The head is a circular or semicircular component used to seal the container, usually made of metal. Its main forms include flat bottoms, hemispherical head, elliptical head and torispherical head. Each form has its specific application field and advantages.

Flat bottom is the most common head form, which consists of a flat surface and a curved edge, and is suitable for general pressure vessels. Hemispherical head has good force performance and uniform stress distribution, and is widely used in high-pressure vessels and chemical equipment. Elliptical head is suitable for narrow and long containers, which can reduce fluid resistance and pressure loss. Torispherical head consists of half spherical surface and half conical surface, and is suitable for bottom head.