Flat heads, also known as flat-bottomed heads, are classified by shape into: flat-bottomed perforated heads, flat-bottomed tube sheet heads, and folded flat heads. Flat-bottomed heads (flat heads) are often used in large pressure vessels and pressure pipelines. 　　The application scope of flat heads: petroleum, electronics, chemical engineering, medicine, light textile, food, machinery, construction, nuclear power, aerospace, military industry and other industries.