M42 vs O1 / 100MnCrW4: 8% composition overlap. Significantly different materials serving different application areas.
M42 vs O1 / 100MnCrW4
Side-by-side chemical composition and mechanical property comparison.
Overview
M42
1.3247
Cobalt super high speed steel — 8% Co for maximum hot hardness (HRC 69 at 550°C). THE HSS for machining superalloys, titanium, and pre-hardened steels where M2 burns out. Mo-series (not W-series like T15). Reaches HRC 68-70 after hardening — among the hardest HSS grades. Also known as HS2-9-1-8 (EN) or SKH59 (JIS). Used for drills, end mills, taps, broaches, and milling cutters for difficult-to-machine materials.
O1 / 100MnCrW4
1.2510
Oil-hardening cold-work tool steel. Good balance of wear resistance, toughness, and machinability at moderate cost. Very predictable heat treatment response. The standard choice for hand tools, gauges, jigs, fixtures, taps, reamers, and general precision tooling.
| M42 | O1 / 100MnCrW4 | |
|---|---|---|
| Material Number | 1.3247 | 1.2510 |
| Category | Tool Steel | Tool Steel |
| Standard | EN ISO 4957 | EN ISO 4957 |
Chemical composition (wt%)
| Element | M42 | O1 / 100MnCrW4 | Overlap |
|---|---|---|---|
| C | 1.05–1.15% | 0.9–1.05% | Partial |
| Si | 0–0.65% | 0.1–0.4% | OK |
| Mn | 0–0.4% | 1–1.2% | No overlap |
| P | 0–0.03% | — | — |
Mechanical properties
| Property | M42 | O1 / 100MnCrW4 | Unit |
|---|---|---|---|
| hardness_hrc | 68–70 | 57–62 | HRC |
| e_modulus | ≥ 210 | ≥ 210 | GPa |
| density | ≥ 7.98 | ≥ 7.83 | g/cm3 |
Compatibility Assessment
M42 and O1 / 100MnCrW4 have significantly different compositions (8% overlap). These materials are not interchangeable and serve different application areas.
Automated assessment based on composition analysis
Frequently Asked Questions
Is M42 the same as O1 / 100MnCrW4?
M42 and O1 / 100MnCrW4 have a 8% composition overlap. They are generally not directly interchangeable.
Can I replace M42 with O1 / 100MnCrW4?
Generally not recommended. The compositions differ significantly (8% overlap). These materials have different alloying concepts and are intended for different applications.
What is the difference between M42 and O1 / 100MnCrW4?
The main differences are in the following elements: C, Mn, Cr, V. M42 is a Tool Steel grade, while O1 / 100MnCrW4 is a Tool Steel grade.
View full data for each material:
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.