Pipe cap is welded in ends caps or mounted on the pipe end male thread to cover plugging the tube fittings. Used to seal the pipeline, the role of the same plugs. Blind plate close to the form, but the blind is removable closure, and welding pipe cap is not removed. Cap has one convex cap, cone shells, adjustable segment, flat cap and tight mouth design.

Convex caps are as follows: a hemispherical cap, oval cap, dish-shaped crown cap and ball cap. From the perspective of the force gradually bad convex caps from hemispherical cap, but the manufacturing difficulty speaking, good manufacturing slightly.

When splicing requires only allows the weld direction is radial and circumferential. After the large caps may cancel this requirement. Stitching distance should be required to be greater than 3δ, and not less than 100mm (HAZ is a high stress area, and in the chemical composition of the area will be burning, so to avoid high stress area, the region and the thickness of the relevant according to experience, the stress decay length greater than 3δ, and not less than 100mm). However, refrigeration equipment is sometimes difficult to meet this requirement, has its particularity.