Materials & grades
4150 / 50CrMo4 / 1.7228 chromium-molybdenum steel
SAE 4150 is a higher-carbon chromium-molybdenum alloy steel with 0.48–0.53% carbon, used hardened and tempered for shafts, gears and firearm barrels. Its European equivalent is 50CrMo4 (1.7228), and SCM445 is the nearest Japanese grade.
Names by standard
What it is called in each region
| Region | System | Designation | תקן | Match |
|---|---|---|---|---|
| USA | AISI/SAE | 4150 | SAE J404; ASTM A29 (bar) | Same material |
| UNS | G41500 | — | Same material | |
| AISI/SAE | 4150HHardenability-band version. DEW lists 4150H alongside 4150 against 50CrMo4. | SAE hardenability-band grade | Closest equivalent | |
| UK | BS 970 (1970 series) | 708A47Printed by Saarstahl as the British name for 50CrMo4. Not confirmed in the BS 970 text. DEW prints 708M50 instead, so the two mills disagree. | BS 970-1 | Closest equivalent |
| BS 970 | 708M50Printed by DEW against 50CrMo4 and AISI 4147/4150. Not confirmed in the BS 970 text; check the drawing before substituting. | BS 970 | Closest equivalent | |
| EU | EN 10027-1 name | 50CrMo4The same name was used in the superseded DIN 17200. | EN 10083-3; EN ISO 683-2 | Equivalent |
| EN 10027-2 number | 1.7228 | EN 10083-3 | Equivalent | |
| Japan | JIS G 4053 | SCM445Carbon is 0.43–0.48%, below the 4150 range. DEW lists SCM445 against 50CrMo4 and 4150; Kobelco lists it against 4145 and 4147. | JIS G 4053 | Closest equivalent |
| JIS G 4052 | SCM445HHardenability-guaranteed version. DEW lists SCM445H against 50CrMo4. | JIS G 4052 | Closest equivalent |
On equivalence
- 4150 and 50CrMo4 are close equivalents, not the same specification. 50CrMo4 allows 0.46–0.54% carbon, 0.50–0.80% manganese, 0.90–1.20% chromium and 0.15–0.30% molybdenum; 4150 specifies 0.48–0.53% carbon, 0.75–1.00% manganese, 0.80–1.10% chromium and 0.15–0.25% molybdenum.
- UK: Saarstahl prints 708A47 for 50CrMo4 and DEW prints 708M50. Neither was confirmed in the BS 970 text, so both are "closest". 708M40 is the 4140 grade, not this one.
- Japan: SCM445 has 0.43–0.48% carbon, below 4150. DEW lists SCM445 against 50CrMo4 and 4150, and Kobelco lists it against 4145 and 4147.
- India: IS 1570 (Part 4):1988 lists no chromium-molybdenum grade at about 0.50% carbon. 50Cr4 has 0.45–0.55% carbon and 0.90–1.20% chromium but no molybdenum, so it is not a like-for-like substitute. No Indian notation is given.
- DEW also lists 4147 and 4147H against 50CrMo4. 4147 is not covered on this site.
- Silicon: AZoM gives 0.15–0.30% for 4150, while the Central Steel & Wire catalog (via Wikipedia) gives 0.15–0.35%.
- The EN 10083-3 property values apply to the diameter and condition shown. Compare equivalents at the same section size.
Chemical composition
Composition limits, mass %
| Element | 4150USA · SAE J404 / ASTM A29 (bar) | 50CrMo4 (1.7228)EU · EN 10083-3 (cast analysis, as printed by DEW) | SCM445 (closest match)Japan · JIS G 4053 (as tabulated by Kobelco) |
|---|---|---|---|
| C | 0.48–0.53 | 0.46–0.54 | 0.43–0.48 |
| Si | 0.15–0.35 | ≤0.40 | 0.15–0.35 |
| Mn | 0.75–1.00 | 0.50–0.80 | 0.60–0.90 |
| P | ≤0.035 | — | ≤0.030 |
| S | ≤0.040 | — | ≤0.030 |
| Cr | 0.80–1.10 | 0.90–1.20 | 0.90–1.20 |
| Ni | — | — | ≤0.25 |
| Mo | 0.15–0.25 | 0.15–0.30 | 0.15–0.30 |
Mechanical properties
Strength and hardness
| Condition | Tensile strength | Yield strength | Elongation | Hardness |
|---|---|---|---|---|
| AnnealedTypical values, not specified minimumsAZoM, AISI 4150 alloy steel (UNS G41500) | 731 MPa106.0 ksi | 380 MPa55.1 ksi | 20.2 % | 197 HB |
| Soft annealed (+A)Specified maximum hardnessEN 10083-3, 50CrMo4, via DEW and Saarstahl datasheets | — | — | — | ≤248 HB |
| Quenched and tempered (+QT)Diameter ≤16 mm (thickness <8 mm); yield and elongation are minimums; Z ≥40%, KV ≥30 JEN 10083-3, 50CrMo4, via Saarstahl and DEW datasheets | 1100–1300 MPa160–189 ksi | ≥900 MPa≥131 ksi | ≥9 % | — |
| Quenched and tempered (+QT)Diameter 16–40 mm (thickness 8–20 mm); yield and elongation are minimums; Z ≥45%, KV ≥30 JEN 10083-3, 50CrMo4, via Saarstahl and DEW datasheets | 1000–1200 MPa145–174 ksi | ≥780 MPa≥113 ksi | ≥10 % | — |
| Quenched and tempered (+QT)Diameter 40–100 mm (thickness 20–60 mm); yield and elongation are minimums; Z ≥50%, KV ≥30 JEN 10083-3, 50CrMo4, via Saarstahl and DEW datasheets | 900–1100 MPa131–160 ksi | ≥700 MPa≥102 ksi | ≥12 % | — |
| Quenched and tempered (+QT)Diameter 100–160 mm (thickness 60–100 mm); yield and elongation are minimums; Z ≥50%, KV ≥30 JEN 10083-3, 50CrMo4, via Saarstahl and DEW datasheets | 850–1000 MPa123–145 ksi | ≥650 MPa≥94 ksi | ≥13 % | — |
| Quenched and tempered (+QT)Diameter 160–250 mm (thickness 100–160 mm); yield and elongation are minimums; Z ≥50%, KV ≥30 JEN 10083-3, 50CrMo4, via Saarstahl and DEW datasheets | 800–950 MPa116–138 ksi | ≥550 MPa≥80 ksi | ≥13 % | — |
In practice
Behaviour, heat treatment and uses
Characteristics
- Carbon of 0.48–0.53% makes 4150 the highest-carbon member of the 41xx chromium-molybdenum series covered here, with the same 0.80–1.10% chromium and 0.15–0.25% molybdenum as 4140.
- Saarstahl describes 50CrMo4 as a chromium-molybdenum quenching and tempering steel for strengths of 900–1200 MPa, for parts needing high toughness.
- Machinability is rated 55 (AISI 1212 = 100) for annealed and cold drawn bar (AZoM, typical). AZoM calls machinability good when annealed or normalized and formability good when annealed.
- Weldability is poor. DEW states that 50CrMo4 is not weldable and should not be used in welded constructions. AZoM says 4150 can be welded by conventional methods but advises post-weld heat treatment and an approved procedure, and warns that welding the hardened steel changes its properties.
- Transformation temperatures for 50CrMo4 (DEW): Ms 300 °C, Ac1 745 °C, Ac3 775 °C.
Heat treatment
- Hot forming (50CrMo4, DEW): 1100–850 °C, then slow cooling. Saarstahl gives forging or rolling at 1050–850 °C.
- Normalizing: 840–880 °C, then air cool (DEW). Saarstahl gives 850–880 °C. US practice (AZoM): 899 °C.
- Soft annealing: 680–720 °C with furnace cooling gives 248 HB maximum (DEW, Saarstahl). AZoM gives 899 °C with slow furnace cooling for the US annealed condition.
- Hardening: 820–850 °C in water, or 830–860 °C in oil or an equivalent polymer quench (DEW). Saarstahl gives 820–860 °C in oil. AZoM lists 816 °C with a water quench.
- Tempering: 540–680 °C with air cooling for the EN 10083-3 property ranges (DEW, Saarstahl). AZoM gives 205–649 °C depending on the hardness wanted; higher temperatures lower the hardness.
- AZoM forging range: 983–1205 °C. Hot working: 872–1038 °C.
שימושים אופייניים
- Shafts, axles, spindles and control parts (Saarstahl)
- Rings, bands and bushes for automotive and aircraft work where toughness matters (Saarstahl)
- Through-hardening parts for vehicle and general mechanical engineering (DEW)
- Firearm barrels: 4150 is one of the steels accepted for US military M16 and M4 barrels (Wikipedia, 41xx steel)
Alloy and case-hardening steels
Similar grades compared
| דרגה | C % | Mn % | Cr % | Ni % | Tensile, first listed condition |
|---|---|---|---|---|---|
| 4150 / 50CrMo4 | 0.48–0.53 | 0.75–1.00 | 0.80–1.10 | ≤0.25 | 731 MPa |
| 4130 / 25CrMo4 | 0.28–0.33 | 0.40–0.60 | 0.80–1.10 | ≤0.25 | 590–760 MPa |
| 4135 / 34CrMo4 | 0.33–0.38 | 0.70–0.90 | 0.80–1.10 | ≤0.25 | 1000–1200 MPa |
| 4140 / 42CrMo4 | 0.38–0.43 | 0.75–1.00 | 0.80–1.10 | ≤0.25 | 655 MPa |
| 4145 | 0.43–0.48 | 0.75–1.00 | 0.80–1.10 | ≤0.25 | ≥965 MPa |
| 4340 / EN24 | 0.38–0.43 | 0.60–0.80 | 0.70–0.90 | 1.65–2.00 | 745 MPa |
| 5140 / 41Cr4 | 0.38–0.43 | 0.70–0.90 | 0.70–0.90 | ≤0.25 | 570 MPa |
| 6150 / 51CrV4 | 0.48–0.53 | 0.70–0.90 | 0.80–1.10 | ≤0.40 | 670 MPa |
| 8640 / SNCM240 | 0.38–0.43 | 0.75–1.00 | 0.40–0.60 | 0.40–0.70 | 1000–1413 MPa |
| 16MnCr5 | 0.13–0.18 | 0.70–0.90 | 0.70–0.90 | ≤0.25 | ≥1000 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 is the equivalent of 4150 steel?
The European equivalent is 50CrMo4 (1.7228). The nearest Japanese grade is SCM445, and the UK names printed by mills are 708A47 or 708M50. The grades overlap but are not identical, so check the limits when a drawing calls for one standard.
What is the difference between 4140 and 4150?
Carbon. 4150 holds 0.48–0.53% carbon and 4140 holds 0.38–0.43%, with the same manganese, chromium and molybdenum limits. 4150 reaches higher hardness and strength after quenching and tempering and is harder to weld.
Is 4150 the same as 50CrMo4?
They are equivalent grades, not the same specification. 50CrMo4 allows 0.46–0.54% carbon and 0.90–1.20% chromium, while 4150 specifies 0.48–0.53% carbon and 0.80–1.10% chromium. A heat can often be certified to both, but each certificate cites one standard.
Can 4150 steel be welded?
Poorly. DEW says 50CrMo4 is not weldable, and AZoM advises post-weld heat treatment for 4150. Weld repair needs a qualified procedure with preheat and post-weld heat treatment, and welding the hardened steel changes its local properties.
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Related references
References
Sources
- Saarstahl, Werkstoff-Datenblatt 50CrMo4 (1.7228) — International designations (BS 708A47, SAE 4150), +QT properties by diameter, heat treatment.
- Deutsche Edelstahlwerke (Swiss Steel Group), Werkstoffdatenblatt 1.7228 / 50CrMo4 — EN composition, designation table (AISI 4147/4150, BS 708M50, JIS SCM445), properties, weldability statement, heat treatment.
- AZoM, AISI 4150 Alloy Steel (UNS G41500) — Composition, typical annealed properties, heat treatment, machinability, welding.
- SAE J404: Chemical compositions of SAE alloy steels — Governs the SAE alloy-steel composition limits. Values here are as tabulated by AZoM and the Central Steel & Wire catalog.
- Wikipedia, 41xx steel (SAE composition table citing the Central Steel & Wire catalog) — SAE bar composition for 4145 and 4150; example applications.
- Kobelco: wire rod and bar specification tables (JIS G 4053 alloy steels for machine structure, revision of 20 Nov 2008; JIS G 4107 bolting steels) — JIS composition tables and the JIS-to-ISO/AISI cross-reference table.
- IS 1570 (Part 4):1988 Schedules for wrought steels, alloy steels (public copy) — Table 1 composition limits and the footnote cross-references to AISI and DIN grades.
Values summarize published limits and typical data. The governing standard and the current edition control; check them before specifying.