Steel Comparisons / K390 vs CPM S110V Knife Steel Comparison
When it comes to high-performance knife steels, two names that often spark debate among enthusiasts are Böhler-Uddeholm K390 and Crucible’s CPM-S110V. Both are prized for their advanced metallurgical properties and exceptional cutting performance. In this comprehensive guide, we’ll compare K390 and CPM-S110V across a range of practical considerations—chemical composition, heat treatment, toughness, edge retention, corrosion resistance, ease of sharpening, and more. By the end, you’ll have a clear understanding of what makes each steel stand out and how to choose the one best suited for your specific needs.
K390 is a premium powder-metallurgy tool steel developed by Böhler-Uddeholm. It is engineered to excel in wear resistance and edge retention, making it a favorite among those who push their knives to extreme cutting tasks.
K390’s high carbon content (~2.47%) and substantial vanadium (~9%) contribute significantly to its excellent edge retention and overall wear resistance. Its chromium content (~4.2%) is below the ~13% mark typically needed for stainless classification, so K390 only offers fair corrosion resistance.
Typical hardness levels for K390 range from around 60 to 64 HRC, depending on the specific heat treatment. Most knife makers opt for ~61–63 HRC to balance hardness with durability.
K390 is featured in certain Spyderco models (e.g., Delica 4, Endura 4, Police 4 in K390) and is also popular among custom knife makers who want top-tier wear resistance with decent toughness.
CPM-S110V is a high-end stainless tool steel produced by Crucible using powder metallurgy. Known for its potent combination of wear resistance and strong corrosion resistance, CPM-S110V caters to those who prioritize edge longevity in wet or corrosive environments.
With around 15.25% chromium, CPM-S110V meets the requirements for stainless steel, delivering excellent corrosion resistance. Its high carbon (~2.9%) and vanadium (~9%) contents yield very high wear resistance, though at the cost of moderate toughness.
CPM-S110V typically reaches a hardness between 60 and 63 HRC. Achieving peak hardness (around 62–63 HRC) maximizes wear resistance, though some makers might temper it slightly lower to improve toughness.
You’ll commonly see CPM-S110V in high-end production knives like Spyderco’s “Blurple” series (Paramilitary 2, Manix 2, etc.) and in custom blades where rust resistance is a priority.
K390: ~60–64 HRC
Blades at the higher end of this range offer remarkable edge stability but may be more prone to chipping if misused. Many makers settle around 61–63 HRC.
CPM-S110V: ~60–63 HRC
Hardness around or above 61 HRC results in exceptional edge retention. However, going too high can reduce toughness, so 62–63 HRC is common in premium knives.
Both K390 and CPM-S110V are powder-metallurgy steels that typically favor stock removal methods rather than traditional forging. They demand precise heat-treat protocols:
Because of their high alloy content, both steels are more susceptible to warping and cracking if the heat treatment is not tightly controlled.
K390:
Low chromium content (~4.2%) means it can form a natural patina. For many users, this patina is aesthetically pleasing and offers mild corrosion protection. If neglected, though, active rust can develop. Where desired, some makers apply coatings (DLC, Cerakote, etc.) to reduce corrosion.
CPM-S110V:
With ~15.25% chromium, it generally remains shiny and rust-free. Patina formation is nearly nonexistent. Coatings are usually not necessary beyond aesthetics.
Attribute | K390 | CPM-S110V |
---|---|---|
Corrosion Resistance | Fair (will rust without care) | Excellent (stainless) |
Toughness | Good | Fair |
Edge Retention | Excellent | Very Good |
Ease of Sharpening | Fair (slightly easier) | Fair (often more challenging) |
Typical Hardness (HRC) | ~60–64 | ~60–63 |
Patina Formation | Yes (develops patina) | No (stays bright) |
Ideal Uses | Outdoor, bushcraft, EDC | Wet/humid EDC, kitchen, folders |
Both K390 and CPM-S110V sit at the upper echelon of knife steel performance. Their high wear resistance, strong edge retention, and specialized heat-treat requirements make them staples in high-end folding knives, bushcraft blades, and premium kitchen knives.
Choose K390 if:
Choose CPM-S110V if:
Ultimately, geometry, heat treatment, and usage habits also affect how these steels perform. If you can handle the maintenance, K390’s toughness and wear resistance might appeal to you. If rust prevention and minimal upkeep are key, CPM-S110V shines.
K390 and CPM-S110V are cornerstones of the modern “super-steel” landscape. Each caters to different usage priorities—K390 excels with exceptional edge retention and decent toughness but requires more maintenance, while CPM-S110V offers robust edge-holding and industry-leading corrosion resistance. Whichever you choose, ensure it’s properly heat-treated and sharpened. Experimentation is part of the joy for knife enthusiasts: discover how each steel’s unique capabilities elevate your cutting experience.
Is K390 stainless?
No. With only about 4.2% chromium, K390 falls well below the ~13% threshold for stainless steels.
Which steel is easier to sharpen, K390 or CPM-S110V?
Both can be challenging, but many users find K390 slightly easier due to having fewer niobium carbides. High-quality diamond or ceramic abrasives are recommended for both steels.
What are some real-world knives using these steels?
How do I prevent rust on K390 blades?
Regularly clean and dry your blade, apply a light coat of oil or protective wax, and store it in a dry environment.
Which steel is better for kitchen use?
CPM-S110V generally performs better in the kitchen setting due to its excellent stainless properties, whereas K390 needs extra care around moisture and acids.
Regardless of your choice, both K390 and CPM-S110V represent the pinnacle of modern knife steel technology. By matching the steel’s strengths to your environment and cutting needs, you can find a blade that truly excels in your daily (or extreme) tasks.
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