Tungsten steel is a type of metal alloy made from a combination of tungsten and iron. The addition of tungsten to the alloy gives it increased hardness and resistance to heat, allowing equipment made from tungsten steel to maintain high performance and to resist wear at high temperatures. Tungsten steel is valued for its industrial uses as a tool steel and is commonly used in industrial tools and machinery used for working other metals, such as dies and cutting tools.
The chemical element tungsten is a transition metal with the atomic number 74. It is also sometimes referred to as wolfram and has the chemical symbol W for that reason. Tungsten is one of the densest and most heat-resistant chemical elements in existence. It melts at a temperature of 6192°F (3422°C), giving it the second highest melting point of any chemical element and the highest of any pure, non-alloyed metal. Its density, 19.25 grams per cubic centimeter, is higher than that of uranium, lead, and the majority of the transuranic elements. Tungsten's tensile strength is also very high.
Due to its hardness and heat resistance, tungsten is a common alloying element in high speed steels, a type of tool steel. These are tool steel alloys that maintain high hardness at high temperatures, allowing them to withstand the heat and abrasion suffered by high-speed cutting tools and drills. Their tungsten content varies by alloy, but can be as high as 18.75 percent. These steels also contain carbon, and several percentage points of their composition often consists of other alloying metals such as molybdenum, chromium, and vanadium. Small amounts of additional elements such as copper, nickel, and phosphorus are also used.
High speed tungsten steel is commonly used to make machinery such as saw blades, taps, and drill bits. Due to its resistance to abrasion, it is also sometimes used in hand tools. These include chisels, files, and kitchen knives.
Tungsten is also the primary alloying element in some types of hot work tool steel, a form of tool steel used in tools that must be able to withstand extended exposure to high temperatures. In addition, hot work tool steel must be highly resistant to stress caused by rapid changes in temperature, called thermal shock. Hot work tungsten steel usually also has a high chromium content and may contain vanadium as well. It is used in equipment that works with other heated metals, such as extrusion and forging dies.
