUS630 H900 yield is 1175 MPa against 1170 MPa in ASTM A564. Check the specification ordered.
- Aerospace specifications (AMS 5643, AMS 5622 for the remelted grade) add requirements beyond the commercial standards.
Chemical composition
Composition limits, mass %
| Element | 630 (S17400)USA · ASTM A564 / A693 | X5CrNiCuNb16-4 (1.4542)EU · EN 10088-1 | SUS630Japan · JIS G 4303 |
|---|---|---|---|
| C | ≤0.07 | ≤0.07 | ≤0.07 |
| Si | ≤1.00 | ≤0.70 | ≤1.00 |
| Mn | ≤1.00 | ≤1.50 | ≤1.00 |
| P | ≤0.040 | ≤0.040 | ≤0.040 |
| S | ≤0.030 | ≤0.015 (≤0.030 bar) | ≤0.030 |
| Cr | 15.0–17.5 | 15.0–17.0 | 15.50–17.50 |
| Ni | 3.0–5.0 | 3.0–5.0 | 3.00–5.00 |
| Mo | — | ≤0.60 | — |
| Cu | 3.0–5.0 | 3.0–5.0 | 3.00–5.00 |
| Nb | — | 5×C–0.45 | 0.15–0.45 |
| Nb+Ta | 0.15–0.45 | — | — |
Mechanical properties
Strength and hardness
| Condition | Tensile strength | Yield strength | Elongation | Hardness |
|---|---|---|---|---|
| Condition A (solution treated)Typical values; hardness is a maximumASTM A564M as quoted by Atlas Steels | 1105 MPa160 ksi | 1000 MPa145 ksi | 15 % | ≤38 HRC (≤363 HB) |
| H900 (aged at 480 °C, 1 h)Specified minimums, bar; hardness is a minimumASTM A564M as quoted by Atlas Steels | ≥1310 MPa≥190 ksi | ≥1170 MPa≥170 ksi | ≥10 % | ≥40 HRC (388 HB) |
| H925 (aged at 495 °C, 4 h)Specified minimums, barASTM A564M as quoted by Atlas Steels | ≥1170 MPa≥170 ksi | ≥1070 MPa≥155 ksi | ≥10 % | ≥38 HRC (375 HB) |
| H1025 (aged at 550 °C, 4 h)Specified minimums, barASTM A564M as quoted by Atlas Steels | ≥1070 MPa≥155 ksi | ≥1000 MPa≥145 ksi | ≥12 % | ≥35 HRC (331 HB) |
| H1075 (aged at 580 °C, 4 h)Specified minimums, barASTM A564M as quoted by Atlas Steels | ≥1000 MPa≥145 ksi | ≥860 MPa≥125 ksi | ≥13 % | ≥32 HRC (311 HB) |
| H1100 (aged at 595 °C, 4 h)Specified minimums, barASTM A564M as quoted by Atlas Steels | ≥965 MPa≥140 ksi | ≥795 MPa≥115 ksi | ≥14 % | ≥31 HRC (302 HB) |
| H1150 (aged at 620 °C, 4 h)Specified minimums, barASTM A564M as quoted by Atlas Steels | ≥930 MPa≥135 ksi | ≥725 MPa≥105 ksi | ≥16 % | ≥28 HRC (277 HB) |
| H900 (SUS630)Specified minimums, bar; reduction of area ≥40 %JIS G 4303 as given by Nose Stainless | ≥1310 MPa≥190 ksi | ≥1175 MPa≥170 ksi | ≥10 % | ≥40 HRC (≥375 HBW) |
| H1150 (SUS630)Specified minimums, bar; reduction of area ≥50 %JIS G 4303 as given by Nose Stainless | ≥930 MPa≥135 ksi | ≥725 MPa≥105 ksi | ≥16 % | ≥28 HRC (≥277 HBW) |
| Aged to P1070 (1.4542)Specified minimums, plate up to 50 mm; elongation A for ≥3 mmEN 10088-2 as tabulated by Euro Inox | 1070–1270 MPa155–184 ksi | ≥1000 MPa≥145 ksi | ≥10 % | — |
| Aged to P950 (1.4542)Specified minimums, plate up to 50 mm; elongation A for ≥3 mmEN 10088-2 as tabulated by Euro Inox | 950–1150 MPa138–167 ksi | ≥800 MPa≥116 ksi | ≥12 % | — |
| Aged to P850 (1.4542)Specified minimums, plate up to 50 mm; elongation A for ≥3 mmEN 10088-2 as tabulated by Euro Inox | 850–1050 MPa123–152 ksi | ≥600 MPa≥87 ksi | ≥14 % | — |
| Solution treated and aged 4 h at 550 °C (X17U4)Typical values, not minimumsAubert & Duval X17U4 data sheet | 1070 MPa155 ksi | 1000 MPa145 ksi | 10 % | Impact 120 J (KV) |
| Solution treated and aged 4 h at 620 °C (X17U4)Typical values, not minimumsAubert & Duval X17U4 data sheet | 950 MPa138 ksi | 750 MPa109 ksi | 16 % | Impact 140 J (KV) |
In practice
Behaviour, heat treatment and uses
Characteristics
- Supplied solution treated, when it is just machinable. One low-temperature aging treatment then hardens it with no significant distortion (Atlas). This suits long shafts that cannot be re-straightened.
- Shrinks slightly on aging, about 0.05 % for H900 and 0.10 % for H1150 (Atlas).
- Condition names follow the aging temperature in °F: H900 is aged at about 480 °C and H1150 at about 620 °C. Higher aging gives lower strength, higher toughness and better stress-corrosion resistance.
- Corrosion resistance approaches 304 (Atlas). It pits and crevice-corrodes in warm chloride water. It has been used for fresh-water boat shafts and, with cathodic protection, in sea water.
- Highly resistant to stress corrosion cracking if aged at 550 °C or above. NACE MR0175 allows 630 only in a double-aged condition (Atlas).
- Do not use the solution-treated condition in service. It has lower stress-corrosion resistance and lower ductility than the aged conditions.
- Martensitic and magnetic. Weldable by standard methods without preheat; post-weld aging restores near-parent properties (Atlas). Machinability is similar to 304. Avoid long exposure at 370–480 °C if toughness matters.
Heat treatment
- Solution treatment (Condition A): about 1040 °C for half an hour, cool in air to below 30 °C. Oil quenching is possible for small non-intricate sections (Atlas). EN sources give 1000–1050 °C and JIS gives 1020–1060 °C.
- H900: age about 480 °C for 1 hour, air cool. JIS gives 470–490 °C.
- H1025: age about 550 °C for 4 hours, air cool. JIS gives 540–560 °C.
- H1150: age about 620 °C for 4 hours, air cool. JIS gives 610–630 °C. Double-aged H1150M and H1150D are specified separately in ASTM A564.
- Aubert & Duval name the two common routes as 4 hours at 550 °C (1070 MPa) and 4 hours at 620 °C (950 MPa). Aging for 1 hour at about 480 °C gives about 1300 MPa but raises stress-corrosion risk.
שימושים אופייניים
- High-strength pump and boat propeller shafts
- Gears, bolts and valve components
- Plastic moulding dies
- Engine and aerospace components
- Parts needing corrosion resistance with high strength or hardness
Stainless steels
Similar grades compared
| דרגה | C % | Mn % | Cr % | Ni % | Tensile, first listed condition |
|---|---|---|---|---|---|
| 17-4PH / 630 | ≤0.07 | ≤1.00 | 15.0–17.5 | 3.0–5.0 | 1105 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 |
| 316 / 1.4401 | ≤0.08 | ≤2.00 | 16.0–18.0 | 10.0–14.0 | ≥515 MPa |
| 316L | ≤0.030 | ≤2.00 | 16.0–18.0 | 10.0–14.0 | ≥485 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.
תשובות לשאלות
Common questions
What do H900, H1025 and H1150 mean for 17-4PH?
They name the aging temperature in °F after solution treatment. H900 is aged at about 480 °C and gives the highest strength (at least 1310 MPa, 40 HRC). H1025 is about 550 °C and H1150 about 620 °C, giving lower strength (at least 930 MPa for H1150) but better toughness and stress-corrosion resistance.
Is 17-4PH stainless steel magnetic?
Yes. 17-4PH is martensitic and ferromagnetic in the solution-treated and aged conditions, like 410, 420 and 431.
What is the equivalent of 17-4PH?
1.4542 (X5CrNiCuNb16-4) in Europe and SUS630 in Japan. 630 and S17400 are the same grade as 17-4PH. There is no BS 970 or IS 1570 equivalent.
What is the difference between 17-4PH and 304 or 316?
17-4PH is much stronger, reaching over 1300 MPa after aging, and can be hardened with one low-temperature treatment. Corrosion resistance is about the same as 304 and below 316. 304 and 316 are non-magnetic when annealed and cannot be heat hardened.
Can 17-4PH be welded?
Yes, by standard methods and usually without preheat. Age the weld after welding to restore properties near the parent metal. Design to avoid concentration of weld stresses.
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Related references
References
Sources
- Atlas Steels, Stainless Steel 630 (17-4PH) Grade Data Sheet (revised 28/04/2021) — ASTM A564M composition and H-condition properties, corrosion, heat treatment, welding.
- Aubert & Duval: X17U4 (X5CrNiCuNb16-4) data sheet — Typical properties for 550 and 620 °C aging, heat treatment and impact values.
- Euro Inox, Stainless Steel: Tables of Technical Properties (2nd edition, 2007) — EN 10088 composition limits and EN 10088-2 flat-product mechanical properties.
- 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.
- 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.
- Aircraft Materials: cross-reference of stainless steel specifications — BS and EN numbers (EN56C, EN57, EN60, BS 318S13) against AISI grades. Trade reference.
- MARKS GmbH: Werkstoffblatt 1.4542 X5CrNiCuNb16-4 — EN 10088 aging condition names (+P800, +P930, +P960, +P1070) and heat treatment routes.
Values summarize published limits and typical data. The governing standard and the current edition control; check them before specifying.