23MnB4 vs 31CrMoV9: 60% composition overlap. Moderate differences, generally not direct substitutes.
23MnB4 vs 31CrMoV9
Side-by-side chemical composition and mechanical property comparison.
Overview
23MnB4
1.5535
Cold-heading boron steel — optimized for cold forming of high-strength fasteners. Boron gives hardenability equivalent to much more expensive Cr-Mo alloys. Supplied spheroidized for cold heading, then quenched+tempered after forming. Property class 10.9 bolts are commonly made from this grade. Used for high-strength bolts (M8-M24), screws, studs, and threaded fasteners for automotive and construction.
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.
| 23MnB4 | 31CrMoV9 | |
|---|---|---|
| Material Number | 1.5535 | 1.8519 |
| Category | Alloy Steel | Alloy Steel |
| Standard | EN 10263-4 | EN 10085 |
Chemical composition (wt%)
| Element | 23MnB4 | 31CrMoV9 | Overlap |
|---|---|---|---|
| C | 0.2–0.27% | 0.27–0.34% | Partial |
| Si | 0–0.4% | 0–0.4% | OK |
| Mn | 0.8–1.1% | 0.4–0.7% | No overlap |
| P | 0–0.025% | 0–0.025% | OK |
Mechanical properties
| Property | 23MnB4 | 31CrMoV9 | Unit |
|---|---|---|---|
| tensile_strength | 830–1040 | 800–1000 | MPa |
| yield_strength | 660–830 | 600–750 | MPa |
| elongation | 9–14 | 12–16 | % |
Compatibility Assessment
23MnB4 and 31CrMoV9 have moderate differences (60% overlap). They are generally not direct substitutes. Consider the specific requirements of your application.
Automated assessment based on composition analysis
Frequently Asked Questions
Is 23MnB4 the same as 31CrMoV9?
23MnB4 and 31CrMoV9 have a 60% composition overlap. They are generally not directly interchangeable.
Can I replace 23MnB4 with 31CrMoV9?
Generally not recommended. The compositions differ significantly (60% overlap). These materials have different alloying concepts and are intended for different applications.
What is the difference between 23MnB4 and 31CrMoV9?
The main differences are in the following elements: C, Mn. 23MnB4 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.