40CrNiMo6 vs 34CrNiMo6: Same Cr-Ni-Mo family — 40CrNiMo6 is higher C for more strength
40CrNiMo6 vs 34CrNiMo6
Side-by-side chemical composition and mechanical property comparison.
Overview
40CrNiMo6
1.6565
High-strength Cr-Ni-Mo quench and temper steel. Higher C than 34CrNiMo6 for greater strength, with excellent hardenability from Ni+Mo combination. Used for heavy-duty crankshafts, connecting rods, high-strength bolts (class 12.9), gears, and critical structural components in large cross-sections.
34CrNiMo6
1.6582
High-strength quenched and tempered Cr-Ni-Mo steel. Excellent hardenability and toughness, suitable for large cross-sections. Used for heavy-duty shafts, gears, turbine parts, and aerospace components.
| 40CrNiMo6 | 34CrNiMo6 | |
|---|---|---|
| Material Number | 1.6565 | 1.6582 |
| Category | Alloy Steel | Alloy Steel |
| Standard | EN 10083-3 | EN 10083-3 |
Chemical composition (wt%)
| Element | 40CrNiMo6 | 34CrNiMo6 | Overlap |
|---|---|---|---|
| C | 0.36–0.44% | 0.3–0.38% | 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 | 40CrNiMo6 | 34CrNiMo6 | Unit |
|---|---|---|---|
| tensile_strength | 1000–1200 | 1000–1200 | MPa |
| yield_strength | ≥ 800 | ≥ 800 | MPa |
| elongation | ≥ 10 | ≥ 11 | % |
Compatibility Assessment
40CrNiMo6 reaches 1000-1200 MPa UTS (vs 900-1100 for 34CrNiMo6). 34CrNiMo6 is tougher and more widely available. Choose 40CrNiMo6 for class 12.9 bolts and maximum strength; 34CrNiMo6 for general high-strength QT.
Frequently Asked Questions
Is 40CrNiMo6 the same as 34CrNiMo6?
40CrNiMo6 and 34CrNiMo6 have a 85% composition overlap. Same Cr-Ni-Mo family — 40CrNiMo6 is higher C for more strength
Can I replace 40CrNiMo6 with 34CrNiMo6?
In many cases, yes. The compositions overlap significantly (85%). However, always verify mechanical property requirements and heat treatment compatibility for your specific application.
What is the difference between 40CrNiMo6 and 34CrNiMo6?
The main differences are in the following elements: C, Cr. 40CrNiMo6 is a Alloy Steel grade, while 34CrNiMo6 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.