Introduction In the world of knives, steel is an essential material that defines the performance, durability, and versatility of the tool. Various types of high-end steel have been developed to serve specific purposes in knife-making, and among them, CPM M4 is a highly-regarded choice for many professionals and enthusiasts. This article aims to explore the properties of CPM M4, its metallurgical composition, and its history to understand why it is attracting attention in the world of knives. Composition of CPM M4 CPM M4 is a high-performance, high-speed tool steel developed by Crucible Industries. It is known for its excellent wear resistance, high toughness, and impressive edge retention capabilities. The acronym "CPM" stands for Crucible Particle Metallurgy - a patented process in which steel is made from powder metallurgy, resulting in a steel with a very homogeneous structure. The alloy's composition plays a significant role in defining the steel's properties and is crucial in determining how well it will perform as a blade. The following composition percentages of CPM M4 provide a basic understanding of how these elements contribute to the steel's overall performance: 1. Carbon: 1.40% 2. Chromium: 4.00% 3. Manganese: 0.30% 4. Molybdenum: 5.25% 5. Silicon: 0.55% 6. Sulfur: 0.06% 7. Tungsten: 5.50% 8. Vanadium: 4.00% The relatively high carbon content adds to the steel's hardness, while the presence of chromium and molybdenum contributes to its wear resistance and toughness. Tungsten and vanadium, along with carbon and chromium, are essential for the formation of hard carbides within the steel, providing improved wear resistance and edge retention. Additional trace elements, such as manganese and silicon, work to strengthen the steel while sulfur plays a role in improving machinability. CPM M4 Steel History CPM M4 dates back to the late 20th century when it was initially developed for industrial cutting and metalworking applications primarily due to its wear resistance and capability to hold a sharp edge in demanding conditions. Crucible Industries, an American company with a long history of producing specialty steels, recognized the potential of this alloy and adapted it for knife-making purposes. Following its entry into the market as a top-tier knife steel, CPM M4 has been the material of choice for various types of knives including folding knives, fixed blades, and even custom creations. The steel's popularity has soared among professional knife users such as chefs, as well as collectors and outdoor enthusiasts. Its excellent performance characteristics have made CPM M4 a staple in the premium knife market. Conclusion CPM M4 is an exemplary option for knife steel, offering a combination of impressive properties that allow users to experience the best in edge retention, wear resistance, and toughness. Its unique and balanced composition provides this steel with an unyielding performance that has garnered praise from professionals and enthusiasts alike. As the demand for high-quality knife steel continues to grow, the reputation and utilization of CPM M4 steel will likely continue to expand and solidify its place in the world of knives.