三通接頭是不銹鋼管件的一種，它的連接形式就是直接將不(bu)銹鋼三通與鋼管對焊，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. 按照管件口(kou)徑分(fen)一般有等(deng)徑三通（straight tee），異徑三通（reducing tee）等(deng)。

  ②. 按照(zhao)支管方向分有正三(san)通(tong)和斜(xie)三(san)通(tong)（Y形三(san)通(tong)），斜(xie)三(san)通(tong)常常代替一(yi)般(ban)正三(san)通(tong)，用(yong)于輸(shu)送有固體(ti)顆(ke)粒或沖刷腐蝕較(jiao)嚴重的管道(dao)上。

  ③. 按照材料分有(you)碳(tan)鋼(gang)、合(he)金鋼(gang)、不銹鋼(gang)、銅、PVC等(deng)三通(tong)。

  ④. 按照(zhao)連(lian)(lian)接(jie)方式分有普通三(san)(san)通、螺紋三(san)(san)通、卡套三(san)(san)通、承插三(san)(san)通。典(dian)型(xing)三(san)(san)通及連(lian)(lian)接(jie)見(jian)圖4.6.11。

  不銹鋼三(san)通(tong)(tong)(tong)接頭成(cheng)(cheng)形是(shi)(shi)將大(da)于(yu)三(san)通(tong)(tong)(tong)直徑(jing)的(de)(de)(de)(de)管(guan)(guan)(guan)坯(pi)(pi)(pi)，壓(ya)扁約至三(san)通(tong)(tong)(tong)直徑(jing)的(de)(de)(de)(de)尺(chi)寸，在(zai)拉伸(shen)支(zhi)管(guan)(guan)(guan)的(de)(de)(de)(de)部位(wei)開一個孔；管(guan)(guan)(guan)坯(pi)(pi)(pi)經加熱(re)，放入成(cheng)(cheng)形模中，并在(zai)管(guan)(guan)(guan)坯(pi)(pi)(pi)內(nei)裝(zhuang)入拉伸(shen)支(zhi)管(guan)(guan)(guan)的(de)(de)(de)(de)沖模；在(zai)壓(ya)力(li)的(de)(de)(de)(de)作用下(xia)管(guan)(guan)(guan)坯(pi)(pi)(pi)被徑(jing)向(xiang)壓(ya)縮(suo)，在(zai)徑(jing)向(xiang)壓(ya)縮(suo)的(de)(de)(de)(de)過(guo)程中金(jin)屬向(xiang)支(zhi)管(guan)(guan)(guan)方向(xiang)流(liu)動(dong)并在(zai)沖模的(de)(de)(de)(de)拉伸(shen)下(xia)形成(cheng)(cheng)支(zhi)管(guan)(guan)(guan)。整個過(guo)程是(shi)(shi)通(tong)(tong)(tong)過(guo)管(guan)(guan)(guan)坯(pi)(pi)(pi)的(de)(de)(de)(de)徑(jing)向(xiang)壓(ya)縮(suo)和(he)支(zhi)管(guan)(guan)(guan)部位(wei)的(de)(de)(de)(de)拉伸(shen)過(guo)程而成(cheng)(cheng)形。與液壓(ya)脹形三(san)通(tong)(tong)(tong)不同的(de)(de)(de)(de)是(shi)(shi)，三(san)通(tong)(tong)(tong)接頭支(zhi)管(guan)(guan)(guan)的(de)(de)(de)(de)金(jin)屬是(shi)(shi)由(you)管(guan)(guan)(guan)坯(pi)(pi)(pi)的(de)(de)(de)(de)徑(jing)向(xiang)運動(dong)進行補償(chang)的(de)(de)(de)(de)，所以也稱為徑(jing)向(xiang)補償(chang)工藝。由(you)于(yu)采用加熱(re)后壓(ya)制(zhi)三(san)通(tong)(tong)(tong)，材(cai)料(liao)成(cheng)(cheng)形所需要的(de)(de)(de)(de)設備(bei)噸位(wei)降(jiang)低。熱(re)壓(ya)三(san)通(tong)(tong)(tong)對(dui)材(cai)料(liao)的(de)(de)(de)(de)適(shi)應性較寬，適(shi)用于(yu)低碳鋼、合金(jin)鋼、不銹鋼的(de)(de)(de)(de)材(cai)料(liao)；特別是(shi)(shi)大(da)直徑(jing)和(he)管(guan)(guan)(guan)壁偏厚的(de)(de)(de)(de)三(san)通(tong)(tong)(tong)，通(tong)(tong)(tong)常采用這(zhe)種成(cheng)(cheng)形工藝。

   不(bu)銹(xiu)鋼四通為管件、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。

  對于異徑(jing)三(san)通(tong)(tong)(tong)，首先(xian)給(gei)出(chu)最(zui)大(da)端(duan)(duan)(duan)(duan)的(de)(de)公(gong)(gong)(gong)(gong)稱(cheng)通(tong)(tong)(tong)徑(jing)，然后是與(yu)最(zui)大(da)端(duan)(duan)(duan)(duan)相對應(ying)的(de)(de)那一端(duan)(duan)(duan)(duan)的(de)(de)公(gong)(gong)(gong)(gong)稱(cheng)通(tong)(tong)(tong)徑(jing)，最(zui)后給(gei)出(chu)支管瑞的(de)(de)公(gong)(gong)(gong)(gong)稱(cheng)通(tong)(tong)(tong)徑(jing)；對于異徑(jing)四通(tong)(tong)(tong)，首先(xian)給(gei)出(chu)最(zui)大(da)端(duan)(duan)(duan)(duan)的(de)(de)公(gong)(gong)(gong)(gong)稱(cheng)通(tong)(tong)(tong)徑(jing)，其次是與(yu)最(zui)大(da)端(duan)(duan)(duan)(duan)相對應(ying)的(de)(de)另一端(duan)(duan)(duan)(duan)的(de)(de)公(gong)(gong)(gong)(gong)稱(cheng)通(tong)(tong)(tong)徑(jing)，第(di)三(san)個給(gei)出(chu)的(de)(de)是另外(wai)兩(liang)端(duan)(duan)(duan)(duan)中的(de)(de)較大(da)端(duan)(duan)(duan)(duan)的(de)(de)公(gong)(gong)(gong)(gong)稱(cheng)通(tong)(tong)(tong)徑(jing)，最(zui)后給(gei)出(chu)剩(sheng)余一端(duan)(duan)(duan)(duan)的(de)(de)公(gong)(gong)(gong)(gong)稱(cheng)通(tong)(tong)(tong)徑(jing)（見圖4.6.13）。