89How to distinguish between caps and heads?

89How to distinguish between caps and heads?  

The use of pipe cap and head is the same, but the head generally refers to the GB/25198-2010 standard, while in the customer's welding pipe fitting standard GB/T12459-2017, there is no mention of the head, only the word with pipe cap, which is in GB/T12459-2017.  Even in GB/T13401-2017, it is also marked by a tube cap.  There is no mention of the head, that is to say in the steel butt welded seamless pipe fitting standard inside said is the pipe cap.  Specifications are all small, large GB/T12459-2017 outer diameter φ 813 and φ 820 specifications.  That is to say, the larger GB/T13401-2017 standard in the large cap is also φ 1220 of the product.  If you want to find a larger head, you have to make it according to customer requirements and manufacturing standards, which can be φ 6000, that is, the diameter of DN6000 products.  The data for various headers in the standard is also very clear.  For example, the inner diameter of the oval head is the reference head, and the outer diameter of the pipe cap is the reference head, or the spherical head, the disc head, the spherical crown head, the cone shell head and the bottom head are written in very detail.  

 Pipe cap, also known as plug, cap, etc., is welded at the pipe end or installed on the pipe end of the external thread to cover the pipe fittings, used to close the pipeline.  The official cap diameter is generally less than DN300, mainly used in the pipeline, and the pipeline butt or as a block plate to strengthen the role, not as the main compression element.  The common material of pipe cap is carbon steel :(20#, A3, Q235A, Q235B, 20G, 16Mn, ASTM A234WPB, ASTM A105, etc.);  Stainless steel :(304, 304L, 316, 316L, S30408, S30403, S31608, S31603, SUS304, ASTM  A403, TP321, 0Cr18Ni9, 00Cr19Ni10, 00Cr17Ni14Mo2, 1Cr18Ni9Ti, 06Cr17Ni12Mo2, 022Cr17Ni12Mo2 etc.)  Pipe cap diameter :DN15-DN800 Wall thickness :SCH10-SCH160 Standard :ASMEB16.9, GB/T12459-2017, etc.  

 The head is the end cover of the pressure vessel, which is a main bearing part of the pressure vessel.  Its role is to seal.  One is to make the upper and lower bottom of the can-shaped pressure vessel, and the other is that the pipe is at the end and is not ready to extend forward, so a head is used to seal the pipe in the form of welding.  According to the different geometric shape, it can be divided into spherical, oval, disc, spherical crown, cone shell and cap, among which spherical, oval, disc and spherical crown head are collectively referred to as convex head.  Used in all kinds of container equipment, such as tanks, heat exchangers, towers, reactors, boilers and separation equipment, etc.