CPM-4V is a high-performance powder metallurgy tool steel produced by Crucible Industries. It is designed to be the "middle ground" in the V-series, sitting perfectly between the extreme toughness of CPM-3V and the extreme wear resistance of CPM-10V.
In the knife community, it is often called a "super-charged" version of 3V or a tougher version of Cru-Wear.
Key Characteristics
High Wear Resistance: With significantly more Vanadium and Carbon than 3V, it holds a sharp edge much longer. It is excellent for tasks that require sustained cutting through abrasive materials.
Outstanding Toughness: While not quite as unbreakable as 3V, it is still exceptionally tough—far tougher than D2, M390, or S30V. It can handle heavy-duty use and impact without the edge chipping.
High Attainable Hardness: It is typically heat-treated to 60–62 HRC, but can be pushed to 64 HRC. This high hardness helps prevent the edge from "rolling" during hard work.
Non-Stainless (Semi-Stainless): Like its siblings, it has about 5% Chromium. It will rust if not maintained. It is a tool steel that requires oiling or a protective coating (like DLC) to prevent corrosion.
Fine Grain Structure: Thanks to the CPM process, it takes a very aggressive, "toothy" edge that is excellent for slicing.
Chemical Composition
Carbon (C): 1.35% (Significantly higher than 3V for better hardness)
Chromium (Cr): 5.00% (For hardenability and wear resistance)
Vanadium (V): 3.85% (Provides the high wear resistance)
Molybdenum (Mo): 2.95% (Increases strength and toughness)
Common Applications
Competition Cutting Knives: 4V is a dominant steel in "BladeSports" competitions because it can survive chopping through 2x4s while remaining sharp enough to shave hair afterward.
Hard-Use EDC Folders: Used by brands like Spyderco (often in "St. Nick’s Knives" exclusives) for users who want more edge retention than 3V but more toughness than M4.
Premium Fixed Blades: Ideal for hunting and tactical knives that need to perform under high stress.
Comparison: 4V vs. CPM Cru-Wear
These two are very similar in performance:
CPM-4V typically has a slight edge in pure wear resistance (edge holding).
CPM Cru-Wear is generally considered a bit easier to sharpen and slightly more stable during heat treatment.