三通的分类Classification of three links
按管径尺寸划分
等径三通的接管端部均为相同的尺寸；
异径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。
按工艺划分
1. 液压胀形
三通的液压胀形是通过金属材料的轴向补偿胀出支管的一种成形工艺。其过程是采用专用液压机，将与三通直径相等的管坯内注入液体，通过液压机的两个水平侧缸同步对中运动挤压管坯，管坯受挤压后体积变小，管坯内的液体随管坯体积变小而压力升高，当达到三通支管胀出所需要的压力时，金属材料在侧缸和管坯内液体压力的双重作用下沿模具内腔流动而胀出支管。
三通的液压胀形工艺可一次成形，生产效率较高；三通的主管及肩部壁厚均有增加。
因无缝三通的液压胀形工艺所需的设备吨位较大，目前国内主要用于小于DN400的标准壁厚三通的制造。其适用的成形材料为冷作硬化倾向相对较低的低碳钢、低合金钢、不锈钢，包括一些有色金属材料，如铜、铝、钛等。
2. 热压成形
三通热压成形是将大于三通直径的管坯，压扁约至三通直径的尺寸，
冷拔三通
冷拔三通
在拉伸支管的部位开一个孔；管坯经加热，放入成形模中，并在管坯内装入拉伸支管的冲模；在压力的作用下管坯被径向压缩，在径向压缩的过程中金属向支管方向流动并在冲模的拉伸下形成支管。整个过程是通过管坯的径向压缩和支管部位的拉伸过程而成形。与液压胀形三通不同的是，热压三通支管的金属是由管坯的径向运动进行补偿的，所以也称为径向补偿工艺。
由于采用加热后压制三通，材料成形所需要的设备吨位降低。热压三通对材料的适应性较宽，适用于低碳钢、合金钢、不锈钢的材料；特别是大直径和管壁偏厚的三通，通常采用这种成形工艺。
以材质划分
碳钢，铸钢，合金钢，不锈钢，铜，铝合金，塑料，氩硌沥，pvc等。
以制作方法划分
顶制、压制、锻制、铸造等。
以制造标准划分
国标、电标、化标、水标、美标、德标、日标、俄标等，具体如下：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.
