HAP40 vs CPM M4
CPM M4 is tougher, and the two tie on edge retention, corrosion resistance and ease of sharpening. The differences are small, so the knife itself matters more than the steel.
Who wins each property
Side by side
| HAP40 | CPM M4 | |
|---|---|---|
| Type | High-speed powder steels | High-speed powder steels |
| Hardness | 64–67 HRC | 62–65 HRC |
| Edge retention | 8/10 | 8/10 |
| Toughness | 4/10 | 5/10 |
| Corrosion resistance | 2/10 | 2/10 |
| Ease of sharpening | 3/10 | 3/10 |
| Price tier | Premium | Premium |
| Maker | Hitachi Metals (Proterial) | Crucible |
Composition
| Element | HAP40 | CPM M4 |
|---|---|---|
| Carbon (C) | 1.3 | 1.42 |
| Chromium (Cr) | 4 | 4 |
| Vanadium (V) | 3 | 4 |
| Molybdenum (Mo) | 5 | 5.25 |
| Tungsten (W) | 6 | 5.5 |
| Cobalt (Co) | 8 | — |
| Manganese (Mn) | 0.4 | 0.3 |
| Silicon (Si) | 0.4 | 0.55 |
| Sulfur (S) | — | 0.06 |
Property by property
Edge retention
Both rate 8/10 for edge retention. Vanadium: 3% vs 4%; more vanadium carbide generally means more wear resistance.
Toughness
CPM M4 is tougher: 5/10 against 4/10 for HAP40, a 1-point gap. Typical hardness: 64–67 vs 62–65 HRC; harder blades trade toughness for edge holding.
Corrosion resistance
Both rate 2/10 for corrosion resistance.
Ease of sharpening
Both rate 3/10 for ease of sharpening.
Knives in each steel
HAP40
| Knife | Brand | Blade | Weight | Lock | List price | Buy |
|---|---|---|---|---|---|---|
| Sukenari HAP40 Gyuto 240mm | Sukenari | 9.13" | 6.6 oz | — | — | Blade HQ |
| Hatsukokoro HAP40 Gyuto 210mm | Hatsukokoro | 8.39" | 5.4 oz | — | — | Blade HQ |
CPM M4
| Knife | Brand | Blade | Weight | Lock | List price | Buy |
|---|---|---|---|---|---|---|
| Benchmade Bailout 537GY-1 | Benchmade | 3.38" | 2.7 oz | AXIS lock | $350 | Blade HQ |
Shop HAP40 knives Shop CPM M4 knives
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FAQ
Which is better, HAP40 or CPM M4?
CPM M4 is tougher, and the two tie on edge retention, corrosion resistance and ease of sharpening. The differences are small, so the knife itself matters more than the steel.
Which is harder, HAP40 or CPM M4?
HAP40 is typically run at 64–67 HRC and CPM M4 at 62–65 HRC.
Is HAP40 or CPM M4 more rust resistant?
Neither: both rate 2/10. Both are powder metallurgy high-speed steels.