18CrNiMo7-6 vs 31CrMoV9: 49% composition overlap. Significantly different materials serving different application areas.
18CrNiMo7-6 vs 31CrMoV9
Side-by-side chemical composition and mechanical property comparison.
Overview
18CrNiMo7-6
1.6587
Premium Cr-Ni-Mo case-hardening steel for the most demanding gear applications. Excellent core toughness and hardenability for large cross-sections. The standard gear steel for wind turbines, heavy-duty gearboxes, and aerospace gearing.
31CrMoV9
1.8519
THE standard nitriding steel — Cr-Mo-V combination optimized for gas nitriding. Vanadium refines grain and forms hard VN nitrides (surface >750 HV). Better core toughness than 31CrMo12 at similar strength. THE default choice when "nitriding steel" is specified without further detail. Used for crankshafts, gears, spindles, extrusion screws, and precision machine components.
| 18CrNiMo7-6 | 31CrMoV9 | |
|---|---|---|
| Material Number | 1.6587 | 1.8519 |
| Category | Alloy Steel | Alloy Steel |
| Standard | EN 10084 | EN 10085 |
Chemical composition (wt%)
| Element | 18CrNiMo7-6 | 31CrMoV9 | Overlap |
|---|---|---|---|
| C | 0.15–0.21% | 0.27–0.34% | No overlap |
| Si | 0–0.4% | 0–0.4% | OK |
| Mn | 0.5–0.9% | 0.4–0.7% | Partial |
| P | 0–0.025% | 0–0.025% | OK |
Mechanical properties
| Property | 18CrNiMo7-6 | 31CrMoV9 | Unit |
|---|---|---|---|
| hardness_hrc | 58–62 | — | HRC |
| tensile_strength | 1050–1350 | 800–1000 | MPa |
| hardness_hb | ≤ 229 | — | HB |
Compatibility Assessment
18CrNiMo7-6 and 31CrMoV9 have significantly different compositions (49% overlap). These materials are not interchangeable and serve different application areas.
Automated assessment based on composition analysis
Frequently Asked Questions
Is 18CrNiMo7-6 the same as 31CrMoV9?
18CrNiMo7-6 and 31CrMoV9 have a 49% composition overlap. They are generally not directly interchangeable.
Can I replace 18CrNiMo7-6 with 31CrMoV9?
Generally not recommended. The compositions differ significantly (49% overlap). These materials have different alloying concepts and are intended for different applications.
What is the difference between 18CrNiMo7-6 and 31CrMoV9?
The main differences are in the following elements: C, Mn, Cr, Mo. 18CrNiMo7-6 is a Alloy Steel grade, while 31CrMoV9 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.