H-13 is a high-speed steel alloy used as a cutting tool material in metalworking. It is often referred to as a "super steel" because of its superior metalworking properties, and is used for making a wide range of precision tools, including reamers, drills, taps, milling cutters and countersinks. H-13 is composed of chromium, molybdenum, vanadium, and tungsten, with a small amount of carbon, making it a difficult material to work with. The composition gives H-13 excellent hardness and heat-resistance, as well as good machinability and toughness while working.