SCr420
Data verifiedSCr420 is the chromium-only carburizing steel of JIS G4053, the Japanese counterpart of AISI 5120. Without molybdenum it is the economy case steel for small gears and shafts in Japanese and Asian drivetrains.
Chemical composition
| Element | Content (%) |
|---|---|
| C | 0.18–0.23 |
| Si | 0.15–0.35 |
| Mn | 0.60–0.90 |
| P | ≤0.030 |
| S | ≤0.030 |
| Cr | 0.90–1.20 |
Weight percent, per the governing standard ranges. Actual values per heat are on the mill certificate.
Properties
| Case hardness (carburized) | 58–63 HRC |
| Density | 7.85 g/cm³ |
Heat treatment
Carburize 900–930 °C; quench ≈850 °C oil; temper 150–200 °C.
Equivalent grades
| Standard | Designation |
|---|---|
| din | 1.7027 (20Cr4, near) |
| aisi | 5120 |
| jis | SCr420 (JIS G4053) |
| gb | 20Cr |
Compare side by side: SCr420 vs 5120 · SCr420 vs SCM420
Equivalents overlap in chemistry and use but are not always identical — see our equivalents guide before substituting in certified designs.
Applications & Processing
Applications: Small gears and pinions, drive shafts, chain parts, case-hardened bushings.
Processing: Machines well soft; case depth control as for 5120/20MnCr5 practice, with somewhat lower core hardenability than the Cr-Mo grades.
FAQ
- SCr420 vs SCM420?
- SCM420 adds 0.15–0.25% molybdenum: better core hardenability and case uniformity on larger sections, at higher cost. SCr420 covers small case parts economically.
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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.