There are many different types of steel that your knife could be made from. Why choose CPM 3V Steel? Toughness. CPM 3V steel has its advantages when it is used in a knife. It makes a great field knife blade that is tough and unlikely to break with heavy, near abusive, use. It will likely oxidize over time depending on the working environment, 3V steel is not stainless. Different types of steel have different properties, and some are better for knives than others. There are four general properties which most use to evaluate knife steel:
Edge Retention/Wear Resistance (how the cutting edge holds up to cutting use)
Toughness (how durable the blade is)
Heat treatment (The hardness of the steel)
Corrosion resistance (Amount of chromium in the composition of the steel, chromium content over 11% is considered stainless)
What does CPM stand for? Crucible Particle Metallurgy (CPM)
CPM steel utilizes and expensive and complex manufacturing process that provides a more even distribution of carbides. CPM 3V is an American-made steel product by Crucible Industries in Syracuse, New York. CPM is a trademarked name for a process that is also called Powdered Metallurgy or PM steel. CPM, makes the steel stronger than the SAME steel made using a conventional steel manufacturing process. CPM makes the steel more resistant to breaking, fracturing or chipping.
Carbide Distribution in CPM Steel vs Conventional Steel (Courtesy of Crucible Industries.)
CPM 3V steel has the following steel composition (Note the high amount of vanadium content which produces some of the smallest and hardness carbides in knife steel.)
CPM 3V Toughness & Wear Resistance vs D2, A2 & CPM M4 (Courtesy of Crucible Industries.)
Let us discuss CPM 3V steel when it comes to its performance in a knife. Again, consider the four properties of knife steel:
Toughness - This steel has outstanding toughness, so you can expect it to survive abuse in the field and in survival scenarios. This is the principle reason to select CPM 3V for a knife.
Edge Retention/Wear Resistance - CPM 3V steel does not hold its edge as well as some other steels like S35VN or S30V. This means that the combination of alloys in the steel make it more susceptible to dulling with repeated use. That being said, according to Crucible's testing it holds an edge better than D2 (which is a comparable tool steel used in knifemaking) at a hardness 60 RC. When comparing CPM 3V steel vs. A2 steel, 3V is superior in edge retention and toughness with a big win for CPM 3V.
Heat Treatment - Heat treatment effects the edge retention and toughness and is determined by the knifemaker. According to Crucible, 3V steel is meant to be heat treated in 58-60 RC (Rockwell Hardness Measurement) range for knife blades. Less hardness in the heat treatment will mean more toughness but less edge retention; like many properties with knife steel it is a trade-off in qualities.
Corrosion Resistance - CPM 3V steel is not stainless steel, it will oxidize if not properly cared for. Even with proper care, discoloration or oxidation can be expected over time. Applying a very hard, scratch resistant coating such as PVD or DLC to a blade surface will help slow corrosion where the coating covers the blade - which general excludes the cutting edge.
I hope this article has been informative about the CPM 3V Steel, one of the toughest blade steels available for use on knives.