40NiCrMo7 vs 39NiCrMo3: Same family — 40NiCrMo7 has 2x the Ni for larger sections
40NiCrMo7 vs 39NiCrMo3
Side-by-side chemical composition and mechanical property comparison.
Overview
40NiCrMo7
1.6563
High-nickel Cr-Mo quench & temper steel for large cross-sections. 1.6-2.0% Ni gives superior hardenability compared to 39NiCrMo3 — through-hardening up to ~130mm diameter. Close to AISI 4340 composition. Used for heavy crankshafts, large gears, turbine shafts, connecting rods, and critical structural fasteners in energy and heavy machinery sectors.
39NiCrMo3
1.6510
Nickel-chromium-molybdenum quench & temper steel. Similar to AISI 4340 but with lower Ni — more economical. Good hardenability for sections up to ~80mm. Excellent balance of strength, toughness, and fatigue resistance. High white-point sensitivity — hydrogen control required. Used for crankshafts, connecting rods, gear shafts, landing gear components, and heavy-duty machinery parts.
| 40NiCrMo7 | 39NiCrMo3 | |
|---|---|---|
| Material Number | 1.6563 | 1.6510 |
| Category | Alloy Steel | Alloy Steel |
| Standard | EN 10083-3 | EN 10083-3 |
Chemical composition (wt%)
| Element | 40NiCrMo7 | 39NiCrMo3 | Overlap |
|---|---|---|---|
| C | 0.37–0.44% | 0.35–0.43% | Partial |
| Si | 0–0.4% | 0–0.4% | OK |
| Mn | 0.5–0.8% | 0.5–0.8% | OK |
| P | 0–0.025% | 0–0.025% | OK |
Mechanical properties
| Property | 40NiCrMo7 | 39NiCrMo3 | Unit |
|---|---|---|---|
| tensile_strength | 980–1180 | 900–1200 | MPa |
| yield_strength | 780–835 | 600–800 | MPa |
| elongation | 10–14 | 10–16 | % |
Compatibility Assessment
40NiCrMo7 has 1.6-2.0% Ni vs 0.7-1.0% in 39NiCrMo3, enabling through-hardening up to ~130mm vs ~80mm. Very close to AISI 4340. Higher Ni = higher cost. Choose 40NiCrMo7 for sections >80mm or critical rotating parts; 39NiCrMo3 for smaller/economical applications.
Frequently Asked Questions
Is 40NiCrMo7 the same as 39NiCrMo3?
40NiCrMo7 and 39NiCrMo3 have a 75% composition overlap. Same family — 40NiCrMo7 has 2x the Ni for larger sections
Can I replace 40NiCrMo7 with 39NiCrMo3?
In many cases, yes. The compositions overlap significantly (75%). However, always verify mechanical property requirements and heat treatment compatibility for your specific application.
What is the difference between 40NiCrMo7 and 39NiCrMo3?
The main differences are in the following elements: C, Cr, Mo, Ni. 40NiCrMo7 is a Alloy Steel grade, while 39NiCrMo3 is a Alloy Steel grade.
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Data provided for reference only. Always verify against the applicable specification for critical applications.
All data is for reference only. Equivalents indicate similarity, not identity. Always verify against the applicable specification for safety-critical applications. materialref.com accepts no liability for decisions based on this data.