①. 三通接頭是管件(jian)的一種，它的連接形式就是直接將三(san)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)通(tong)(tong)(tong)(tong)按(an)(an)(an)照(zhao)管(guan)件口(kou)徑(jing)分一般(ban)有(you)等徑(jing)三(san)(san)通(tong)(tong)(tong)(tong)［圖16.25（a）］、異徑(jing)三(san)(san)通(tong)(tong)(tong)(tong)［圖16.25（b）］等。按(an)(an)(an)照(zhao)支管(guan)方向分有(you)正(zheng)三(san)(san)通(tong)(tong)(tong)(tong)和斜(xie)三(san)(san)通(tong)(tong)(tong)(tong)（y形三(san)(san)通(tong)(tong)(tong)(tong)），斜(xie)三(san)(san)通(tong)(tong)(tong)(tong)常常代替一般(ban)正(zheng)三(san)(san)通(tong)(tong)(tong)(tong)，用于輸送有(you)固體顆(ke)粒或沖刷腐蝕(shi)較嚴重的管(guan)道上。按(an)(an)(an)照(zhao)材料分有(you)碳鋼(gang)、合金(jin)鋼(gang)、不(bu)銹(xiu)鋼(gang)、銅、PVC等三(san)(san)通(tong)(tong)(tong)(tong)。按(an)(an)(an)照(zhao)連(lian)接(jie)方式分有(you)普通(tong)(tong)(tong)(tong)三(san)(san)通(tong)(tong)(tong)(tong)、螺紋三(san)(san)通(tong)(tong)(tong)(tong)、卡(ka)套(tao)三(san)(san)通(tong)(tong)(tong)(tong)、承插三(san)(san)通(tong)(tong)(tong)(tong)。
③. 三(san)(san)通(tong)(tong)(tong)(tong)接(jie)頭成(cheng)形(xing)(xing)是(shi)將大(da)于三(san)(san)通(tong)(tong)(tong)(tong)直(zhi)徑(jing)的(de)(de)管(guan)(guan)坯(pi)，壓(ya)(ya)扁至(zhi)約三(san)(san)通(tong)(tong)(tong)(tong)直(zhi)徑(jing)的(de)(de)尺寸，在(zai)(zai)拉伸支(zhi)管(guan)(guan)的(de)(de)部位開一(yi)個(ge)孔；管(guan)(guan)坯(pi)經(jing)加熱(re)，放入成(cheng)形(xing)(xing)模中，并(bing)在(zai)(zai)管(guan)(guan)坯(pi)內裝入拉伸支(zhi)管(guan)(guan)的(de)(de)沖(chong)模；在(zai)(zai)壓(ya)(ya)力的(de)(de)作用(yong)(yong)下管(guan)(guan)坯(pi)被徑(jing)向(xiang)(xiang)(xiang)(xiang)壓(ya)(ya)縮(suo)，在(zai)(zai)徑(jing)向(xiang)(xiang)(xiang)(xiang)壓(ya)(ya)縮(suo)的(de)(de)過(guo)程(cheng)中金屬(shu)向(xiang)(xiang)(xiang)(xiang)支(zhi)管(guan)(guan)方向(xiang)(xiang)(xiang)(xiang)流動(dong)并(bing)在(zai)(zai)沖(chong)模的(de)(de)拉伸下形(xing)(xing)成(cheng)支(zhi)管(guan)(guan)。整個(ge)過(guo)程(cheng)是(shi)通(tong)(tong)(tong)(tong)過(guo)管(guan)(guan)坯(pi)的(de)(de)徑(jing)向(xiang)(xiang)(xiang)(xiang)壓(ya)(ya)縮(suo)和支(zhi)管(guan)(guan)部位的(de)(de)拉伸過(guo)程(cheng)而成(cheng)形(xing)(xing)。與(yu)液壓(ya)(ya)脹形(xing)(xing)三(san)(san)通(tong)(tong)(tong)(tong)不同的(de)(de)是(shi)，三(san)(san)通(tong)(tong)(tong)(tong)接(jie)頭支(zhi)管(guan)(guan)的(de)(de)金屬(shu)是(shi)由(you)管(guan)(guan)坯(pi)的(de)(de)徑(jing)向(xiang)(xiang)(xiang)(xiang)運動(dong)進行補償(chang)的(de)(de)，所以也稱為徑(jing)向(xiang)(xiang)(xiang)(xiang)補償(chang)工(gong)藝。由(you)于采用(yong)(yong)加熱(re)后壓(ya)(ya)制三(san)(san)通(tong)(tong)(tong)(tong)，材(cai)料(liao)成(cheng)形(xing)(xing)所需要(yao)的(de)(de)設備噸位降(jiang)低(di)。熱(re)壓(ya)(ya)三(san)(san)通(tong)(tong)(tong)(tong)對材(cai)料(liao)的(de)(de)適(shi)應性(xing)較(jiao)寬(kuan)，適(shi)用(yong)(yong)于低(di)碳鋼(gang)、合金鋼(gang)、不銹鋼(gang)的(de)(de)材(cai)料(liao)，特別是(shi)大(da)直(zhi)徑(jing)和管(guan)(guan)壁偏(pian)厚(hou)的(de)(de)三(san)(san)通(tong)(tong)(tong)(tong)，通(tong)(tong)(tong)(tong)常采用(yong)(yong)這種(zhong)成(cheng)形(xing)(xing)工(gong)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(yi)徑(jing)(jing)三通(tong)(tong)(tong)(tong)，首(shou)先給(gei)出(chu)最(zui)大端(duan)(duan)(duan)(duan)的(de)(de)(de)公(gong)稱通(tong)(tong)(tong)(tong)徑(jing)(jing)，然后是與(yu)最(zui)大端(duan)(duan)(duan)(duan)相(xiang)(xiang)對(dui)應的(de)(de)(de)那(nei)一(yi)端(duan)(duan)(duan)(duan)的(de)(de)(de)公(gong)稱通(tong)(tong)(tong)(tong)徑(jing)(jing)，最(zui)后給(gei)出(chu)支管端(duan)(duan)(duan)(duan)的(de)(de)(de)公(gong)稱通(tong)(tong)(tong)(tong)徑(jing)(jing)；對(dui)于(yu)異(yi)徑(jing)(jing)四通(tong)(tong)(tong)(tong)，首(shou)先給(gei)出(chu)最(zui)大端(duan)(duan)(duan)(duan)的(de)(de)(de)公(gong)稱通(tong)(tong)(tong)(tong)徑(jing)(jing)，其次是與(yu)最(zui)大端(duan)(duan)(duan)(duan)相(xiang)(xiang)對(dui)應的(de)(de)(de)另一(yi)端(duan)(duan)(duan)(duan)的(de)(de)(de)公(gong)稱通(tong)(tong)(tong)(tong)徑(jing)(jing)，第三個給(gei)出(chu)的(de)(de)(de)是另外兩端(duan)(duan)(duan)(duan)中較(jiao)大端(duan)(duan)(duan)(duan)的(de)(de)(de)公(gong)稱通(tong)(tong)(tong)(tong)徑(jing)(jing)，最(zui)后給(gei)出(chu)剩余一(yi)端(duan)(duan)(duan)(duan)的(de)(de)(de)公(gong)稱通(tong)(tong)(tong)(tong)徑(jing)(jing)，見圖16.27。
