①. 三通接頭是管件的一種，它的連接形式就是直接將三通與鋼管對焊，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》、ASMEB16.9《工廠制造的鍛軋制對焊管配件》、SH 3408《鋼制對焊無縫管件》、SH 3409《鋼板制對焊管件》、HG/T21635《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》。

   ②. 三(san)(san)(san)(san)通(tong)(tong)(tong)(tong)(tong)(tong)(tong)(tong)按(an)照(zhao)管(guan)件(jian)口(kou)徑(jing)分一(yi)般有(you)等(deng)徑(jing)三(san)(san)(san)(san)通(tong)(tong)(tong)(tong)(tong)(tong)(tong)(tong)［圖16.25（a）］、異(yi)徑(jing)三(san)(san)(san)(san)通(tong)(tong)(tong)(tong)(tong)(tong)(tong)(tong)［圖16.25（b）］等(deng)。按(an)照(zhao)支管(guan)方(fang)向分有(you)正三(san)(san)(san)(san)通(tong)(tong)(tong)(tong)(tong)(tong)(tong)(tong)和(he)斜三(san)(san)(san)(san)通(tong)(tong)(tong)(tong)(tong)(tong)(tong)(tong)（y形三(san)(san)(san)(san)通(tong)(tong)(tong)(tong)(tong)(tong)(tong)(tong)），斜三(san)(san)(san)(san)通(tong)(tong)(tong)(tong)(tong)(tong)(tong)(tong)常(chang)(chang)常(chang)(chang)代替一(yi)般正三(san)(san)(san)(san)通(tong)(tong)(tong)(tong)(tong)(tong)(tong)(tong)，用于(yu)輸(shu)送(song)有(you)固(gu)體顆(ke)粒或沖刷腐蝕較嚴(yan)重的管(guan)道上。按(an)照(zhao)材料分有(you)碳(tan)鋼(gang)(gang)、合(he)金鋼(gang)(gang)、不銹鋼(gang)(gang)、銅(tong)、PVC等(deng)三(san)(san)(san)(san)通(tong)(tong)(tong)(tong)(tong)(tong)(tong)(tong)。按(an)照(zhao)連接方(fang)式分有(you)普通(tong)(tong)(tong)(tong)(tong)(tong)(tong)(tong)三(san)(san)(san)(san)通(tong)(tong)(tong)(tong)(tong)(tong)(tong)(tong)、螺紋三(san)(san)(san)(san)通(tong)(tong)(tong)(tong)(tong)(tong)(tong)(tong)、卡套三(san)(san)(san)(san)通(tong)(tong)(tong)(tong)(tong)(tong)(tong)(tong)、承插三(san)(san)(san)(san)通(tong)(tong)(tong)(tong)(tong)(tong)(tong)(tong)。

   ③. 三(san)(san)通(tong)(tong)(tong)接頭(tou)成(cheng)形(xing)(xing)是(shi)將(jiang)大于(yu)三(san)(san)通(tong)(tong)(tong)直(zhi)徑(jing)(jing)的管(guan)(guan)(guan)坯，壓(ya)(ya)扁(bian)至約(yue)三(san)(san)通(tong)(tong)(tong)直(zhi)徑(jing)(jing)的尺寸(cun)，在(zai)(zai)拉伸支(zhi)(zhi)(zhi)(zhi)管(guan)(guan)(guan)的部(bu)位開一個(ge)孔；管(guan)(guan)(guan)坯經加熱，放(fang)入(ru)成(cheng)形(xing)(xing)模中，并(bing)在(zai)(zai)管(guan)(guan)(guan)坯內裝入(ru)拉伸支(zhi)(zhi)(zhi)(zhi)管(guan)(guan)(guan)的沖模；在(zai)(zai)壓(ya)(ya)力(li)的作用(yong)下(xia)(xia)管(guan)(guan)(guan)坯被徑(jing)(jing)向(xiang)壓(ya)(ya)縮(suo)，在(zai)(zai)徑(jing)(jing)向(xiang)壓(ya)(ya)縮(suo)的過程中金屬向(xiang)支(zhi)(zhi)(zhi)(zhi)管(guan)(guan)(guan)方向(xiang)流動(dong)并(bing)在(zai)(zai)沖模的拉伸下(xia)(xia)形(xing)(xing)成(cheng)支(zhi)(zhi)(zhi)(zhi)管(guan)(guan)(guan)。整個(ge)過程是(shi)通(tong)(tong)(tong)過管(guan)(guan)(guan)坯的徑(jing)(jing)向(xiang)壓(ya)(ya)縮(suo)和支(zhi)(zhi)(zhi)(zhi)管(guan)(guan)(guan)部(bu)位的拉伸過程而成(cheng)形(xing)(xing)。與(yu)液壓(ya)(ya)脹形(xing)(xing)三(san)(san)通(tong)(tong)(tong)不同(tong)的是(shi)，三(san)(san)通(tong)(tong)(tong)接頭(tou)支(zhi)(zhi)(zhi)(zhi)管(guan)(guan)(guan)的金屬是(shi)由(you)管(guan)(guan)(guan)坯的徑(jing)(jing)向(xiang)運動(dong)進行補償(chang)的，所以也稱(cheng)為徑(jing)(jing)向(xiang)補償(chang)工藝(yi)。由(you)于(yu)采用(yong)加熱后(hou)壓(ya)(ya)制(zhi)三(san)(san)通(tong)(tong)(tong)，材料(liao)(liao)成(cheng)形(xing)(xing)所需要(yao)的設備噸位降(jiang)低。熱壓(ya)(ya)三(san)(san)通(tong)(tong)(tong)對材料(liao)(liao)的適應性較寬(kuan)，適用(yong)于(yu)低碳鋼、合金鋼、不銹鋼的材料(liao)(liao)，特別是(shi)大直(zhi)徑(jing)(jing)和管(guan)(guan)(guan)壁偏厚的三(san)(san)通(tong)(tong)(tong)，通(tong)(tong)(tong)常采用(yong)這種成(cheng)形(xing)(xing)工藝(yi)。

   ④. 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(si)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 B 16.9，SH 3408，SH 3409，HG／T21635，DL／T 695，SY／T 0510，DIN 2615等。四通典型圖見圖16.26。

   ⑤. 對(dui)于(yu)異徑(jing)(jing)(jing)三(san)通(tong)，首(shou)(shou)先(xian)給出(chu)最大(da)(da)端(duan)的(de)(de)(de)公(gong)稱(cheng)(cheng)通(tong)徑(jing)(jing)(jing)，然后(hou)是(shi)與最大(da)(da)端(duan)相(xiang)對(dui)應(ying)的(de)(de)(de)那(nei)一(yi)(yi)端(duan)的(de)(de)(de)公(gong)稱(cheng)(cheng)通(tong)徑(jing)(jing)(jing)，最后(hou)給出(chu)支(zhi)管端(duan)的(de)(de)(de)公(gong)稱(cheng)(cheng)通(tong)徑(jing)(jing)(jing)；對(dui)于(yu)異徑(jing)(jing)(jing)四(si)通(tong)，首(shou)(shou)先(xian)給出(chu)最大(da)(da)端(duan)的(de)(de)(de)公(gong)稱(cheng)(cheng)通(tong)徑(jing)(jing)(jing)，其次是(shi)與最大(da)(da)端(duan)相(xiang)對(dui)應(ying)的(de)(de)(de)另一(yi)(yi)端(duan)的(de)(de)(de)公(gong)稱(cheng)(cheng)通(tong)徑(jing)(jing)(jing)，第三(san)個給出(chu)的(de)(de)(de)是(shi)另外兩端(duan)中(zhong)較(jiao)大(da)(da)端(duan)的(de)(de)(de)公(gong)稱(cheng)(cheng)通(tong)徑(jing)(jing)(jing)，最后(hou)給出(chu)剩余一(yi)(yi)端(duan)的(de)(de)(de)公(gong)稱(cheng)(cheng)通(tong)徑(jing)(jing)(jing)，見圖(tu)16.27。