S30V Blade Steel
CPM (Crucible Particle Metallurgy ) S30V, released in 2001 by Crucible Steel, is one of the main steels Apex Steel Works utilizes for it’s knives. It’s tough, especially considering it’s stainless, has an excellent fine edge potential with noticeable carbide content leading to long edge life between maintenance operations, and holds it’s surface finish to an excellent degree with no staining or discoloration over time. It is suitable from everything from hunting knives, as well as bowies and hard use EDC knives to skinning knives due to it’s extreme edge retention and carbide content.
CPM S30V steel is a martensitic stainless tool steel with properties that make it very appropriate for hard use kitchen, survival and hunting knives. It is highly corrosion resistant with a chromium content of 14.00% classifying it as a fully stainless grade of steel, indicating almost total resistance to moisture or chemical attack (~5 times greater than 440C) by common agents a knife would be subject to.
Other alloying elements include vanadium (4.00%) and molybdenum (2.00%) with the very precise particle metallurgy process used by Crucible producing a homogenous steel with evenly distributed fine carbines throughout. The ratio between these two alloying elements is very finely controlled in this steel allowing for a predominance of vanadium rather than chromium in the carbides formed during heat treatment. The molybdenum increasing corrosion resistance in concert with the chromium and S30V is a nitrogen-added steel which also adds to it’s stainless nature, aids in heat treat response and helps vanadium carbides dominate in the matrix rather than softer chromium precipitation.
The steel is tough, very much so for a stainless alloy, and in die and tool applications has little change between it’s annealed or hardened state – or at varying temperatures while in use allowing predictable machining layouts and less estimation of size-change while engineering items which will be made from it.
In functional use it’s toughness is four times that of 440C or 154CM leading to excellent resistance against chipping and edge damage. The nature of the carbides at typical hardness for a hunting knife at 60-61 Rockwell or bushcraft knife (58-59 Rockwell) allows for edge retention 20-50% greater than 440C or 154CM as well.
One caveat using the steel is that as it has a strong carbide structure, high polish applications are limited. The carbides dislodge from the hardened steel matrix and scuff and gall the surface during fine grit finishing or buffing application – so a satin finish, machine or hand applied – or other surface treatments are appropriate. It is also proportionately more difficult to sharpen, although with modern stones, diamond abrasives and guided fixed-angle sharpeners this has been mitigated to a great deal.
Apex Steel Works heat treats CPM S30V per Crucible’s published documentation regarding austenitizing temperatures and hold times, with a plate quench followed by cryogenic treatment then temper protocol suitable for the size and application of the knife. Aim hardness for small hunting knives with fine terminal edges is 60-61 Rockwell C whereas larger chopping and general purpose hard-use knives will be tempered at a higher temperature to 58-59 Rockwell C to optimize the toughness of the steel.
It is an excellent benchmark steel for many applications, and it’s combination of corrosion resistance, vanadium carbides for long lasting edge retention along with high relative toughness for a stainless tool steel all combine to make it an excellent choice for a hunting knife in particular.