4815
Data verified4815 is a high-nickel (3.5%) Ni-Mo carburizing steel for premium gears needing maximum core toughness and case fatigue resistance at low temperature. Its alloy cost confines it to aerospace and high-end industrial gearing.
Chemical composition
| Element | Content (%) |
|---|---|
| C | 0.13–0.18 |
| Si | 0.15–0.35 |
| Mn | 0.40–0.60 |
| P | ≤0.035 |
| S | ≤0.040 |
| Ni | 3.25–3.75 |
| Mo | 0.20–0.30 |
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 | 800–1050 MPa (typ.) |
| Density | 7.85 g/cm³ |
Heat treatment
Carburize 890–920 °C; quench 790–820 °C oil; temper 150–190 °C; sub-zero treatment improves case stability.
Equivalent grades
| Standard | Designation |
|---|---|
| aisi | 4815 |
Compare side by side: 4815 vs 4820
Equivalents overlap in chemistry and use but are not always identical — see our equivalents guide before substituting in certified designs.
Applications & Processing
Applications: Aerospace gears, high-duty transmission gears, precision pinions.
Processing: Retains austenite readily — sub-zero cooling after quench is standard practice; grind with care.
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Ask for a quotationVisit NasteelSource: SAE J404 published ranges · Last updated 2026-11-03. Data is indicative — verify critical values against the governing standard and mill certificate before use.