Cast iron usually refers to grey cast iron, but can mean any of a group of iron-based alloys containing more than 2% carbon. It is made by remelting pig iron, often along with substantial quantities of scrap iron and scrap steel, and taking various steps to remove undesirable contaminants such as phosphorus and sulfur, which weaken the material. Carbon and silicon content are reduced to the desired levels, which may be anywhere from 2% to 3.5% for carbon and 1% to 3% for silicon depending on the application. Other elements are then added to the melt before the final form is produced by casting.

The result of this process, is a strong, durable product that will last for many years to come.