Technical Datasheet
20MnCr5
20MnCr5 Case Hardening Alloy Bright Bar
Case Hardening Alloy Steel
Kalika Enterprises
Bright Bar Manufacturer
Plot No. 12/1, Gut No. 182, Jogeshwari, MIDC Waluj, Chhatrapati Sambhajinagar, Maharashtra 431136, India
+91 94229 27509 · kalikaent9@gmail.com
Higher carbon, higher chromium — for heavier loads and larger sections. 20MnCr5 is the heavier-duty member of the Mn-Cr case hardening family. Carbon rises to 0.17–0.22% and chromium to 1.00–1.30% compared with 16MnCr5, and both changes point in the same direction: more core strength and deeper hardenability.
Also known as: 1.7147 · AISI 5120 · SCr420
Key advantage
Core strength up to 1300 MPa with deeper hardening
Higher carbon and chromium lift core tensile strength well above 16MnCr5 and let larger sections harden properly through. The grade of choice where tooth root stresses or shaft core loads are high.
Chemical composition
EN 10084 / DIN 1.7147, certified per mill test certificate
| Element | Min % | Max % |
|---|---|---|
| C Carbon | 0.170 | 0.220 |
| Si Silicon | — | 0.400 |
| Mn Manganese | 1.100 | 1.400 |
| P Phosphorus | — | 0.035 |
| S Sulphur | — | 0.040 |
| Cr Chromium | 1.000 | 1.300 |
Mechanical properties
Cold Drawn / Annealed (supplied soft for machining)
| Property | Value |
|---|---|
| Hardness as supplied | ≤ 217 HBAnnealed / soft, for machining |
| Case hardness after carburising | 58 – 62 HRC |
| Core Tensile Strength | 1000 – 1300 MPaAfter case hardening |
| Core Yield Strength | 700 MPa min |
| Elongation (A5) | 7 – 9%Core, after case hardening |
Available sizes and tolerances
| Shape | Size range |
|---|---|
| Round | 8 – 65 mm |
| Hex (AF) | 10 – 46 mm |
| Tolerance | h9 / h10 / h11 |
| Standard lengths | 3, 4, 5, 6 metre or cut to size |
ISO 286 tolerance values (µm)
| Size (mm) | h9 | h10 | h11 |
|---|---|---|---|
| over 6 to 10 | −36 | −58 | −90 |
| over 10 to 18 | −43 | −70 | −110 |
| over 18 to 30 | −52 | −84 | −130 |
| over 30 to 50 | −62 | −100 | −160 |
| over 50 to 80 | −74 | −120 | −190 |
Typical applications
- Heavily loaded gears and pinions
- Automotive transmission and differential parts
- Larger section carburised shafts
- Splined shafts and drive components
- Heavy duty bushes, pins and levers
International equivalents
| DIN / EN (Germany) | 20MnCr5 / 1.7147 |
| AISI / SAE (USA) | 5120 |
| JIS (Japan) | SCr420 |
| BS (UK) | 527M20 |
| IS (India) | 20Mn5Cr5 |
Heat treatment guidelines
| Operation | Parameters |
|---|---|
| Soft annealing | 650 – 700 °C, furnace cool — gives ≤ 217 HB for machining |
| Normalising | 880 – 920 °C, cool in still air |
| Carburising | 880 – 980 °C in a carburising atmosphere |
| Hardening | Direct or reheat quench from 820 – 860 °C in oil |
| Tempering | 150 – 200 °C, air cool |
Machinability index
52 Fair
Relative to AISI 1212 = 100
Weldability
Limited
Supply condition
Cold Drawn / Annealed (supplied soft for machining)