High pressure thick wall pipe cap

High pressure thick wall pipe cap is an excellent important part of pressure vessel equipment in petrochemical, atomic energy, food and pharmaceutical industries. The head is the end cover on the pressure vessel and a main pressure bearing part of the pressure vessel. Its function is sealing. First, the upper and lower bottoms of the tank shaped pressure vessel are made. Second, when the pipe ends and is not ready to extend forward, a head is used to seal the pipe by welding. The products with the same function as the head are blind plate and head, but those two products can be disassembled

High pressure thick wall pipe cap is also known as elliptical head, which is a head composed of rotating elliptical spherical surface and cylindrical straight section. The elliptical head with the ratio of the long axis to the short axis of the rotating elliptical spherical bus of 2.0 is traditionally called the standard elliptical head. The mechanical properties of elliptical heads are only inferior to hemispherical heads, but superior to dished heads. As the dimensions of elliptical heads are between hemispherical heads and dished heads, the requirements for stamping equipment and molds and manufacturing difficulties are also between the two, that is, easier than hemispherical heads and more difficult than dished heads. In recent years, it is convenient to manufacture large diameter elliptical heads due to the spinning process. After resistance welding, deformation exceeding the allowable deformation will occur, which will inevitably affect the use of the head. After analysis, it is found that the cause of such problems is uneven local heating and cooling on the head structure. Generally, the closer to the weld, the higher the temperature will be, and the greater the expansion will occur

High pressure thick wall pipe caps are generally formed by stamping for standard series heads, but spinning is generally used for non-standard series heads or heads with large diameters

Generally, cold spinning is used for spinning heads of high-pressure thick wall pipe caps, but it is difficult to use cold spinning when the head is thick or the material strength is high. For heads at the edge of the capacity limit of cold spinning equipment, if cold spinning is used, problems such as material delamination and surface microcracks will occur