SNCM220
Data verifiedSNCM220 is the JIS Ni-Cr-Mo carburizing steel — the exact JIS designation of the AISI 8620 gear steel concept, and also cross-referenced to the 4320 family. It is the standard Japanese case steel for transmission gears needing a hard case over a fatigue-resistant core.
Chemical composition
| Element | Content (%) |
|---|---|
| C | 0.17–0.23 |
| Si | 0.15–0.35 |
| Mn | 0.60–0.90 |
| P | ≤0.030 |
| S | ≤0.030 |
| Cr | 0.60–0.90 |
| Ni | 0.40–0.70 |
| Mo | 0.15–0.25 |
Weight percent, per the governing standard ranges. Actual values per heat are on the mill certificate.
Properties
| Case hardness (carburized) | 58–63 HRC |
| Core tensile | 700–950 MPa |
| Density | 7.85 g/cm³ |
Heat treatment
Carburize 900–930 °C; quench ≈850 °C oil; temper 150–200 °C.
Equivalent grades
| Standard | Designation |
|---|---|
| din | 1.6523 (21NiCrMo2-2, near) |
| aisi | 8620 |
| jis | SNCM220 (JIS G4053) |
| gb | 20CrNiMo |
Compare side by side: SNCM220 vs 4320 · SNCM220 vs 8620
Equivalents overlap in chemistry and use but are not always identical — see our equivalents guide before substituting in certified designs.
Applications & Processing
Applications: Transmission gears and pinions, camshafts, drive shafts, high-duty case-hardened components.
Processing: As 8620: excellent machinability before carburizing; finish-grind after hardening; case depth 0.5–1.5 mm typical.
FAQ
- SNCM220 = 8620?
- Yes for practical purposes — JIS G4053 SNCM220 and SAE 8620 have near-identical composition windows and the same carburizing practice. The JIS name is what appears on Asian mill certificates.
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Ask for a quotationVisit NasteelSource: JIS G4053 published ranges · Last updated 2026-11-03. Data is indicative — verify critical values against the governing standard and mill certificate before use.