A pipe cap is a fitting used to seal a pipeline, and it is typically fixed to the end of a pipe through welding or threaded connection.

Pipe caps are also known as plugs, end covers, pipe lids, or blind heads. They are fittings installed on the external threads at the pipe end to block the pipe. Pipe caps encompass designs such as convex pipe caps, conical shells, reducing sections, flat covers, and contracted openings. Convex pipe caps include hemispherical pipe caps, elliptical pipe caps, dished pipe caps, and spherical crown pipe caps. From the perspective of stress bearing, the performance of convex pipe caps gradually deteriorates from the hemispherical type. However, in terms of manufacturing difficulty, they become easier to produce progressively. Pipe caps and vessel heads have similar shapes, with stainless steel being a commonly used material. Pipe caps are relatively small in size and can be forged. Vessel heads, which are generally larger, are usually made by pressing steel plates. Pipe caps are generally used at the ends of pipes, while vessel heads are applied to the top and bottom (for vertical equipment) or the left and right ends (for horizontal equipment) of container vessels.