Gray iron is a type of cast iron known for its high carbon content, which gives it a gray appearance when fractured. It is widely used in various applications due to its excellent castability, machinability, and wear resistance. Common uses include engine blocks, pipes, and machine bases. The structure of gray iron consists of graphite flakes, which contribute to its strength and ability to absorb vibrations. This material is often favored in construction and manufacturing because it can withstand high temperatures and is relatively inexpensive to produce compared to other metals like steel or aluminum.