①. 三通接頭是管件的一種，它的連接形式就是直接將三(san)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. 三通(tong)(tong)按(an)(an)照(zhao)管(guan)件口徑(jing)分一(yi)般有等徑(jing)三通(tong)(tong)［圖16.25（a）］、異徑(jing)三通(tong)(tong)［圖16.25（b）］等。按(an)(an)照(zhao)支管(guan)方向分有正三通(tong)(tong)和斜三通(tong)(tong)（y形三通(tong)(tong)），斜三通(tong)(tong)常常代替一(yi)般正三通(tong)(tong)，用于輸(shu)送有固體顆粒(li)或沖刷(shua)腐蝕(shi)較嚴重的管(guan)道上。按(an)(an)照(zhao)材料分有碳鋼、合(he)金鋼、不(bu)銹鋼、銅、PVC等三通(tong)(tong)。按(an)(an)照(zhao)連接(jie)方式分有普通(tong)(tong)三通(tong)(tong)、螺(luo)紋三通(tong)(tong)、卡套三通(tong)(tong)、承插(cha)三通(tong)(tong)。
③. 三(san)(san)(san)通(tong)接(jie)頭(tou)成形(xing)(xing)是(shi)(shi)將大(da)于(yu)三(san)(san)(san)通(tong)直(zhi)(zhi)徑(jing)(jing)(jing)的(de)(de)管(guan)(guan)坯(pi)(pi)，壓(ya)扁至約三(san)(san)(san)通(tong)直(zhi)(zhi)徑(jing)(jing)(jing)的(de)(de)尺寸，在(zai)(zai)(zai)拉(la)伸(shen)支(zhi)(zhi)管(guan)(guan)的(de)(de)部(bu)位開一個(ge)孔；管(guan)(guan)坯(pi)(pi)經加(jia)熱，放(fang)入(ru)成形(xing)(xing)模(mo)中，并在(zai)(zai)(zai)管(guan)(guan)坯(pi)(pi)內裝入(ru)拉(la)伸(shen)支(zhi)(zhi)管(guan)(guan)的(de)(de)沖(chong)模(mo)；在(zai)(zai)(zai)壓(ya)力的(de)(de)作用(yong)下(xia)管(guan)(guan)坯(pi)(pi)被徑(jing)(jing)(jing)向(xiang)(xiang)壓(ya)縮，在(zai)(zai)(zai)徑(jing)(jing)(jing)向(xiang)(xiang)壓(ya)縮的(de)(de)過(guo)程中金屬向(xiang)(xiang)支(zhi)(zhi)管(guan)(guan)方(fang)向(xiang)(xiang)流動并在(zai)(zai)(zai)沖(chong)模(mo)的(de)(de)拉(la)伸(shen)下(xia)形(xing)(xing)成支(zhi)(zhi)管(guan)(guan)。整個(ge)過(guo)程是(shi)(shi)通(tong)過(guo)管(guan)(guan)坯(pi)(pi)的(de)(de)徑(jing)(jing)(jing)向(xiang)(xiang)壓(ya)縮和(he)支(zhi)(zhi)管(guan)(guan)部(bu)位的(de)(de)拉(la)伸(shen)過(guo)程而成形(xing)(xing)。與液壓(ya)脹形(xing)(xing)三(san)(san)(san)通(tong)不(bu)同的(de)(de)是(shi)(shi)，三(san)(san)(san)通(tong)接(jie)頭(tou)支(zhi)(zhi)管(guan)(guan)的(de)(de)金屬是(shi)(shi)由管(guan)(guan)坯(pi)(pi)的(de)(de)徑(jing)(jing)(jing)向(xiang)(xiang)運動進行補償的(de)(de)，所以(yi)也稱為徑(jing)(jing)(jing)向(xiang)(xiang)補償工藝。由于(yu)采(cai)用(yong)加(jia)熱后(hou)壓(ya)制三(san)(san)(san)通(tong)，材料成形(xing)(xing)所需要的(de)(de)設備(bei)噸(dun)位降(jiang)低。熱壓(ya)三(san)(san)(san)通(tong)對材料的(de)(de)適應(ying)性較(jiao)寬，適用(yong)于(yu)低碳鋼(gang)、合(he)金鋼(gang)、不(bu)銹鋼(gang)的(de)(de)材料，特別是(shi)(shi)大(da)直(zhi)(zhi)徑(jing)(jing)(jing)和(he)管(guan)(guan)壁(bi)偏厚(hou)的(de)(de)三(san)(san)(san)通(tong)，通(tong)常采(cai)用(yong)這(zhe)種成形(xing)(xing)工藝。
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(tong)、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)(dui)于(yu)異徑(jing)三(san)(san)通(tong)，首先(xian)給(gei)(gei)出(chu)最(zui)(zui)(zui)大端(duan)(duan)(duan)(duan)(duan)的(de)(de)(de)(de)公(gong)(gong)(gong)(gong)稱(cheng)(cheng)通(tong)徑(jing)，然后(hou)是與最(zui)(zui)(zui)大端(duan)(duan)(duan)(duan)(duan)相(xiang)對(dui)(dui)應的(de)(de)(de)(de)那一端(duan)(duan)(duan)(duan)(duan)的(de)(de)(de)(de)公(gong)(gong)(gong)(gong)稱(cheng)(cheng)通(tong)徑(jing)，最(zui)(zui)(zui)后(hou)給(gei)(gei)出(chu)支(zhi)管端(duan)(duan)(duan)(duan)(duan)的(de)(de)(de)(de)公(gong)(gong)(gong)(gong)稱(cheng)(cheng)通(tong)徑(jing)；對(dui)(dui)于(yu)異徑(jing)四通(tong)，首先(xian)給(gei)(gei)出(chu)最(zui)(zui)(zui)大端(duan)(duan)(duan)(duan)(duan)的(de)(de)(de)(de)公(gong)(gong)(gong)(gong)稱(cheng)(cheng)通(tong)徑(jing)，其(qi)次是與最(zui)(zui)(zui)大端(duan)(duan)(duan)(duan)(duan)相(xiang)對(dui)(dui)應的(de)(de)(de)(de)另(ling)一端(duan)(duan)(duan)(duan)(duan)的(de)(de)(de)(de)公(gong)(gong)(gong)(gong)稱(cheng)(cheng)通(tong)徑(jing)，第三(san)(san)個(ge)給(gei)(gei)出(chu)的(de)(de)(de)(de)是另(ling)外(wai)兩端(duan)(duan)(duan)(duan)(duan)中較大端(duan)(duan)(duan)(duan)(duan)的(de)(de)(de)(de)公(gong)(gong)(gong)(gong)稱(cheng)(cheng)通(tong)徑(jing)，最(zui)(zui)(zui)后(hou)給(gei)(gei)出(chu)剩(sheng)余一端(duan)(duan)(duan)(duan)(duan)的(de)(de)(de)(de)公(gong)(gong)(gong)(gong)稱(cheng)(cheng)通(tong)徑(jing)，見圖16.27。
