①. 三通接頭是管件的一種，它的連接形式就是直接將三通(tong)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)(san)(san)(san)通(tong)(tong)按(an)(an)照(zhao)管件口徑(jing)分一般(ban)(ban)有(you)(you)等徑(jing)三(san)(san)(san)(san)(san)(san)(san)通(tong)(tong)［圖(tu)16.25（a）］、異徑(jing)三(san)(san)(san)(san)(san)(san)(san)通(tong)(tong)［圖(tu)16.25（b）］等。按(an)(an)照(zhao)支管方(fang)向分有(you)(you)正(zheng)三(san)(san)(san)(san)(san)(san)(san)通(tong)(tong)和斜三(san)(san)(san)(san)(san)(san)(san)通(tong)(tong)（y形(xing)三(san)(san)(san)(san)(san)(san)(san)通(tong)(tong)），斜三(san)(san)(san)(san)(san)(san)(san)通(tong)(tong)常常代替一般(ban)(ban)正(zheng)三(san)(san)(san)(san)(san)(san)(san)通(tong)(tong)，用于輸送有(you)(you)固體顆粒(li)或(huo)沖(chong)刷(shua)腐蝕較(jiao)嚴(yan)重的管道上。按(an)(an)照(zhao)材料分有(you)(you)碳鋼、合金鋼、不銹鋼、銅、PVC等三(san)(san)(san)(san)(san)(san)(san)通(tong)(tong)。按(an)(an)照(zhao)連接方(fang)式(shi)分有(you)(you)普通(tong)(tong)三(san)(san)(san)(san)(san)(san)(san)通(tong)(tong)、螺紋三(san)(san)(san)(san)(san)(san)(san)通(tong)(tong)、卡套三(san)(san)(san)(san)(san)(san)(san)通(tong)(tong)、承插三(san)(san)(san)(san)(san)(san)(san)通(tong)(tong)。
③. 三(san)(san)通(tong)(tong)接頭成形是(shi)將(jiang)大于三(san)(san)通(tong)(tong)直(zhi)徑(jing)(jing)(jing)的(de)(de)(de)(de)管(guan)(guan)(guan)(guan)坯(pi)(pi)(pi)，壓扁至(zhi)約三(san)(san)通(tong)(tong)直(zhi)徑(jing)(jing)(jing)的(de)(de)(de)(de)尺寸，在(zai)(zai)拉伸支管(guan)(guan)(guan)(guan)的(de)(de)(de)(de)部位開一(yi)個孔；管(guan)(guan)(guan)(guan)坯(pi)(pi)(pi)經加(jia)熱，放入成形模(mo)中，并在(zai)(zai)管(guan)(guan)(guan)(guan)坯(pi)(pi)(pi)內裝入拉伸支管(guan)(guan)(guan)(guan)的(de)(de)(de)(de)沖模(mo)；在(zai)(zai)壓力的(de)(de)(de)(de)作用(yong)下(xia)管(guan)(guan)(guan)(guan)坯(pi)(pi)(pi)被徑(jing)(jing)(jing)向(xiang)(xiang)(xiang)壓縮，在(zai)(zai)徑(jing)(jing)(jing)向(xiang)(xiang)(xiang)壓縮的(de)(de)(de)(de)過(guo)程中金屬(shu)向(xiang)(xiang)(xiang)支管(guan)(guan)(guan)(guan)方向(xiang)(xiang)(xiang)流動(dong)并在(zai)(zai)沖模(mo)的(de)(de)(de)(de)拉伸下(xia)形成支管(guan)(guan)(guan)(guan)。整個過(guo)程是(shi)通(tong)(tong)過(guo)管(guan)(guan)(guan)(guan)坯(pi)(pi)(pi)的(de)(de)(de)(de)徑(jing)(jing)(jing)向(xiang)(xiang)(xiang)壓縮和(he)支管(guan)(guan)(guan)(guan)部位的(de)(de)(de)(de)拉伸過(guo)程而(er)成形。與(yu)液(ye)壓脹形三(san)(san)通(tong)(tong)不同(tong)的(de)(de)(de)(de)是(shi)，三(san)(san)通(tong)(tong)接頭支管(guan)(guan)(guan)(guan)的(de)(de)(de)(de)金屬(shu)是(shi)由管(guan)(guan)(guan)(guan)坯(pi)(pi)(pi)的(de)(de)(de)(de)徑(jing)(jing)(jing)向(xiang)(xiang)(xiang)運動(dong)進行補償(chang)的(de)(de)(de)(de)，所以(yi)也稱(cheng)為徑(jing)(jing)(jing)向(xiang)(xiang)(xiang)補償(chang)工(gong)藝(yi)。由于采(cai)用(yong)加(jia)熱后壓制(zhi)三(san)(san)通(tong)(tong)，材料(liao)成形所需要(yao)的(de)(de)(de)(de)設備噸位降(jiang)低(di)。熱壓三(san)(san)通(tong)(tong)對(dui)材料(liao)的(de)(de)(de)(de)適(shi)應性較(jiao)寬，適(shi)用(yong)于低(di)碳(tan)鋼(gang)(gang)、合金鋼(gang)(gang)、不銹鋼(gang)(gang)的(de)(de)(de)(de)材料(liao)，特(te)別是(shi)大直(zhi)徑(jing)(jing)(jing)和(he)管(guan)(guan)(guan)(guan)壁偏厚的(de)(de)(de)(de)三(san)(san)通(tong)(tong)，通(tong)(tong)常采(cai)用(yong)這(zhe)種成形工(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)(dui)(dui)于異徑(jing)三通(tong)(tong)，首先給(gei)出(chu)(chu)(chu)最大(da)(da)端(duan)(duan)(duan)(duan)的(de)公(gong)(gong)稱通(tong)(tong)徑(jing)，然后是(shi)與(yu)最大(da)(da)端(duan)(duan)(duan)(duan)相對(dui)(dui)(dui)應的(de)那一端(duan)(duan)(duan)(duan)的(de)公(gong)(gong)稱通(tong)(tong)徑(jing)，最后給(gei)出(chu)(chu)(chu)支管(guan)端(duan)(duan)(duan)(duan)的(de)公(gong)(gong)稱通(tong)(tong)徑(jing)；對(dui)(dui)(dui)于異徑(jing)四通(tong)(tong)，首先給(gei)出(chu)(chu)(chu)最大(da)(da)端(duan)(duan)(duan)(duan)的(de)公(gong)(gong)稱通(tong)(tong)徑(jing)，其次是(shi)與(yu)最大(da)(da)端(duan)(duan)(duan)(duan)相對(dui)(dui)(dui)應的(de)另(ling)一端(duan)(duan)(duan)(duan)的(de)公(gong)(gong)稱通(tong)(tong)徑(jing)，第三個給(gei)出(chu)(chu)(chu)的(de)是(shi)另(ling)外兩(liang)端(duan)(duan)(duan)(duan)中較大(da)(da)端(duan)(duan)(duan)(duan)的(de)公(gong)(gong)稱通(tong)(tong)徑(jing)，最后給(gei)出(chu)(chu)(chu)剩(sheng)余一端(duan)(duan)(duan)(duan)的(de)公(gong)(gong)稱通(tong)(tong)徑(jing)，見圖(tu)16.27。
