三通接頭是不銹(xiu)鋼管件(jian)的一種，它的連接形式就是直接將不銹(xiu)鋼三通與鋼管對焊，三通接頭的主要制造標準一般是GB/T 12459《鋼制無縫焊接管件》、GB/T 13401《鋼板制對焊管件》、ASME B16.9《工廠制造的鍛軋制對焊管配件》、SH/T 3408《鋼制對焊無縫管件》、SH/T3409《鋼板制對焊管件》、HG/T 21635《碳鋼、低合金鋼無縫對焊管件》、HG/T 21631《鋼制有縫對焊管件》、SY/T 0510《鋼制對焊管件》。
①. 按照(zhao)管件口徑(jing)分一般有等(deng)徑(jing)三(san)通(tong)(tong)（straight tee），異(yi)徑(jing)三(san)通(tong)(tong)（reducing tee）等(deng)。
②. 按照支管方向分有(you)正三通(tong)和斜(xie)三通(tong)（Y形三通(tong)），斜(xie)三通(tong)常常代替一(yi)般(ban)正三通(tong)，用于輸送有(you)固體顆粒(li)或沖刷腐蝕較嚴重(zhong)的管道上。
③. 按照材(cai)料分有碳鋼(gang)、合金鋼(gang)、不銹鋼(gang)、銅、PVC等三通。
④. 按照連接方式(shi)分(fen)有(you)普通(tong)三通(tong)、螺紋三通(tong)、卡(ka)套三通(tong)、承插三通(tong)。典型三通(tong)及連接見圖4.6.11。
不(bu)銹鋼(gang)三(san)(san)通(tong)(tong)(tong)接頭(tou)(tou)成(cheng)(cheng)形(xing)是(shi)將大于三(san)(san)通(tong)(tong)(tong)直(zhi)徑(jing)(jing)的(de)管(guan)(guan)(guan)坯(pi)，壓(ya)(ya)扁約至三(san)(san)通(tong)(tong)(tong)直(zhi)徑(jing)(jing)的(de)尺寸，在(zai)(zai)(zai)拉伸(shen)支(zhi)(zhi)管(guan)(guan)(guan)的(de)部位(wei)開一個孔；管(guan)(guan)(guan)坯(pi)經加熱，放入(ru)成(cheng)(cheng)形(xing)模(mo)中，并(bing)在(zai)(zai)(zai)管(guan)(guan)(guan)坯(pi)內裝入(ru)拉伸(shen)支(zhi)(zhi)管(guan)(guan)(guan)的(de)沖模(mo)；在(zai)(zai)(zai)壓(ya)(ya)力的(de)作用(yong)(yong)下管(guan)(guan)(guan)坯(pi)被徑(jing)(jing)向(xiang)(xiang)壓(ya)(ya)縮，在(zai)(zai)(zai)徑(jing)(jing)向(xiang)(xiang)壓(ya)(ya)縮的(de)過程(cheng)中金(jin)屬(shu)向(xiang)(xiang)支(zhi)(zhi)管(guan)(guan)(guan)方向(xiang)(xiang)流動(dong)并(bing)在(zai)(zai)(zai)沖模(mo)的(de)拉伸(shen)下形(xing)成(cheng)(cheng)支(zhi)(zhi)管(guan)(guan)(guan)。整個過程(cheng)是(shi)通(tong)(tong)(tong)過管(guan)(guan)(guan)坯(pi)的(de)徑(jing)(jing)向(xiang)(xiang)壓(ya)(ya)縮和支(zhi)(zhi)管(guan)(guan)(guan)部位(wei)的(de)拉伸(shen)過程(cheng)而成(cheng)(cheng)形(xing)。與液壓(ya)(ya)脹形(xing)三(san)(san)通(tong)(tong)(tong)不(bu)同的(de)是(shi)，三(san)(san)通(tong)(tong)(tong)接頭(tou)(tou)支(zhi)(zhi)管(guan)(guan)(guan)的(de)金(jin)屬(shu)是(shi)由管(guan)(guan)(guan)坯(pi)的(de)徑(jing)(jing)向(xiang)(xiang)運動(dong)進行補(bu)(bu)償(chang)的(de)，所以也稱為徑(jing)(jing)向(xiang)(xiang)補(bu)(bu)償(chang)工(gong)藝。由于采(cai)用(yong)(yong)加熱后壓(ya)(ya)制(zhi)三(san)(san)通(tong)(tong)(tong)，材(cai)料成(cheng)(cheng)形(xing)所需要的(de)設(she)備噸位(wei)降(jiang)低。熱壓(ya)(ya)三(san)(san)通(tong)(tong)(tong)對材(cai)料的(de)適(shi)應性較寬，適(shi)用(yong)(yong)于低碳(tan)鋼(gang)、合金(jin)鋼(gang)、不(bu)銹鋼(gang)的(de)材(cai)料；特別(bie)是(shi)大直(zhi)徑(jing)(jing)和管(guan)(guan)(guan)壁偏厚的(de)三(san)(san)通(tong)(tong)(tong)，通(tong)(tong)(tong)常采(cai)用(yong)(yong)這種成(cheng)(cheng)形(xing)工(gong)藝。
不(bu)銹鋼(gang)四通(tong)為管件、管道連接件，用在主管道要分支管處，又稱管件四通、四通管件、四通接頭。四通有等徑和異徑之分，等徑四通的接管端部均為相同的尺寸；異徑的四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。對于采用無縫管制造四通來講，目前通常所采用的工藝有液壓脹形和熱壓成形兩種。四通以制作方法劃分可分為頂制、壓制、鍛制、鑄造等。制造標準有GB/T 12459，GB/T 13401，ASME B16.9，SH/T 3408，SH/T 3409，HG/T 21635，DL/T 695，SY/T 0510，DIN 2615等。典型四通見圖4.6.12。
對(dui)于(yu)異(yi)徑(jing)三(san)通(tong)(tong)(tong)(tong)，首(shou)先(xian)給(gei)出(chu)最大端(duan)(duan)(duan)(duan)的(de)公稱(cheng)通(tong)(tong)(tong)(tong)徑(jing)，然(ran)后是(shi)與最大端(duan)(duan)(duan)(duan)相對(dui)應(ying)的(de)那一端(duan)(duan)(duan)(duan)的(de)公稱(cheng)通(tong)(tong)(tong)(tong)徑(jing)，最后給(gei)出(chu)支管(guan)瑞的(de)公稱(cheng)通(tong)(tong)(tong)(tong)徑(jing)；對(dui)于(yu)異(yi)徑(jing)四通(tong)(tong)(tong)(tong)，首(shou)先(xian)給(gei)出(chu)最大端(duan)(duan)(duan)(duan)的(de)公稱(cheng)通(tong)(tong)(tong)(tong)徑(jing)，其次是(shi)與最大端(duan)(duan)(duan)(duan)相對(dui)應(ying)的(de)另(ling)一端(duan)(duan)(duan)(duan)的(de)公稱(cheng)通(tong)(tong)(tong)(tong)徑(jing)，第三(san)個給(gei)出(chu)的(de)是(shi)另(ling)外兩端(duan)(duan)(duan)(duan)中的(de)較大端(duan)(duan)(duan)(duan)的(de)公稱(cheng)通(tong)(tong)(tong)(tong)徑(jing)，最后給(gei)出(chu)剩余一端(duan)(duan)(duan)(duan)的(de)公稱(cheng)通(tong)(tong)(tong)(tong)徑(jing)（見圖(tu)4.6.13）。
