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(san)(san)(san)通(tong)(tong)按(an)照(zhao)管(guan)件口徑(jing)分一(yi)般(ban)有等徑(jing)三(san)(san)(san)通(tong)(tong)［圖(tu)16.25（a）］、異徑(jing)三(san)(san)(san)通(tong)(tong)［圖(tu)16.25（b）］等。按(an)照(zhao)支管(guan)方向分有正三(san)(san)(san)通(tong)(tong)和斜三(san)(san)(san)通(tong)(tong)（y形(xing)三(san)(san)(san)通(tong)(tong)），斜三(san)(san)(san)通(tong)(tong)常常代替(ti)一(yi)般(ban)正三(san)(san)(san)通(tong)(tong)，用于(yu)輸(shu)送有固體顆粒或(huo)沖(chong)刷腐(fu)蝕較(jiao)嚴重的管(guan)道上。按(an)照(zhao)材料分有碳(tan)鋼、合(he)金鋼、不銹(xiu)鋼、銅、PVC等三(san)(san)(san)通(tong)(tong)。按(an)照(zhao)連(lian)接(jie)方式分有普通(tong)(tong)三(san)(san)(san)通(tong)(tong)、螺紋(wen)三(san)(san)(san)通(tong)(tong)、卡套三(san)(san)(san)通(tong)(tong)、承(cheng)插三(san)(san)(san)通(tong)(tong)。
③. 三(san)(san)通(tong)(tong)(tong)(tong)接頭成(cheng)(cheng)(cheng)形(xing)(xing)是(shi)(shi)將(jiang)大(da)于(yu)三(san)(san)通(tong)(tong)(tong)(tong)直徑(jing)(jing)(jing)的(de)(de)(de)(de)管(guan)(guan)(guan)(guan)坯(pi)，壓扁至約三(san)(san)通(tong)(tong)(tong)(tong)直徑(jing)(jing)(jing)的(de)(de)(de)(de)尺(chi)寸，在拉(la)伸支(zhi)(zhi)管(guan)(guan)(guan)(guan)的(de)(de)(de)(de)部位開一個(ge)孔；管(guan)(guan)(guan)(guan)坯(pi)經加熱(re)，放入成(cheng)(cheng)(cheng)形(xing)(xing)模中，并在管(guan)(guan)(guan)(guan)坯(pi)內裝入拉(la)伸支(zhi)(zhi)管(guan)(guan)(guan)(guan)的(de)(de)(de)(de)沖模；在壓力的(de)(de)(de)(de)作用(yong)下管(guan)(guan)(guan)(guan)坯(pi)被徑(jing)(jing)(jing)向(xiang)壓縮(suo)(suo)，在徑(jing)(jing)(jing)向(xiang)壓縮(suo)(suo)的(de)(de)(de)(de)過程(cheng)中金(jin)屬向(xiang)支(zhi)(zhi)管(guan)(guan)(guan)(guan)方向(xiang)流動并在沖模的(de)(de)(de)(de)拉(la)伸下形(xing)(xing)成(cheng)(cheng)(cheng)支(zhi)(zhi)管(guan)(guan)(guan)(guan)。整(zheng)個(ge)過程(cheng)是(shi)(shi)通(tong)(tong)(tong)(tong)過管(guan)(guan)(guan)(guan)坯(pi)的(de)(de)(de)(de)徑(jing)(jing)(jing)向(xiang)壓縮(suo)(suo)和支(zhi)(zhi)管(guan)(guan)(guan)(guan)部位的(de)(de)(de)(de)拉(la)伸過程(cheng)而成(cheng)(cheng)(cheng)形(xing)(xing)。與(yu)液壓脹形(xing)(xing)三(san)(san)通(tong)(tong)(tong)(tong)不(bu)同的(de)(de)(de)(de)是(shi)(shi)，三(san)(san)通(tong)(tong)(tong)(tong)接頭支(zhi)(zhi)管(guan)(guan)(guan)(guan)的(de)(de)(de)(de)金(jin)屬是(shi)(shi)由(you)管(guan)(guan)(guan)(guan)坯(pi)的(de)(de)(de)(de)徑(jing)(jing)(jing)向(xiang)運動進行補(bu)償的(de)(de)(de)(de)，所以也稱為徑(jing)(jing)(jing)向(xiang)補(bu)償工藝。由(you)于(yu)采用(yong)加熱(re)后壓制三(san)(san)通(tong)(tong)(tong)(tong)，材(cai)料(liao)成(cheng)(cheng)(cheng)形(xing)(xing)所需(xu)要的(de)(de)(de)(de)設備噸位降(jiang)低(di)。熱(re)壓三(san)(san)通(tong)(tong)(tong)(tong)對材(cai)料(liao)的(de)(de)(de)(de)適應性較寬，適用(yong)于(yu)低(di)碳(tan)鋼、合(he)金(jin)鋼、不(bu)銹(xiu)鋼的(de)(de)(de)(de)材(cai)料(liao)，特(te)別是(shi)(shi)大(da)直徑(jing)(jing)(jing)和管(guan)(guan)(guan)(guan)壁偏(pian)厚的(de)(de)(de)(de)三(san)(san)通(tong)(tong)(tong)(tong)，通(tong)(tong)(tong)(tong)常采用(yong)這種(zhong)成(cheng)(cheng)(cheng)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)于(yu)異徑(jing)(jing)(jing)(jing)三通(tong)(tong)，首先給(gei)出最大(da)(da)端(duan)(duan)的(de)(de)公稱通(tong)(tong)徑(jing)(jing)(jing)(jing)，然后是與(yu)最大(da)(da)端(duan)(duan)相對(dui)應(ying)的(de)(de)那一(yi)端(duan)(duan)的(de)(de)公稱通(tong)(tong)徑(jing)(jing)(jing)(jing)，最后給(gei)出支管端(duan)(duan)的(de)(de)公稱通(tong)(tong)徑(jing)(jing)(jing)(jing)；對(dui)于(yu)異徑(jing)(jing)(jing)(jing)四通(tong)(tong)，首先給(gei)出最大(da)(da)端(duan)(duan)的(de)(de)公稱通(tong)(tong)徑(jing)(jing)(jing)(jing)，其(qi)次是與(yu)最大(da)(da)端(duan)(duan)相對(dui)應(ying)的(de)(de)另(ling)一(yi)端(duan)(duan)的(de)(de)公稱通(tong)(tong)徑(jing)(jing)(jing)(jing)，第三個給(gei)出的(de)(de)是另(ling)外兩(liang)端(duan)(duan)中較大(da)(da)端(duan)(duan)的(de)(de)公稱通(tong)(tong)徑(jing)(jing)(jing)(jing)，最后給(gei)出剩(sheng)余一(yi)端(duan)(duan)的(de)(de)公稱通(tong)(tong)徑(jing)(jing)(jing)(jing)，見圖16.27。
