三通接頭是不銹鋼管(guan)件的一種，它的連接形式就是直接將不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(jian)口徑(jing)分(fen)一般有等徑(jing)三通(tong)(tong)（straight tee），異(yi)徑(jing)三通(tong)(tong)（reducing tee）等。

  ②. 按照支(zhi)管方向分有正(zheng)(zheng)三(san)(san)通(tong)(tong)和斜三(san)(san)通(tong)(tong)（Y形(xing)三(san)(san)通(tong)(tong)），斜三(san)(san)通(tong)(tong)常(chang)常(chang)代替一般正(zheng)(zheng)三(san)(san)通(tong)(tong)，用于(yu)輸送有固體顆粒或沖刷(shua)腐蝕(shi)較嚴(yan)重(zhong)的(de)管道上。

  ③. 按照材(cai)料分有碳鋼(gang)、合金鋼(gang)、不銹鋼(gang)、銅(tong)、PVC等三通。

  ④. 按(an)照連接方式分(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(tu)4.6.11。

  不銹鋼(gang)三(san)(san)通(tong)(tong)(tong)接(jie)頭成(cheng)形(xing)是(shi)(shi)將(jiang)大于(yu)三(san)(san)通(tong)(tong)(tong)直(zhi)徑(jing)(jing)的(de)(de)(de)管(guan)(guan)(guan)(guan)(guan)坯(pi)，壓(ya)(ya)(ya)扁約至三(san)(san)通(tong)(tong)(tong)直(zhi)徑(jing)(jing)的(de)(de)(de)尺寸，在(zai)(zai)(zai)拉(la)伸(shen)支管(guan)(guan)(guan)(guan)(guan)的(de)(de)(de)部位開一個孔(kong)；管(guan)(guan)(guan)(guan)(guan)坯(pi)經加(jia)熱，放入(ru)成(cheng)形(xing)模(mo)中，并在(zai)(zai)(zai)管(guan)(guan)(guan)(guan)(guan)坯(pi)內裝入(ru)拉(la)伸(shen)支管(guan)(guan)(guan)(guan)(guan)的(de)(de)(de)沖模(mo)；在(zai)(zai)(zai)壓(ya)(ya)(ya)力(li)的(de)(de)(de)作用(yong)下管(guan)(guan)(guan)(guan)(guan)坯(pi)被徑(jing)(jing)向(xiang)(xiang)壓(ya)(ya)(ya)縮，在(zai)(zai)(zai)徑(jing)(jing)向(xiang)(xiang)壓(ya)(ya)(ya)縮的(de)(de)(de)過(guo)(guo)程中金屬向(xiang)(xiang)支管(guan)(guan)(guan)(guan)(guan)方向(xiang)(xiang)流動并在(zai)(zai)(zai)沖模(mo)的(de)(de)(de)拉(la)伸(shen)下形(xing)成(cheng)支管(guan)(guan)(guan)(guan)(guan)。整個過(guo)(guo)程是(shi)(shi)通(tong)(tong)(tong)過(guo)(guo)管(guan)(guan)(guan)(guan)(guan)坯(pi)的(de)(de)(de)徑(jing)(jing)向(xiang)(xiang)壓(ya)(ya)(ya)縮和支管(guan)(guan)(guan)(guan)(guan)部位的(de)(de)(de)拉(la)伸(shen)過(guo)(guo)程而成(cheng)形(xing)。與液壓(ya)(ya)(ya)脹形(xing)三(san)(san)通(tong)(tong)(tong)不同的(de)(de)(de)是(shi)(shi)，三(san)(san)通(tong)(tong)(tong)接(jie)頭支管(guan)(guan)(guan)(guan)(guan)的(de)(de)(de)金屬是(shi)(shi)由管(guan)(guan)(guan)(guan)(guan)坯(pi)的(de)(de)(de)徑(jing)(jing)向(xiang)(xiang)運動進(jin)行補(bu)償(chang)的(de)(de)(de)，所以也稱為徑(jing)(jing)向(xiang)(xiang)補(bu)償(chang)工藝(yi)。由于(yu)采用(yong)加(jia)熱后壓(ya)(ya)(ya)制三(san)(san)通(tong)(tong)(tong)，材(cai)料成(cheng)形(xing)所需要的(de)(de)(de)設備噸位降(jiang)低(di)。熱壓(ya)(ya)(ya)三(san)(san)通(tong)(tong)(tong)對材(cai)料的(de)(de)(de)適(shi)應(ying)性較寬，適(shi)用(yong)于(yu)低(di)碳鋼(gang)、合(he)金鋼(gang)、不銹鋼(gang)的(de)(de)(de)材(cai)料；特別是(shi)(shi)大直(zhi)徑(jing)(jing)和管(guan)(guan)(guan)(guan)(guan)壁偏(pian)厚的(de)(de)(de)三(san)(san)通(tong)(tong)(tong)，通(tong)(tong)(tong)常采用(yong)這種成(cheng)形(xing)工藝(yi)。

   不銹鋼(gang)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)于異徑(jing)(jing)三通(tong)(tong)(tong)，首(shou)先(xian)給出(chu)最(zui)大(da)(da)端的(de)(de)公(gong)(gong)稱(cheng)(cheng)(cheng)通(tong)(tong)(tong)徑(jing)(jing)，然后(hou)(hou)是與最(zui)大(da)(da)端相對(dui)應的(de)(de)那一(yi)端的(de)(de)公(gong)(gong)稱(cheng)(cheng)(cheng)通(tong)(tong)(tong)徑(jing)(jing)，最(zui)后(hou)(hou)給出(chu)支管瑞(rui)的(de)(de)公(gong)(gong)稱(cheng)(cheng)(cheng)通(tong)(tong)(tong)徑(jing)(jing)；對(dui)于異徑(jing)(jing)四通(tong)(tong)(tong)，首(shou)先(xian)給出(chu)最(zui)大(da)(da)端的(de)(de)公(gong)(gong)稱(cheng)(cheng)(cheng)通(tong)(tong)(tong)徑(jing)(jing)，其(qi)次是與最(zui)大(da)(da)端相對(dui)應的(de)(de)另一(yi)端的(de)(de)公(gong)(gong)稱(cheng)(cheng)(cheng)通(tong)(tong)(tong)徑(jing)(jing)，第三個給出(chu)的(de)(de)是另外兩(liang)端中的(de)(de)較大(da)(da)端的(de)(de)公(gong)(gong)稱(cheng)(cheng)(cheng)通(tong)(tong)(tong)徑(jing)(jing)，最(zui)后(hou)(hou)給出(chu)剩(sheng)余一(yi)端的(de)(de)公(gong)(gong)稱(cheng)(cheng)(cheng)通(tong)(tong)(tong)徑(jing)(jing)（見(jian)圖4.6.13）。