Steel Grade Datasheet
20MnCr5/ 1.7147 / 5120Chromium-Manganese Case-Hardening Steel
What is 20MnCr5 steel?
20MnCr5 (Werkstoff No. 1.7147, equivalent to AISI 5120) is a chromium-manganese case-hardening (carburizing) steel — the heavier sibling of 16MnCr5 with higher carbon, manganese and chromium. This higher alloying gives deeper case hardening and higher core strength. After carburizing the surface reaches 58–62 HRC — the material for heavy-duty transmission gears and large-section parts.
Chemical Composition
Cast analysis, % by weight (per the applicable EN standard)
| Element | Range (%) |
|---|---|
| C | 0.17–0.22 |
| Si | ≤ 0.40 |
| Mn | 1.10–1.40 |
| P | ≤ 0.025 |
| S | ≤ 0.035 |
| Cr | 1.00–1.30 |
Mechanical Properties (kör sertleştirilmiş (çekirdek) / blank-hardened core)
Values depend on ruling section / thickness (d).
| Section (mm) | Yield Re min (MPa) | Tensile Rm (MPa) | Elongation A min (%) |
|---|---|---|---|
| d ≤ 11 | 850 | 1100–1400 | 7 |
| 11 < d ≤ 30 | 700 | 980–1280 | 8 |
| 30 < d ≤ 63 | 550 | 780–1080 | 9 |
Hardness: +A (annealed): ≤ 217 HB (machinable) · Carburized surface: 58–62 HRC · Core: higher strength than 16MnCr5
20MnCr5 / 1.7147 properties and use
International Equivalents
Values marked ≈ are nearest matches, not exact equivalents. Always confirm against the governing standard.
| System | Grade |
|---|---|
| EN | 20MnCr5 |
| W.-Nr. (DIN) | 1.7147 |
| AISI/SAE | 5120 |
| ASTM | A29 (5120) |
| JIS | ≈ SCr420 / SMnC420 |
| GOST | ≈ 18ХГТ (18KhGT) |
| BS (UK) | ≈ 590M17 |
| GB (China) | ≈ 20CrMnTi |
Applications
- Heavy-duty transmission and gearbox gears
- Large-section gear wheels and pinions
- Camshafts and drive shafts
- Differential gears
- Heavy machinery drivetrain parts
- Carburized bushings and pins
Available Product Forms
Frequently Asked Questions
What is the difference between 20MnCr5 and 16MnCr5?+
20MnCr5 has higher carbon (0.17–0.22% vs 0.14–0.19%), manganese and chromium, giving deeper case hardening and higher core strength. 16MnCr5 is ideal for small-to-medium gears, while 20MnCr5 is preferred for heavier-loaded, large-section gears.
What surface hardness does 20MnCr5 reach?+
After carburizing and quenching the surface is 58–62 HRC. Case hardening depth (CHD) is usually set between 0.3 and 1.5 mm; 20MnCr5's higher alloying gives a deeper, more durable case.
Is 20MnCr5 the same as AISI 5120?+
For practical purposes yes; 20MnCr5 is the European (EN) and 5120 the American (AISI/SAE) designation, used interchangeably as a chromium-manganese case-hardening steel. For critical work follow the ordering standard's ranges.
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References & Standards
Values on this page are reference data compiled from the applicable EN standard; certified material properties are defined by the mill test certificate (EN 10204 3.1).