What is Cast Iron?
Cast iron has become a synonym for durability — a cast iron stomach, a cast iron alibi. As metals go, however, it is actually something of a Brunswick stew. While the pig iron that forms the basis for cast iron is being melted, scrap iron and steel are often thrown into the mix. When the process is complete and impurities such as sulfur are subtracted, the end product is actually only 95 percent iron. The rest of the chemical makeup is primarily carbon and silicon, in various percentages. Anything over two percent silicon is known as “gray cast iron,” while a lesser amount gives birth to “white cast iron.” White cast iron is not actually white, but gets its name from a reaction with the increased carbon that creates small white deposits of cementite on an otherwise dark surface. Despite its metaphorical reputation, cast iron is more brittle than pure iron and steel, and melts at a lower temperature. This is not a bad thing as far as industrial applications are concerned, because it ma
Cast iron is an alloy with a high carbon content (at least 1.7% and usually 3.0 to 3.7%) that makes it more resistant to corrosion than either wrought iron or steel. In addition to carbon, cast iron contains varying amounts of silicon, sulfur, manganese, and phosphorus. While molten, cast iron is easily poured into molds, making it possible to create nearly unlimited decorative and structural forms. Unlike wrought iron and steel, cast iron is too hard and brittle to be shaped by hammering, rolling, or pressing. However, because it is more rigid and more resistant to buckling than other forms of iron, it can withstand great compression loads. Cast iron is relatively weak in tension, however and fails under tensile loading with little prior warning. The characteristics of various types of cast iron are determined by their composition and the techniques used in melting, casting, and heat treatment. Metallurgical constituents of cast iron that affect its brittleness, toughness, and strengt
An alloy of iron containing so much carbon that it is brittle and so cannot be wrought but must be shaped by casting. Cast Iron is a hard, brittle, nonmalleable iron-carbon alloy, cast into shape, containing 2 to 4.5 % carbon, 0.5 to 3 % silicon, and lesser amounts of sulfur, manganese, and phosphorus. Basically, cast iron solidifies into a heterogeneous alloy with a metallurgic structure composed of more than one constituent. Apart from iron the basic elements of its chemical composition are carbon and silicon.
