18CrNiMo7-6
Data under review18CrNiMo7-6 is the EN 10084 case-hardening steel (1.6587) for the largest, most heavily loaded gears in wind, marine and industrial service. Its high Cr-Ni-Mo content keeps case and core properties uniform in very large sections.
Chemical composition
| Element | Content (%) |
|---|---|
| C | 0.15–0.21 |
| Si | ≤0.40 |
| Mn | 0.50–0.90 |
| P | ≤0.025 |
| S | ≤0.035 |
| Cr | 1.50–1.80 |
| Ni | 1.40–1.70 |
| Mo | 0.25–0.35 |
Weight percent, per the governing standard ranges. Actual values per heat are on the mill certificate.
Properties
| Case hardness (carburized) | 58–62 HRC |
| Core tensile strength | 900–1200 MPa (typ.) |
| Density | 7.85 g/cm³ |
Heat treatment
Carburize 900–940 °C; quench 800–830 °C oil; temper 150–200 °C (EN 10084).
Equivalent grades
| Standard | Designation |
|---|---|
| din | 1.6587 (18CrNiMo7-6) |
| aisi | 4320 (near) |
Compare side by side: 18CrNiMo7-6 vs 17CrNiMo6 · 18CrNiMo7-6 vs 4320
Equivalents overlap in chemistry and use but are not always identical — see our equivalents guide before substituting in certified designs.
Applications & Processing
Applications: Wind turbine gearbox gears, marine propulsion gears, heavy industrial transmissions.
Processing: Premium gear practice: controlled carburizing, press or plug quenching for distortion, finish grinding.
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Ask for a quotationVisit NasteelSource: EN 10084 published ranges · Last updated 2026-11-03. Data is indicative — verify critical values against the governing standard and mill certificate before use.