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)通(tong)(tong)(tong)(tong)(tong)按(an)照管件(jian)口(kou)徑(jing)分(fen)一般有(you)(you)(you)等徑(jing)三(san)通(tong)(tong)(tong)(tong)(tong)［圖16.25（a）］、異(yi)徑(jing)三(san)通(tong)(tong)(tong)(tong)(tong)［圖16.25（b）］等。按(an)照支管方向分(fen)有(you)(you)(you)正三(san)通(tong)(tong)(tong)(tong)(tong)和斜三(san)通(tong)(tong)(tong)(tong)(tong)（y形三(san)通(tong)(tong)(tong)(tong)(tong)），斜三(san)通(tong)(tong)(tong)(tong)(tong)常常代替一般正三(san)通(tong)(tong)(tong)(tong)(tong)，用于輸送有(you)(you)(you)固體顆(ke)粒或沖刷腐蝕(shi)較嚴(yan)重(zhong)的管道上。按(an)照材料分(fen)有(you)(you)(you)碳(tan)鋼(gang)、合金鋼(gang)、不銹鋼(gang)、銅、PVC等三(san)通(tong)(tong)(tong)(tong)(tong)。按(an)照連接方式(shi)分(fen)有(you)(you)(you)普通(tong)(tong)(tong)(tong)(tong)三(san)通(tong)(tong)(tong)(tong)(tong)、螺紋(wen)三(san)通(tong)(tong)(tong)(tong)(tong)、卡套三(san)通(tong)(tong)(tong)(tong)(tong)、承插三(san)通(tong)(tong)(tong)(tong)(tong)。
③. 三(san)(san)(san)通(tong)接頭(tou)成(cheng)(cheng)形(xing)(xing)是將大于三(san)(san)(san)通(tong)直(zhi)徑(jing)(jing)的(de)管(guan)坯(pi)，壓(ya)(ya)(ya)(ya)扁至約三(san)(san)(san)通(tong)直(zhi)徑(jing)(jing)的(de)尺寸，在(zai)(zai)拉(la)伸支(zhi)(zhi)管(guan)的(de)部位(wei)開一(yi)個孔(kong)；管(guan)坯(pi)經加熱(re)，放(fang)入成(cheng)(cheng)形(xing)(xing)模(mo)中(zhong)，并在(zai)(zai)管(guan)坯(pi)內裝入拉(la)伸支(zhi)(zhi)管(guan)的(de)沖模(mo)；在(zai)(zai)壓(ya)(ya)(ya)(ya)力的(de)作用下管(guan)坯(pi)被徑(jing)(jing)向(xiang)壓(ya)(ya)(ya)(ya)縮(suo)，在(zai)(zai)徑(jing)(jing)向(xiang)壓(ya)(ya)(ya)(ya)縮(suo)的(de)過(guo)(guo)程(cheng)中(zhong)金屬向(xiang)支(zhi)(zhi)管(guan)方(fang)向(xiang)流動并在(zai)(zai)沖模(mo)的(de)拉(la)伸下形(xing)(xing)成(cheng)(cheng)支(zhi)(zhi)管(guan)。整(zheng)個過(guo)(guo)程(cheng)是通(tong)過(guo)(guo)管(guan)坯(pi)的(de)徑(jing)(jing)向(xiang)壓(ya)(ya)(ya)(ya)縮(suo)和支(zhi)(zhi)管(guan)部位(wei)的(de)拉(la)伸過(guo)(guo)程(cheng)而成(cheng)(cheng)形(xing)(xing)。與液壓(ya)(ya)(ya)(ya)脹形(xing)(xing)三(san)(san)(san)通(tong)不同的(de)是，三(san)(san)(san)通(tong)接頭(tou)支(zhi)(zhi)管(guan)的(de)金屬是由管(guan)坯(pi)的(de)徑(jing)(jing)向(xiang)運動進行補(bu)償(chang)(chang)的(de)，所(suo)以也(ye)稱為(wei)徑(jing)(jing)向(xiang)補(bu)償(chang)(chang)工(gong)藝(yi)。由于采(cai)(cai)用加熱(re)后壓(ya)(ya)(ya)(ya)制三(san)(san)(san)通(tong)，材料成(cheng)(cheng)形(xing)(xing)所(suo)需要(yao)的(de)設備(bei)噸位(wei)降低。熱(re)壓(ya)(ya)(ya)(ya)三(san)(san)(san)通(tong)對(dui)材料的(de)適應性較寬，適用于低碳鋼、合金鋼、不銹鋼的(de)材料，特別是大直(zhi)徑(jing)(jing)和管(guan)壁偏(pian)厚的(de)三(san)(san)(san)通(tong)，通(tong)常采(cai)(cai)用這種成(cheng)(cheng)形(xing)(xing)工(gong)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)于異(yi)徑(jing)三(san)通(tong)(tong)(tong)，首先(xian)給(gei)出(chu)最(zui)(zui)大(da)(da)端(duan)(duan)(duan)(duan)的(de)(de)公(gong)稱(cheng)(cheng)(cheng)通(tong)(tong)(tong)徑(jing)，然后(hou)是與(yu)最(zui)(zui)大(da)(da)端(duan)(duan)(duan)(duan)相對(dui)應(ying)的(de)(de)那一(yi)端(duan)(duan)(duan)(duan)的(de)(de)公(gong)稱(cheng)(cheng)(cheng)通(tong)(tong)(tong)徑(jing)，最(zui)(zui)后(hou)給(gei)出(chu)支管端(duan)(duan)(duan)(duan)的(de)(de)公(gong)稱(cheng)(cheng)(cheng)通(tong)(tong)(tong)徑(jing)；對(dui)于異(yi)徑(jing)四通(tong)(tong)(tong)，首先(xian)給(gei)出(chu)最(zui)(zui)大(da)(da)端(duan)(duan)(duan)(duan)的(de)(de)公(gong)稱(cheng)(cheng)(cheng)通(tong)(tong)(tong)徑(jing)，其次(ci)是與(yu)最(zui)(zui)大(da)(da)端(duan)(duan)(duan)(duan)相對(dui)應(ying)的(de)(de)另(ling)一(yi)端(duan)(duan)(duan)(duan)的(de)(de)公(gong)稱(cheng)(cheng)(cheng)通(tong)(tong)(tong)徑(jing)，第三(san)個給(gei)出(chu)的(de)(de)是另(ling)外(wai)兩端(duan)(duan)(duan)(duan)中較大(da)(da)端(duan)(duan)(duan)(duan)的(de)(de)公(gong)稱(cheng)(cheng)(cheng)通(tong)(tong)(tong)徑(jing)，最(zui)(zui)后(hou)給(gei)出(chu)剩余一(yi)端(duan)(duan)(duan)(duan)的(de)(de)公(gong)稱(cheng)(cheng)(cheng)通(tong)(tong)(tong)徑(jing)，見(jian)圖16.27。
