三通的分類Classification of three links
按管徑尺寸劃分
等徑三通的接管端部均為相同的尺寸；
異徑的三通的主管接管尺寸相同，而支管的接管尺寸小于主管的接管尺寸。
按工藝劃分
1. 液壓脹形
三通的液壓脹形是通過金屬材料的軸向補償脹出支管的一種成形工藝。其過程是采用專用液壓機，將與三通直徑相等的管坯內注入液體，通過液壓機的兩個水平側缸同步對中運動擠壓管坯，管坯受擠壓后體積變小，管坯內的液體隨管坯體積變小而壓力升高，當達到三通支管脹出所需要的壓力時，金屬材料在側缸和管坯內液體壓力的雙重作用下沿模具內腔流動而脹出支管。
三通的液壓脹形工藝可一次成形，生產效率較高；三通的主管及肩部壁厚均有增加。
因無縫三通的液壓脹形工藝所需的設備噸位較大，目前國內主要用于小于DN400的標準壁厚三通的制造。其適用的成形材料為冷作硬化傾向相對較低的低碳鋼、低合金鋼、不銹鋼，包括一些有色金屬材料，如銅、鋁、鈦等。
2. 熱壓成形
三通熱壓成形是將大于三通直徑的管坯，壓扁約至三通直徑的尺寸，
冷拔三通
冷拔三通
在拉伸支管的部位開一個孔；管坯經加熱，放入成形模中，并在管坯內裝入拉伸支管的沖模；在壓力的作用下管坯被徑向壓縮，在徑向壓縮的過程中金屬向支管方向流動并在沖模的拉伸下形成支管。整個過程是通過管坯的徑向壓縮和支管部位的拉伸過程而成形。與液壓脹形三通不同的是，熱壓三通支管的金屬是由管坯的徑向運動進行補償的，所以也稱為徑向補償工藝。
由于采用加熱后壓制三通，材料成形所需要的設備噸位降低。熱壓三通對材料的適應性較寬，適用于低碳鋼、合金鋼、不銹鋼的材料；特別是大直徑和管壁偏厚的三通，通常采用這種成形工藝。
以材質劃分
碳鋼，鑄鋼，合金鋼，不銹鋼，銅，鋁合金，塑料，氬硌瀝，pvc等。
以制作方法劃分
頂制、壓制、鍛制、鑄造等。
以制造標準劃分
國標、電標、化標、水標、美標、德標、日標、俄標等，具體如下：GB/T12459-2005,GB/T13401-2005,ASME B16.9,SH3408,SH3409-96,SH3410-96,HG/T21635,DL/T 695,SY/T 0510,DIN 2615。
Partition according to diameter
The ends of the connecting ends of equal diameter three links are all of the same size.
The diameter of the three way main pipe takes the same size, and the size of the branch pipe nozzle is smaller than the nozzle size of the main pipe.
According to process division
1. hydraulic bulging
The three way hydraulic bulging is a forming process that expands the branch pipe by axial compensation of metal material. The process is to use a special hydraulic press to inject liquid into the pipe billet equal to the three pass diameter. Through the two horizontal cylinders of the hydraulic press, the tube blank is extruded synchronously, the volume becomes smaller after the extrusion of the tube, and the pressure of the liquid in the tube billet increases with the volume of the tube, when the pressure is needed to reach the three pipe. Under the action of the liquid pressure in the side cylinder and the tube blank, the metal material flows along the inner cavity of the die and expands the branch pipe.
The three way hydraulic bulging process can be formed at one time, and the production efficiency is higher. The head and shoulder wall thickness of the three links increase.
Because of the large tonnage of the hydraulic bulging process with seamless three links, the current domestic manufacture is mainly used for the standard wall thickness of less than DN400 three links. The suitable forming materials are low carbon steel, low alloy steel and stainless steel, which have relatively low cold hardening tendency, including some nonferrous metal materials, such as copper, aluminum, titanium and so on.
2. hot pressing forming
The three way hot pressing is to flatten the tube blank with a diameter greater than three diameters to about three diameters.
Cold - drawn three - way
Cold - drawn three - way
A hole is opened in the part of the drawing branch; the tube is heated to be put into the forming die and loaded into the die in the tube blank; the tube is compressed in radial direction under the action of pressure, and the metal flows into the direction of the branch pipe during the radial compression and forms a branch under the tension of the die. The whole process is formed by the radial compression of the billet and the drawing process of the branch. Unlike the hydraulic bulging three way, the metal of the hot pressing three way branch pipe is compensated by the radial movement of the tube blank, so it is also called the radial compensation process.
Due to the use of heating to suppress three passes, the equipment tonnage required for material forming is reduced. The three - pass hot press is suitable for the material with wide adaptability to low carbon steel, alloy steel and stainless steel, especially for the three through thick diameter and tube wall, which is usually used in this forming process.
Material division
Carbon steel, cast steel, alloy steel, stainless steel, copper, aluminum alloy, plastic, argon leaching, PVC and so on.
Dividing by making methods
Top making, pressing, forging, casting, etc.
Dividing by manufacturing standards
The national standard, the electric standard, the standard, the water mark, the American Standard, the German standard, the Japanese standard, the Russian standard and so on, as follows: GB/T12459-2005, GB/T13401-2005, ASME B16.9, SH3408, SH3409-96, SH3410-96, HG/T21635, DL/T 695, SY/T 0510, DIN 2615.
