三通接頭是不銹鋼管件(jian)的一種，它的連接形式就是直接將不銹鋼三通(tong)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(jian)口徑分一般有等徑三通（straight tee），異徑三通（reducing tee）等。

  ②. 按照支管方向分(fen)有正(zheng)三(san)通(tong)(tong)和斜(xie)三(san)通(tong)(tong)（Y形三(san)通(tong)(tong)），斜(xie)三(san)通(tong)(tong)常常代替一(yi)般(ban)正(zheng)三(san)通(tong)(tong)，用(yong)于輸送有固體(ti)顆粒(li)或沖刷腐蝕較嚴重(zhong)的管道上。

  ③. 按(an)照材料(liao)分有(you)碳鋼(gang)、合(he)金鋼(gang)、不銹鋼(gang)、銅、PVC等三通。

  ④. 按照連接方式分有(you)普(pu)通(tong)(tong)三(san)(san)通(tong)(tong)、螺紋三(san)(san)通(tong)(tong)、卡(ka)套(tao)三(san)(san)通(tong)(tong)、承(cheng)插(cha)三(san)(san)通(tong)(tong)。典型三(san)(san)通(tong)(tong)及(ji)連接見圖(tu)4.6.11。

  不銹鋼(gang)三(san)通(tong)(tong)(tong)接頭成(cheng)(cheng)形是(shi)將大(da)于(yu)三(san)通(tong)(tong)(tong)直徑(jing)(jing)的(de)(de)(de)(de)(de)管(guan)(guan)(guan)(guan)坯(pi)(pi)，壓(ya)(ya)扁約至三(san)通(tong)(tong)(tong)直徑(jing)(jing)的(de)(de)(de)(de)(de)尺(chi)寸，在拉(la)(la)伸(shen)(shen)(shen)支管(guan)(guan)(guan)(guan)的(de)(de)(de)(de)(de)部位(wei)(wei)開一個孔；管(guan)(guan)(guan)(guan)坯(pi)(pi)經(jing)加熱(re)，放(fang)入成(cheng)(cheng)形模中，并在管(guan)(guan)(guan)(guan)坯(pi)(pi)內(nei)裝(zhuang)入拉(la)(la)伸(shen)(shen)(shen)支管(guan)(guan)(guan)(guan)的(de)(de)(de)(de)(de)沖模；在壓(ya)(ya)力的(de)(de)(de)(de)(de)作用(yong)(yong)下管(guan)(guan)(guan)(guan)坯(pi)(pi)被徑(jing)(jing)向(xiang)壓(ya)(ya)縮(suo)，在徑(jing)(jing)向(xiang)壓(ya)(ya)縮(suo)的(de)(de)(de)(de)(de)過(guo)程中金屬(shu)(shu)向(xiang)支管(guan)(guan)(guan)(guan)方向(xiang)流動并在沖模的(de)(de)(de)(de)(de)拉(la)(la)伸(shen)(shen)(shen)下形成(cheng)(cheng)支管(guan)(guan)(guan)(guan)。整個過(guo)程是(shi)通(tong)(tong)(tong)過(guo)管(guan)(guan)(guan)(guan)坯(pi)(pi)的(de)(de)(de)(de)(de)徑(jing)(jing)向(xiang)壓(ya)(ya)縮(suo)和支管(guan)(guan)(guan)(guan)部位(wei)(wei)的(de)(de)(de)(de)(de)拉(la)(la)伸(shen)(shen)(shen)過(guo)程而成(cheng)(cheng)形。與液壓(ya)(ya)脹形三(san)通(tong)(tong)(tong)不同的(de)(de)(de)(de)(de)是(shi)，三(san)通(tong)(tong)(tong)接頭支管(guan)(guan)(guan)(guan)的(de)(de)(de)(de)(de)金屬(shu)(shu)是(shi)由(you)管(guan)(guan)(guan)(guan)坯(pi)(pi)的(de)(de)(de)(de)(de)徑(jing)(jing)向(xiang)運動進行補償(chang)的(de)(de)(de)(de)(de)，所(suo)以也稱為徑(jing)(jing)向(xiang)補償(chang)工藝。由(you)于(yu)采用(yong)(yong)加熱(re)后壓(ya)(ya)制(zhi)三(san)通(tong)(tong)(tong)，材料成(cheng)(cheng)形所(suo)需要的(de)(de)(de)(de)(de)設備噸位(wei)(wei)降低。熱(re)壓(ya)(ya)三(san)通(tong)(tong)(tong)對材料的(de)(de)(de)(de)(de)適(shi)應性(xing)較寬，適(shi)用(yong)(yong)于(yu)低碳(tan)鋼(gang)、合金鋼(gang)、不銹鋼(gang)的(de)(de)(de)(de)(de)材料；特別是(shi)大(da)直徑(jing)(jing)和管(guan)(guan)(guan)(guan)壁偏厚的(de)(de)(de)(de)(de)三(san)通(tong)(tong)(tong)，通(tong)(tong)(tong)常采用(yong)(yong)這種成(cheng)(cheng)形工藝。

   不銹鋼四通為管件、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(dui)于(yu)異徑(jing)三通(tong)，首(shou)(shou)先(xian)給出(chu)(chu)最(zui)大端(duan)(duan)(duan)的(de)(de)(de)公(gong)(gong)(gong)(gong)稱通(tong)徑(jing)，然后(hou)是(shi)(shi)與(yu)最(zui)大端(duan)(duan)(duan)相對(dui)應(ying)的(de)(de)(de)那一端(duan)(duan)(duan)的(de)(de)(de)公(gong)(gong)(gong)(gong)稱通(tong)徑(jing)，最(zui)后(hou)給出(chu)(chu)支管瑞的(de)(de)(de)公(gong)(gong)(gong)(gong)稱通(tong)徑(jing)；對(dui)于(yu)異徑(jing)四通(tong)，首(shou)(shou)先(xian)給出(chu)(chu)最(zui)大端(duan)(duan)(duan)的(de)(de)(de)公(gong)(gong)(gong)(gong)稱通(tong)徑(jing)，其次是(shi)(shi)與(yu)最(zui)大端(duan)(duan)(duan)相對(dui)應(ying)的(de)(de)(de)另(ling)一端(duan)(duan)(duan)的(de)(de)(de)公(gong)(gong)(gong)(gong)稱通(tong)徑(jing)，第三個給出(chu)(chu)的(de)(de)(de)是(shi)(shi)另(ling)外兩端(duan)(duan)(duan)中的(de)(de)(de)較大端(duan)(duan)(duan)的(de)(de)(de)公(gong)(gong)(gong)(gong)稱通(tong)徑(jing)，最(zui)后(hou)給出(chu)(chu)剩余一端(duan)(duan)(duan)的(de)(de)(de)公(gong)(gong)(gong)(gong)稱通(tong)徑(jing)（見圖(tu)4.6.13）。