Spyderco’s twenty-first Mule Team installment showcases Crucible® CPM® 4V® blade steel—a powder metallurgy tool steel that offers high impact toughness and very good wear resistance. Developed for demanding industrial applications where a combination of strength, wear resistance and toughness is required, CPM 4V has significantly more carbon, vanadium, and molybdenum than CPM 3V. The result is a steel that is capable of a higher attainable hardness and even greater abrasion resistance than CPM 3V and significantly better toughness and wear resistance than D2. Despite these advanced performance qualities, CPM 4V has only 5% chromium--below the threshold of stainless steel--and therefore must be properly maintained to protect it from corrosion.

Like conventional steels, particle metallurgy steels begin with a homogenous bath of molten high-alloy steel. However, instead of being poured into ingot molds, the molten steel is forced through a nozzle under high pressure to create a spray of small spherical droplets that quickly solidify into powder particles. The small size of the particles forms micro-ingots, drastically reducing the alloy segregation in the steel and ensuring an extremely fine, uniform carbide structure. This enhances the steel’s edge retention, as well as its grinding and polishing characteristics.

CPM 4V's exact alloy composition is as follows: Carbon: 1.35%, Manganese: 0.40%, Silicon: 0.80%, Chromium: 5.0%, Molybdenum: 2.95%, Vanadium: 3.85%.