CPM S35VN is a powdered stainless steel introduced around 2009 by Crucible Industries, evolving from the well-known CPM S30V. Developed in collaboration with noted knifemaker Chris Reeve, CPM S35VN quickly became a favorite among knife enthusiasts and makers for its balanced combination of properties:
Today, CPM S35VN occupies a formidable position in the industry, appearing in premium folding knives, fixed-blade hunting tools, and more specialized designs. Despite the continuous stream of new steels entering the market, CPM S35VN has demonstrated lasting popularity thanks to its predictable heat-treat responses, refined grain structure, and exceptional all-around performance.
Building on CPM S30V’s success, Crucible introduced CPM S35VN with a slight but meaningful tweak to the alloy composition—most notably the addition of niobium. The goal was to improve toughness and machinability without sacrificing the hardness and wear resistance that made CPM S30V so popular. Early adopters quickly recognized that CPM S35VN delivered on its promise: less chipping, easier grinding, and generally smoother production runs.
Within just a few years of its release, CPM S35VN appeared in numerous production and custom knife models. Its stable performance across diverse cutting tasks and reliable heat-treating profile has anchored its reputation. Even with the rise of newer “super steels,” CPM S35VN remains prevalent among high-end knife brands and boutique makers alike.
CPM S35VN is manufactured using Crucible Particle Metallurgy (CPM), where molten steel is atomized into fine powder, then consolidated into billets. This process promotes an even distribution of carbides and a uniform grain structure.
A typical CPM S35VN composition includes:
The addition of niobium—absent in CPM S30V—contributes to finer, more uniformly distributed carbide formations. This refinement boosts edge stability, toughness, and overall consistency in heat treatment results.
CPM S35VN is most commonly shaped via stock removal methods (e.g., CNC machining, belt grinding), but some custom makers may still choose to forge it. Due to its high alloy content and wear resistance, forging requires careful thermal management:
Key risks during forging include warping or cracking if the steel’s temperature drops too low or if cross-sectional changes are made too abruptly. Slower, uniform heating and controlled cooling are crucial to preserving the steel’s fine grain structure prior to hardening.
Note: Many knifemakers prefer stock-removal techniques for CPM S35VN to reduce the complexities of forging this high-alloy steel.
One of CPM S35VN’s notable strengths lies in its adaptable heat-treatment window. It can be hardened to a range of ~58–62 HRC, though many commercial blades aim for 58–60 HRC to balance edge retention with toughness.
After heavy grinding or forging, a stress-relief cycle at about 1600 °F (871 °C) for a short soak—followed by a slow cooldown—helps reduce internal stresses before final hardening.
Typical austenitizing temperatures fall between 1900 °F (1038 °C) and 2050 °F (1121 °C). Many makers choose oil quenching or plate quenching with forced air to minimize distortion, especially in thinner blades. Cooling must be rapid enough to bypass the nose of the time-temperature-transformation (TTT) curve, preventing formation of unwanted softer phases.
Some knifemakers incorporate a cryogenic soak (e.g., liquid nitrogen or dry ice bath) after the initial quench to further reduce retained austenite, which can enhance hardness and dimensional stability.
CPM S35VN is commonly tempered twice for two hours each. Makers often choose:
Multiple temper cycles help convert any retained austenite and stabilize the final microstructure.
| Austenitizing Temperature (°F) | Approx. Hardness (HRC) |
|---|---|
| 1900 | 58–59 |
| 1950 | 59–60 |
| 2000 | 60–61 |
| 2050 | 61–62 |
Most users find ~59–60 HRC the “sweet spot,” offering a reliable balance of hardness, toughness, and corrosion resistance.
CPM S35VN is prized for its all-around robustness:
For many users, CPM S35VN’s draw is its balanced combination of stainlessness, tough-but-not-brittle hardness, and manageable upkeep.
Select uses for CPM S35VN include:
Limitations arise in specialized contexts—extreme wear resistance might be better served by steels like S90V, and maximum toughness might point toward something like CPM 3V. However, for a broad spectrum of tasks, CPM S35VN excels as an all-rounder.
While CPM S35VN’s corrosion resistance is excellent, it still contains sufficient carbon to rust if neglected. Simple maintenance routines help preserve the blade:
Unlike some tool steels, CPM S35VN seldom forms a patina, so the polished or satin finish is relatively easy to maintain.
CPM S35VN typically occupies an upper-mid-range price bracket. It is more expensive than standard stainless options like 8Cr13MoV or AUS-8 but often cheaper than or comparable to higher-alloy “super steels” like M390 or S90V. Many knifemakers consider it a stellar value given its excellent performance-versus-effort ratio in both manufacturing and final use.
Over the past decade, CPM S35VN has topped the list for numerous knife lines:
Its prevalence across custom and production segments alike testifies to the steel’s well-rounded attributes.
CPM S35VN exemplifies a carefully engineered evolution in stainless knife steels. By optimizing the chemistry of CPM S30V (notably adding niobium), Crucible created a steel with excellent corrosion resistance, good toughness, impressive edge retention, and relative ease of sharpening—all at a hardness range amenable to various uses.
Knifemakers appreciate its consistent heat-treating responses and machinability, while end-users value the dependable performance. Whether in bushcraft, hunting, or everyday carry applications, CPM S35VN stands out for its reliable blend of properties. Although specialized steels may surpass it in niche categories, few can match CPM S35VN’s synergy of corrosion resistance, toughness, and ease of maintenance.
Its continued popularity reaffirms that in the realms of metallurgy and knife making, the best steels often thrive on versatility. CPM S35VN has established—and maintained—its reputation as a meticulously balanced steel, ready to meet modern demands with proven reliability and a strong value proposition.
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