Stainless steel caps, also known as plugs or end caps, are pipe fittings welded to or installed on the external threads of pipe ends to seal the pipe. The main materials include 304, 304L, 316, 316L, 321, 2520, 310, and 317 stainless steel. The nominal diameter ranges from DN15 to DN1200, and the wall thickness covers SCH5 to SCH160. Connection methods include butt welding, socket welding, press-fit, ring pressing, ferrule, threaded, and grooved connections.
Cap designs include convex caps, conical shells, reducing sections, flat caps, and contracting ends. Convex caps include hemispherical, elliptical, and dished structures. Manufacturing follows standards such as ASME B16.9, DIN 2617, GB/T12459, and NORSOK M650, involving processes such as stamping, welding, and heat treatment, requiring non-destructive testing and deformation control. Widely used in petrochemical, nuclear power, machinery manufacturing, medical equipment, food and pharmaceutical, water and beverage, beer, food, fertilizer, shipbuilding, pipeline and other fields, for sealing pipelines and withstanding pressure.