CPM S90V is a high-performance stainless steel renowned for its outstanding wear resistance and edge retention. Developed by Crucible Industries using the Crucible Particle Metallurgy (CPM) process, it emerged in response to the ongoing demand for steels that balance hardness and corrosion resistance at high hardness levels. Though it has been on the market for some time, CPM S90V remains highly relevant in modern knife-making, particularly for advanced enthusiasts and collectors who value knives with exceptionally long-lasting edges. Since its introduction, it has found regular use in premium everyday carry (EDC) blades, hunting knives, and limited-edition collector pieces.
In the broader landscape of premium steels, CPM S90V often stands alongside other powder metallurgy steels that strive for superior performance, such as CPM 3V, M390, or S30V. Each has its own set of strengths. In the case of CPM S90V, the spotlight frequently shines on its excellent edge retention and very good corrosion resistance. This steel’s presence in notable production knives, combined with its consistent performance in industry-standard tests, underscores why it continues to be held in high regard.
At its core, CPM S90V is formulated to maximize wear resistance through the abundant inclusion of carbon and vanadium carbides, while retaining sufficient levels of chromium for corrosion resistance. The typical composition is as follows:
Carbon contributes directly to hardness and the formation of wear-resistant carbides. The relatively high carbon content in CPM S90V allows for a high as-quenched hardness, which is central to its excellent edge retention. Chromium, at 14%, classifies this alloy as stainless, granting it very good corrosion resistance in most typical environments. Molybdenum aids in secondary hardening and can improve the steel’s overall toughness, while also enhancing corrosion resistance. The standout feature is the large dose of vanadium, which supports the creation of numerous small, hard vanadium carbides that boost wear resistance and edge stability. In CPM S90V, these carbides become uniformly distributed throughout the steel thanks to the powder metallurgy process, enhancing both edge retention and overall cutting performance.
Another metallurgical asset arises from the CPM method itself. Unlike conventional ingot steelmaking, the powder-based technique involves atomizing molten steel into microscopic particles and then consolidating them under high pressure. This approach minimizes segregation of alloying elements, leading to improved grain refinement and a uniform carbide structure. As a result, CPM S90V is known for consistent performance, with less risk of large carbide clusters that could act as stress concentrators.
Although CPM S90V is often shaped via stock-removal processes due to its high carbide content, it can be forged under the right conditions:
Hot Forging
Cold Forging
Common pitfalls in forging CPM S90V include improper temperature control and working the steel too aggressively. The large volume of carbides makes the steel work-harden quickly, so repeated hammering without adequate re-heating can lead to internal stresses. Most professional smiths recommend forging at the upper end of safe forging temperatures and following with thorough thermal cycling to minimize residual stress.
Heat treatment is pivotal to extracting the best properties from CPM S90V. The recommended austenitizing (hardening) range typically spans from about 2050°F (1120°C) to 2150°F (1177°C), although specific protocols vary among professional heat-treating facilities. Many industry experts favor higher austenitizing temperatures to further dissolve carbides and achieve maximum hardness, but care must be taken not to overshoot temperatures, as this can adversely affect toughness.
Quenching for CPM S90V can be carried out in oil, but more commonly, an accelerated gas or air quench is used in professional settings to minimize distortion and the potential formation of undesirable microstructures.
After quenching, the steel requires one or more tempering cycles to optimize the final hardness and toughness balance. A typical tempering temperature falls somewhere between 400°F (204°C) and 600°F (316°C), depending on the desired hardness. Multiple tempers are common to ensure full stress relief and microstructural stability.
Below is a simplified table showing approximate hardness levels for CPM S90V based on varying austenitizing temperatures, assuming a single temper at about 500°F (260°C). These figures are provided only as a rough guideline from industry data:
| Austenitizing Temp (°F) | Approx. Hardness (HRC) |
|---|---|
| 2050 | 60 – 61 |
| 2100 | 61 – 62 |
| 2150 | 62 – 63 |
Cryogenic treatments—such as immersing the blade in liquid nitrogen—are commonly recommended for high-vanadium tool steels like CPM S90V. This additional step helps convert any retained austenite into martensite, which can further enhance hardness, wear resistance, and edge stability.
CPM S90V is especially lauded among knife enthusiasts for the following:
Edge Retention
Corrosion Resistance
Toughness
Ease of Sharpening
When placed side-by-side with other high-performance steels, CPM S90V’s identity becomes clearer:
Versus CPM 3V
Versus AEB-L
Versus M390
Versus S30V / S35VN / S45VN
Knives fabricated from CPM S90V excel when frequent resharpening is impractical or when extended cutting sessions are the norm:
Hunting Knives
Everyday Carry (EDC)
High-End Folders and Collector Pieces
However, if extreme toughness is required for heavy batonning, prying, or repeated impacts, steels like CPM 3V or 5160 may be more suitable. Those without access to specialized sharpening equipment might also be deterred by CPM S90V’s demanding sharpening requirements.
Although CPM S90V boasts very good corrosion resistance, basic maintenance is still recommended to ensure a blade’s longevity:
Patina formation (common in high-carbon steels like 1095) is not typically associated with CPM S90V due to its chromium content. Some minor staining or “shadowing” can occur if exposed to highly corrosive substances for extended periods without cleaning.
Steels with complex, carbide-rich formulations and produced via powder metallurgy command higher prices, and CPM S90V exemplifies this trend. Knives made from CPM S90V typically appear in the premium or high-end price bracket, and the raw steel stock is likewise costly relative to standard stainless alloys. Nonetheless, many advanced knife enthusiasts and collectors deem the price justified, as the combination of excellent edge retention and high corrosion resistance frequently translates to practical value for those willing to invest in a blade that stays sharp through rigorous use.
Various knife manufacturers and custom makers have turned to CPM S90V for flagship models or special limited-edition runs. While the lineup changes over time, notable examples often include:
Benchmade 940 Series (Limited Editions)
Spyderco Paramilitary 2 (Sprint Runs)
Custom Folders
For both factory-made production blades and high-end custom pieces, CPM S90V often serves as a hallmark of premium craftsmanship and serious performance credentials.
CPM S90V stands among the elite stainless steels available to knife makers, offering an impressive suite of properties that appeal to users who require or simply desire top-tier performance. Its powder metallurgy production yields a refined microstructure with abundant, uniformly distributed carbides, resulting in:
These characteristics situate CPM S90V in a specialized niche, favoring those willing to invest both in a premium blade and in the necessary sharpening equipment. Although forging and heat-treating CPM S90V require careful attention—particularly controlling the temperature window and leveraging cryogenic treatments—the payoff is often a blade that excels in wear resistance far beyond many simpler steels.
Proper forging, quenching, and tempering can allow the steel to reach hardness values in the low to mid-60s HRC while maintaining sufficient structural integrity for demanding cutting tasks. While more affordable or more forgiving steels exist, CPM S90V continues to enjoy popularity due to the elevated performance it delivers for trained users and collectors who appreciate its demands. Its presence in high-end hunting knives, EDC folders, and collector’s pieces cements CPM S90V’s prominent place in modern knifemaking.
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