dished head

Butterfly shaped head is an end cap on pressure vessels and is a major pressure bearing component of pressure vessels. Its function is sealing. One is to make the top and bottom of the pressure vessel body, and the other is to seal the pipe by welding it with a head when it reaches the end and no longer intends to extend forward. Products that have similar functions as head seals include blind plates and pipe caps. Blind plates and threaded pipe caps can be disassembled. After the head is welded, it cannot be disassembled again. The quality of the head is directly related to the long-term performance and good operation of the pressure vessel. According to different geometric shapes, heads can be divided into several types such as spherical, elliptical, disc-shaped, spherical crown shaped, conical shell, and flat cap. Among them, spherical, elliptical, disc-shaped, and spherical crown shaped heads are also collectively referred to as convex heads. In welding, it is divided into butt welding heads and socket welding heads

The head is divided into carbon steel, stainless steel, alloy steel, special alloy steel, duplex stainless steel, etc. according to the manufacturing material; Carbon steel: (20 #, A3, Q235, Q23 excellent, Q235B, 20G, Q245R, Q345, Q345R, 16Mn, ASTM A234WPB, ASTM A105, etc.); Stainless steel: (304, 304L, 316, 316L, S30408, S30403, S31608, S31603, SUS304, ASTM A403, TP321, TP317L, 347, 0Cr18Ni9, 00Cr19Ni10, 00Cr17Ni14Mo2, 1Cr18Ni9Ti, 06Cr17Ni12Mo2, 022Cr17Ni12Mo2, etc.); Alloy steel: (16MnR, Cr5Mo, 12Cr1MoV, 10CrMo910, 15CrMo, 12Cr2Mo1, A335P22, St45.8/III, A10bB, etc.); Special alloy steel: (TP310S, 904L, Incoloy800, Incoloy825, Incoloy600, Incoloy625, etc.); Dual phase stainless steel: (F51, S31803, S2205, F53, 2507, S32750, F55, 2607, S32760, etc.)

The commonly used names and type codes for heads are as follows:

1. Hemispherical heads: Type code: HHA;

2. Elliptical head: Type code: EHA, EHB

3. Dish shaped head: Type code: THA, THB

4. Spherical head: Type code: SDH

5. Flat bottomed head: Type code: FHA

6. Conical head: Type codes: CHA (30), CHA (45), CHA (60)

Common execution standards for heads: GB/T25198-2010 Pressure vessel heads

Head national standards, pipe fittings and pipeline standards: GB/T12459-2017, GB/T13401-2017

Head petrochemical standards: SH/T3408-2012, SH/T3409-1996

Butterfly heads are excellent and important components of pressure vessel equipment in many industries such as petrochemicals, nuclear energy, water conservancy, food, machinery, diagnostic and treatment equipment, fertilizers, shipbuilding, etc.

. Applied to various container equipment, such as storage tanks, heat exchangers, towers, reactors, boilers, and separation equipment