The primary reason cast iron is heavy is due to its composition and the casting process used to create it.
Composition: Cast iron is made primarily of iron, along with smaller amounts of carbon, silicon, and other impurities. The high iron content gives cast iron its characteristic strength and durability. Iron is a dense metal, which means it has a high mass relative to its volume, making cast iron heavy.
Casting process: Cast iron gets its name from the casting process used to manufacture it. Molten iron is poured into molds, where it cools and solidifies, taking the shape of the mold. The molds used for casting are typically made of sand or metal. The thick and solid nature of cast iron results from this casting process, contributing to its overall weight.
Microstructure: Cast iron has a unique microstructure with graphite flakes or nodules embedded in a matrix of ferrite or pearlite. This microstructure is responsible for the material's brittle nature, but it also adds to its weight.
Due to its weight and high heat retention properties, cast iron is an excellent material for cookware, as it distributes and retains heat evenly. However, the weight can also be a downside for some people, as it can make handling cast iron cookware more challenging, especially with larger pieces like Dutch ovens or skillet pans. Nevertheless, many people appreciate the durability, versatility, and excellent cooking capabilities that cast iron offers, making it a popular choice in the kitchen despite its weight.