08/14/2026
What does CPM M4 mean?
CPM M4 is a type of premium tool steel commonly used for high-performance knives.
CPM = Crucible Particle Metallurgy, a manufacturing process that produces a very fine, uniform steel structure.
M4 = the specific high-carbon, high-speed tool-steel formulation.
Why is M4 popular for knives?
🔪 Excellent edge retention; one of its biggest strengths
💪 Very high wear resistance; holds an edge through a lot of cutting
⚙️ High toughness for such a hard, wear-resistant steel.
🔥 Can be heat-treated to very high hardness, often around 60–64 HRC
⚠️ Not stainless: it has relatively low chromium, so it can rust if exposed to moisture, blood, sweat, etc.
Check out our line of Extrak Fixed Blade hunting knives to see why we choose the M4 difference in blade steel.
