Investment casting with carbon steel is the choice for many manufacturers of a wide range of parts and components due to its versatility and variety of properties. As its name clearly states, it combines steel and carbon, plus other components. The amount of carbon determines the type of carbon steel. As the amount of carbon is increased, it becomes hard, more brittle and less ductile. According to the American Iron and Steel Institute (AISI), it can contain up to 2.1% of carbon by weigh. It can also include copper, manganese, silicon, chromium, cobalt, molybdenum, nickel, niobium, titanium, tungsten, vanadium, zirconium and other elements. Low carbon steel is often used for bolt, fasteners and similar parts. Higher carbon steels go into shafts, axles, tools, engines and other applications.