CPM S90V

CPM S90V is what happens when a steel is designed around one question: how long can an edge keep cutting? Crucible’s answer packs 9% vanadium and 2.3% carbon into a powder-metallurgy stainless whose carbide volume out-wears essentially every mainstream blade steel — a working edge that survives cardboard, rope and abrasive media for absurd stretches. Everything else about S90V is the bill for that answer: it grinds slowly, sharpens grudgingly, chips before it bends, and costs accordingly. It is a specialist’s steel, and it is honest about it.

CPM S90V FAQ

Is CPM S90V a good knife steel?

For dedicated slicers whose owners prize edge retention above all — yes, nearly unmatched. The vanadium carbide population is so dense that in standardized cutting tests S90V lands at the top of the stainless chart, clearly above M390 and 20CV. It is the wrong steel for hard use, batoning, tips that pry, or owners who sharpen on basic stones.

How hard is S90V to sharpen?

This is the famous cost. Vanadium carbide is harder than aluminum-oxide and silicon-carbide abrasives — conventional stones polish the steel matrix around the carbides rather than cutting them, which is why S90V has a reputation for taking a “good enough” edge reluctantly. Diamond and CBN abrasives change the experience completely: with diamond plates, S90V sharpens slowly but normally. Sell or buy this steel with the diamond-stone conversation attached; details in our S90V grinding guide.

What hardness should S90V be run at?

59–61 HRC typical, up to 62 for pure slicers with careful protocol. Austenitize per Crucible’s sheet (commonly 2050–2150°F depending on target), plate quench, cold treat, temper — the same kiln-and-protocol discipline as every high-alloy PM stainless, covered in our heat treat guide. Stock removal only; nobody forges 9% vanadium on purpose.

Is S90V tough?

No — and it does not pretend. That carbide volume leaves modest impact toughness; thin edges chip on staples and bones that MagnaCut or 3V would shrug off. The design answer is geometry: S90V wants sensible edge angles (18-20 dps) and slicing duty, where its wear resistance gets to matter and its brittleness never comes up.

Is S90V stainless?

Yes, in practical terms. Around 14% chromium delivers real stain resistance for EDC and kitchen service — below M390’s margin and far below LC200N’s immunity, but rust is a non-issue with normal care.

S90V or M390?

S90V cuts longer; M390 does everything else a little better — tougher, easier to sharpen, easier to find, cheaper. For a pure cardboard-and-rope slicer, S90V earns its premium; for a general premium EDC, M390/20CV is the saner pick. Full breakdown: S90V vs M390.

Also known as: CPM S90V (Crucible); predecessor designation CPM 420V; European cousin: Bohler M398 (higher carbide take on the recipe)

Composition

Carbon 2.30%, Chromium 14.0%, Vanadium 9.00%, Molybdenum 1.00%, Silicon 0.50%, Manganese 0.50%

Properties

PropertyRatingNotes
Toughness★☆☆☆☆The bill for the vanadium. S90V sits near the bottom of the stainless toughness chart - thin edges chip on impact, tips do not tolerate prying, and batoning is out of the question. Geometry compensates: keep angles at 18-20 dps and duty strictly slicing and it behaves for years.
Edge Retention★★★★★The entire point, and the rating undersells it - this is the top of the stainless wear chart. Nine percent vanadium forms extremely hard MC carbides that keep a working edge through abrasive media long after M390-class steels have gone dull. In CATRA-style testing only exotic siblings (S110V, M398, Maxamet-class) keep company.
Corrosion Resistance★★★★☆Practically stainless for EDC and kitchen life - about 14% chromium, enough free in the matrix for real protection. Below M390's margin; wipe after salt exposure and it will never trouble you.
Machinability / Grinding★☆☆☆☆The shop pays for the edge. Annealed S90V drills and grinds slowly even with sharp ceramics; hardened, it defeats conventional abrasives outright - fresh ceramic belts for grinding, diamond/CBN for every sharpening task. Budget double the belts and triple the patience of a normal stainless, and keep it cool: burning an edge you spent this long grinding hurts twice.

Heat Treatment

Stock removal only, kiln required. Foil-wrap and austenitize per Crucible’s datasheet (commonly 2050-2150°F by target hardness), plate quench, cold treat promptly (dry ice minimum) to convert retained austenite, temper twice at 400-500°F for 59-61 HRC. High-heat protocols with 1000°F tempers exist for maximum hardness; most makers run the low-temper route. Send it out if any of this sounds optional.

Best Uses

Dedicated EDC and utility slicers, cardboard-and-rope working knives, hunting blades for owners with diamond stones, collector-grade folders where the spec sheet is the story. Not for choppers, prying tips, or basic-stone households.

Sources: Crucible CPM S90V datasheet; Knife Steel Nerds vanadium carbide and edge retention testing (knifesteelnerds.com); Spydiewiki CPM-S90V entry; maker consensus from BladeForums S90V threads.