The plug is also called a head, a pipe cap, a cap, a pipe cover, and a bulkhead. It is a pipe fitting that is welded to the pipe end or installed on the external thread of the pipe end to cover the pipe. Used to seal pipelines and has the same function as pipe plugs. The form of the blind plate is similar, except that the blind plate is a removable plug, while the welding plug is not removable. The plug includes the design of convex plug, cone shell, reducing section, flat cover and tightening port.
Convex plugs include: hemispherical plugs, oval plugs, dish-shaped plugs and spherical cap-shaped plugs. From the perspective of stress, convex plugs gradually become worse than hemispheric plugs, but from the perspective of manufacturing difficulty, they are gradually easier to manufacture.