Header Encyclopedia

The head is a component of the container, which connects the cylinder by welding. According to the different geometrical shapes, it can be divided into spherical, elliptical, dish, spherical crown, conical shell and flat cover. Among them, spherical, elliptical, dish and spherical crown heads are also called convex heads. Welding is divided into butt welding head and socket welding head. Used for various container equipment, such as storage tanks, heat exchangers, towers, reaction kettles, boilers and separation equipment. Materials include carbon steel (A3, 20, Q235, Q345B, 16Mn, etc.), stainless steel (304, 321, 304L, 316, 316L, etc.), alloy steel (15Mo3 15CrMoV 35CrMoV 45CrMo), aluminum, titanium, copper, nickel and nickel alloys, etc.
purpose
Head is an indispensable and important part of pressure vessel equipment in petrochemical, atomic energy, food and pharmaceutical industries.
Head is the end cover of pressure vessel, and it is a main bearing component of pressure vessel. The function is to seal. The first is to make the top and bottom of the tank pressure vessel. The second is that the pipe ends and is not ready to extend further. Then the pipe is sealed with a head in the form of welding. There are blinds and caps for products similar to the head, but they can be disassembled. After the head is welded, it can not be disassembled again. The matching pipe fittings are pressure vessel, pipe, flange, elbow, tee, four-way and other products.
The quality of the head is directly related to the long-term safe and reliable operation of pressure vessels.
Basic Requirements
The current head standards in our country are formulated separately according to different structural types (ellipse, dish, cone), forming methods (stamping, spinning). This not only results in unreasonable quality requirements of different standard heads, but also brings some difficulties to the selection of standard heads and the revision of standards. Hard.
First, the previous header standards are only matched with GB150 Steel Pressure Vessel, that is, only considering the requirements of manufacture, inspection and acceptance of the header designed according to the rules, while our country has completed the double-track system of GB150 and JB4732 as early as 1995 (with the Standard for Analysis and Design of Steel Pressure Vessels). Lack of head standard matching with analysis and design is a major defect of pressure vessel standardization in China.
Secondly, GB150 is a mandatory standard, but the header standard compiled according to GB150 and matched with it is recommended. This is obviously unreasonable, and it is difficult to guarantee the quality of the header, an important compressed component.