castiron

Cast iron is an iron-carbon alloy with a carbon content typically between 2% and 4% and silicon content around 1% or more, sometimes alloyed with small amounts of sulfur, phosphorus, and other elements. It is distinguished from steel by its higher carbon content, which gives it distinct microstructures and properties. Cast iron is designed for casting and has good fluidity and excellent compressive strength, but is relatively brittle and less suitable for high-tension applications. It also offers high wear resistance and good heat retention, and its graphite-rich microstructure influences machinability and damping.

Types of cast iron include gray iron, white iron, ductile iron, and malleable iron. Gray iron contains graphite flakes, which improve machinability and damping but reduce strength. White iron has cementite and is very hard and brittle. Ductile (nodular) iron contains graphite in a nodular form, improving ductility and impact resistance. Malleable iron is a heat-treated form of white iron with clusters of irregular graphite, yielding greater ductility.

Production and processing involve smelting iron ore in a blast furnace or cupola furnace to produce molten iron, which is then poured into sand, ceramic, or investment molds. Cooling yields the characteristic microstructures. Recycled scrap iron is commonly used to reduce cost and emissions.

Applications of cast iron are broad, including engine blocks, pipes, machine bases, and other heavy machinery components. Cast iron cookware is popular for its heat retention and durability and is often seasoned to develop a nonstick patina.

Historically, cast iron production dates to ancient China, with later adoption in Europe and widespread use from the 18th century onward.