Stainless steel end caps, also known as elliptical end caps, dished end caps, or spherical end caps, can be classified into spherical, elliptical, dished, spherical crown, conical, and flat cap types based on their geometric shapes. Spherical, elliptical, dished, and spherical crown types are collectively referred to as convex end caps. These are industrial products used to seal the ends of stainless steel pipes, primarily in the petroleum, chemical, pharmaceutical, food, machinery, construction, nuclear power, aerospace, and pressure vessel industries. Their specifications cover diameters from Ф32mm to 6000mm and thicknesses from 1-60mm. Common materials include 304, 316L, and duplex stainless steel, conforming to national standards such as JB/T4746 and GB/T25198-2023.
These products are welded to pipes to form sealed containers. During manufacturing, thermal and structural stresses must be comprehensively addressed. Elliptical end caps consist of a rotating elliptical spherical surface and a cylindrical straight section. Their mechanical properties are second only to hemispherical end caps, combining the advantages of good stress distribution of hemispherical end caps and shallow depth of dished end caps. Production can employ molding or spinning processes, and performance is enhanced through heat treatment processes such as solution treatment and stress-relieving annealing. Temperature uniformity is crucial. Austenitic stainless steel heads can be warm-formed at 120-250°C. Some improved heads feature a stretchable and adjustable structure, cross-reinforcing blocks, and wear-resistant layers to enhance corrosion resistance, sealing, and service life, making them suitable for end closures of pressure vessels and piping systems.