四通為管件(jian)、管道(dao)連接(jie)件(jian)。又叫管件(jian)四通或者四通管件(jian)，四通接(jie)頭，用在主管道(dao)要分支(zhi)管處。

四通(tong)有(you)等(deng)徑和異徑之(zhi)分，等(deng)徑四通(tong)的接管(guan)(guan)端部(bu)均(jun)為(wei)相同的尺寸；異徑的四通(tong)的主管(guan)(guan)接管(guan)(guan)尺寸相同，而支(zhi)管(guan)(guan)的接管(guan)(guan)尺寸小于(yu)主管(guan)(guan)的接管(guan)(guan)尺寸。四通(tong)是用(yong)于(yu)管(guan)(guan)道分支(zhi)處(chu)的一(yi)種(zhong)管(guan)(guan)件。四通(tong)廠家

四通(tong)(tong)(tong)熱壓(ya)(ya)成(cheng)(cheng)(cheng)形是將大(da)于四通(tong)(tong)(tong)直徑(jing)的管(guan)(guan)(guan)坯(pi)，壓(ya)(ya)扁(bian)約至(zhi)四通(tong)(tong)(tong)直徑(jing)的尺寸(cun)，在拉伸支(zhi)(zhi)管(guan)(guan)(guan)的部位開一(yi)個孔；管(guan)(guan)(guan)坯(pi)經(jing)加(jia)熱，放(fang)入成(cheng)(cheng)(cheng)形模中，并在管(guan)(guan)(guan)坯(pi)內裝入拉伸支(zhi)(zhi)管(guan)(guan)(guan)的沖模；在壓(ya)(ya)力的作用下(xia)管(guan)(guan)(guan)坯(pi)被徑(jing)向(xiang)(xiang)壓(ya)(ya)縮，在徑(jing)向(xiang)(xiang)壓(ya)(ya)縮的過程中金(jin)屬向(xiang)(xiang)支(zhi)(zhi)管(guan)(guan)(guan)方向(xiang)(xiang)流動并在沖模的拉伸下(xia)形成(cheng)(cheng)(cheng)支(zhi)(zhi)管(guan)(guan)(guan)。整個過程是通(tong)(tong)(tong)過管(guan)(guan)(guan)坯(pi)的徑(jing)向(xiang)(xiang)壓(ya)(ya)縮和支(zhi)(zhi)管(guan)(guan)(guan)部位的拉伸過程而成(cheng)(cheng)(cheng)形。與液壓(ya)(ya)脹(zhang)形四通(tong)(tong)(tong)不同的是，熱壓(ya)(ya)四通(tong)(tong)(tong)支(zhi)(zhi)管(guan)(guan)(guan)的金(jin)屬是由管(guan)(guan)(guan)坯(pi)的徑(jing)向(xiang)(xiang)運(yun)動進行補(bu)償的，所以也稱為(wei)徑(jing)向(xiang)(xiang)補(bu)償工藝。

由于采用加熱后(hou)壓制四通，材料成(cheng)形所(suo)需要的(de)設備噸位降低。熱壓四通對(dui)材料的(de)適(shi)應性(xing)較寬，適(shi)用于低碳鋼、合(he)金鋼、不銹鋼的(de)材料；特別是大直徑和(he)管壁偏厚的(de)四通，通常采用這種成(cheng)形工藝。

1.以材質劃分碳鋼(gang)，鑄(zhu)鋼(gang)，合金(jin)鋼(gang)，不銹鋼(gang)，銅，鋁合金(jin)，塑料，氬硌(luo)瀝，pvc等。

2.以制作(zuo)方法劃分(fen)可分(fen)為頂(ding)制、壓制、鍛(duan)制、鑄造等。

3.以制造標(biao)(biao)(biao)(biao)(biao)(biao)準(zhun)劃分(fen)可分(fen)為國(guo)標(biao)(biao)(biao)(biao)(biao)(biao)、電標(biao)(biao)(biao)(biao)(biao)(biao)、水標(biao)(biao)(biao)(biao)(biao)(biao)、美標(biao)(biao)(biao)(biao)(biao)(biao)、德(de)標(biao)(biao)(biao)(biao)(biao)(biao)、日標(biao)(biao)(biao)(biao)(biao)(biao)、俄標(biao)(biao)(biao)(biao)(biao)(biao)等,具(ju)體如下：GB/T12459,GB/T13401,ASME B16.9,SH3408,SH3409,HG/T21635,DL/T 695,SY/T 0510,DIN 2615　四通(tong)是三井財團等日本打(da)印機產品進軍中(zhong)國(guo)市場的跳板(ban)，也是犧(xi)牲(sheng)品。三井旗下的富士通(tong)、東芝、愛普生等借助(zhu)四通(tong)在中(zhong)國(guo)的銷售(shou)網絡和人脈關系打(da)開(kai)了中(zhong)國(guo)市場，而四通(tong)已經鮮有人知。這是日本財團慣(guan)用的手段。