20Cr
Data verified20Cr is China’s basic carburizing chromium steel (GB/T 3077), the counterpart of AISI 5120 and JIS SCr420 for case-hardened gears and shafts.
Chemical composition
| Element | Content (%) |
|---|---|
| C | 0.17–0.24 |
| Si | 0.17–0.37 |
| Mn | 0.50–0.80 |
| P | ≤0.035 |
| S | ≤0.035 |
| Cr | 0.70–1.00 |
Weight percent, per the governing standard ranges. Actual values per heat are on the mill certificate.
Properties
| Tensile strength | ≥835 MPa (GB/T 3077 reference Q&T) |
| Yield strength | ≥540 MPa (reference) |
| Case hardness (carburized) | 58–62 HRC |
| Density | 7.85 g/cm³ |
Heat treatment
Carburize 900–930 °C; quench 800–830 °C oil; temper 150–200 °C. Or Q&T for low-duty parts.
Equivalent grades
| Standard | Designation |
|---|---|
| din | 1.7027 (20Cr4) |
| aisi | 5120 |
| jis | SCr420 |
| gb | 20Cr (GB/T 3077) |
Compare side by side: 20Cr vs 5120
Equivalents overlap in chemistry and use but are not always identical — see our equivalents guide before substituting in certified designs.
Applications & Processing
Applications: Gears, pinions, shafts, worms, carburized bushings.
Processing: Machines well before carburizing; finish-grind after.
Need 20Cr from stock?
Steel.Wiki is sponsored by Shenzhen NewAsia Special Steel (Nasteel), a special-steel stockholder in Shenzhen stocking mold, tool and alloy steels with EN 10204 3.1 certification.
Ask for a quotationVisit NasteelSource: GB/T 3077 published ranges · Last updated 2026-11-03. Data is indicative — verify critical values against the governing standard and mill certificate before use.