A conical head is a closure with a conical surface on the shell. Its features include uniformly changing the velocity of the medium as it passes through, which facilitates the complete discharge of viscous liquids and materials containing solid particles. However, it has poor mechanical properties, and the discontinuous stress generated at the junction with a cylinder or pipe due to the shape change is significant. To reduce the discontinuous stress, a flanged structure or a locally thickened structure with a curved transition can be used at either the large or small end of the conical shell. Our country's pressure vessel design specifications require that when the semi- cone angle is greater than 30°, the large end of the conical shell should be flanged; when the semi- cone angle is greater than 45°, the small end should be flanged. Due to the thicker wall of the conical head, manufacturing is not convenient, and it is only used when necessary for the process.