A brief history of powder metallurgy (PM) reveals a fascinating process encompassing various methods for creating materials or components from metal powders. This innovative technique allows for the production of unique materials, which can't be achieved through traditional melting or forming methods. Powder metallurgy techniques typically involve compressing metal powder and heating it below the melting point, effectively binding the particles together. The common 'press and sinter' process consists of three essential steps: powder blending (or pulverization), die compaction, and sintering. Sintering occurs by heating the powdered metals and alloys just below their melting points, permitting an atomic restructuring that results in super steels, which are stronger and more durable than those made through historical forging methods. The compaction of powder in the die is usually done at room temperature, while sintering takes place under atmospheric pressure with a carefully controlled atmosphere. To achieve special properties or enhanced precision for tactical and outdoor gear, secondary processes like coining or heat treatment often follow. The metal powder is typically iron, mixed with additives such as lubricant wax, carbon, copper, and/or nickel, allowing for precise parts that are close to die dimensions, although they exhibit some porosity and thus sub-wrought steel properties. Currently, around 1 Mt/y of structural components made from iron-based alloys are produced using this method. Interestingly, the ancient Incas were known to create jewelry and artifacts from precious metal powders, but mass manufacturing of PM products only began in the mid to late 19th century.
Crucible Industries, widely recognized as Crucible, was an American company that specialized in developing and manufacturing high-performance steels, including a line of sintered steels known as Crucible Particle Metallurgy (CPM) steels. This company produced high-speed, stainless, and tool steels for various industries, including automotive, cutlery, aerospace, and machine tools. With a history spanning over a century, Crucible inherited its capability to produce high-grade steel from its English roots in the late 1800s. In 1900, thirteen crucible-steel companies merged, creating the largest producer of crucible steel in the United States, eventually evolving into a corporation with 1,400 employees across several states. However, the company's fortunes declined alongside the automotive industry in the 1980s, though it managed to recover in the following decade. By 2009, only 550 employees remained, and the company ultimately ceased operations in 2025, marking a poignant end to a long-standing legacy of American steel giants. This legacy has provided a wealth of high-quality steel for designing and forging strong, sharp tool steel, catering to knife designers, makers, and enthusiasts, particularly in the realm of fixed blade and tactical knives.
Most of the general public may not have knowingly interacted with CPM metals due to their predominant use in industrial applications that demand superior strength, sharpness, and longevity. The perfect blend of elite design with remarkable hardness and durability makes CPM steels a popular choice for higher-end knives. Currently, EL-MAX and Magnacut are two of the most sought-after CPM options in production. Notably, Microtech supports EL-MAX, featured in the Halo VI single-action OTF, while brands like Benchmade and Rick Hinderer utilize Magnacut steel in many of their tactical knives. Spyderco often opts for CPM-S30V and CPM-S35VN, striking a balance between hardness and corrosion resistance. The average forging temperature for quality stainless and carbon steel ranges from 2,000 to 2,250 degrees Fahrenheit, highlighting the impressive capability to forge super hard steel without the need for extensive protective gear, even more than a century after its introduction. So, to all fans of a well-crafted pocketknife and tactical gear, we owe a debt of gratitude to Crucible for their contributions!