三(san)通為管(guan)(guan)(guan)件(jian)(jian)、管(guan)(guan)(guan)道連(lian)接件(jian)(jian)。又叫管(guan)(guan)(guan)件(jian)(jian)三(san)通或者三(san)通管(guan)(guan)(guan)件(jian)(jian)，三(san)通接頭(tou)，用在主管(guan)(guan)(guan)道要分支(zhi)管(guan)(guan)(guan)處。

　　三(san)(san)通是具(ju)有(you)(you)三(san)(san)個(ge)口(kou)(kou)子，即一(yi)(yi)個(ge)進口(kou)(kou)，兩個(ge)出口(kou)(kou)；或兩個(ge)進口(kou)(kou)，一(yi)(yi)個(ge)出口(kou)(kou)的一(yi)(yi)種化(hua)工管(guan)(guan)件(jian)，有(you)(you)T形與Y形，有(you)(you)等徑(jing)管(guan)(guan)口(kou)(kou)，也(ye)有(you)(you)異徑(jing)管(guan)(guan)口(kou)(kou)，用于三(san)(san)條相同或不同管(guan)(guan)路匯集(ji)處。三(san)(san)通的主要(yao)作用是改變流體方向(xiang)的。

　　不(bu)銹鋼(gang)三(san)(san)(san)通(tong)(tong)是用(yong)(yong)于管(guan)(guan)(guan)(guan)道(dao)分支(zhi)(zhi)處的(de)(de)(de)(de)一種管(guan)(guan)(guan)(guan)件。對(dui)于采用(yong)(yong)無縫管(guan)(guan)(guan)(guan)制造三(san)(san)(san)通(tong)(tong)來講，目前通(tong)(tong)常所采用(yong)(yong)的(de)(de)(de)(de)工藝(yi)有液(ye)(ye)(ye)壓(ya)(ya)脹(zhang)形(xing)(xing)和(he)熱壓(ya)(ya)成形(xing)(xing)兩(liang)種。不(bu)銹鋼(gang)三(san)(san)(san)通(tong)(tong)的(de)(de)(de)(de)液(ye)(ye)(ye)壓(ya)(ya)脹(zhang)形(xing)(xing)是通(tong)(tong)過金屬材(cai)(cai)料的(de)(de)(de)(de)軸向(xiang)補償脹(zhang)出(chu)支(zhi)(zhi)管(guan)(guan)(guan)(guan)的(de)(de)(de)(de)一種成形(xing)(xing)工藝(yi)。其過程是采用(yong)(yong)專用(yong)(yong)液(ye)(ye)(ye)壓(ya)(ya)機，將與三(san)(san)(san)通(tong)(tong)直徑(jing)相等的(de)(de)(de)(de)管(guan)(guan)(guan)(guan)坯內(nei)注入液(ye)(ye)(ye)體，通(tong)(tong)過液(ye)(ye)(ye)壓(ya)(ya)機的(de)(de)(de)(de)兩(liang)個(ge)水平側缸同步對(dui)中運動擠壓(ya)(ya)管(guan)(guan)(guan)(guan)坯，管(guan)(guan)(guan)(guan)坯受(shou)擠壓(ya)(ya)后(hou)體積(ji)變小，管(guan)(guan)(guan)(guan)坯內(nei)的(de)(de)(de)(de)液(ye)(ye)(ye)體隨管(guan)(guan)(guan)(guan)坯體積(ji)變小而壓(ya)(ya)力升高，當達到不(bu)銹鋼(gang)三(san)(san)(san)通(tong)(tong)支(zhi)(zhi)管(guan)(guan)(guan)(guan)脹(zhang)出(chu)所需要的(de)(de)(de)(de)壓(ya)(ya)力時，金屬材(cai)(cai)料在側缸和(he)管(guan)(guan)(guan)(guan)坯內(nei)液(ye)(ye)(ye)體壓(ya)(ya)力的(de)(de)(de)(de)雙重作用(yong)(yong)下(xia)沿模具內(nei)腔流動而脹(zhang)出(chu)支(zhi)(zhi)管(guan)(guan)(guan)(guan)