CPM-S90V (formerly known as CPM-420V) is a high-alloy powder metallurgy stainless steel produced by Crucible Industries. It is widely regarded as one of the ultimate "super steels" for edge retention.
While S30V and S35VN are balanced all-rounders, S90V is a specialized high-performance steel designed for users who want their knives to stay sharp for an incredibly long time.
Key Characteristics
Top-Tier Edge Retention: S90V contains a massive amount of Vanadium (9%), which creates a high density of hard vanadium carbides. In terms of pure cutting longevity, it significantly outperforms S30V, S35VN, and even M390.
Exceptional Wear Resistance: It is designed to resist abrasion. If you are slicing through high volumes of cardboard, rope, or abrasive materials, S90V is one of the best choices available.
High Corrosion Resistance: With 14% Chromium, it is very rust-resistant. Despite its high carbon and vanadium content, it holds up extremely well in wet or humid environments.
Lower Toughness: The trade-off for its extreme edge holding is that it is relatively brittle. It is prone to micro-chipping if it hits a hard object or is used for prying. It is a dedicated slicer, not a hard-use tool.
Very Difficult to Sharpen: S90V is notorious for being a "stone eater." Because the vanadium carbides are harder than standard sharpening stones, you must use diamond or CBN abrasives to maintain it effectively.
Chemical Composition
Carbon (C): 2.30% (Extremely high to support the high vanadium content)
Chromium (Cr): 14.00% (For rust resistance)
Vanadium (V): 9.00% (The "secret" to its legendary edge life)
Molybdenum (Mo): 1.00%
Common Applications
Premium Folding Knives: Used by brands like Benchmade (e.g., the 940-1 Osborne and the Bugout 535-3) and Spyderco (in various premium versions of the PM2 and Manix 2).
High-End Slicing Tools: Ideal for hunters who need to skin multiple animals without stopping to sharpen.
Comparison: S90V vs. S110V
S90V is generally considered slightly easier to sharpen and marginally tougher than S110V.
S110V offers even more edge retention and better corrosion resistance but is more brittle.