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)按照管件口(kou)徑分(fen)一般有(you)等徑三(san)(san)(san)通(tong)(tong)［圖(tu)16.25（a）］、異(yi)徑三(san)(san)(san)通(tong)(tong)［圖(tu)16.25（b）］等。按照支管方向分(fen)有(you)正(zheng)三(san)(san)(san)通(tong)(tong)和斜三(san)(san)(san)通(tong)(tong)（y形三(san)(san)(san)通(tong)(tong)），斜三(san)(san)(san)通(tong)(tong)常(chang)常(chang)代(dai)替一般正(zheng)三(san)(san)(san)通(tong)(tong)，用于(yu)輸送有(you)固(gu)體顆粒或沖刷腐蝕較嚴重的管道上(shang)。按照材料分(fen)有(you)碳鋼、合金(jin)鋼、不銹鋼、銅、PVC等三(san)(san)(san)通(tong)(tong)。按照連接方式分(fen)有(you)普(pu)通(tong)(tong)三(san)(san)(san)通(tong)(tong)、螺紋三(san)(san)(san)通(tong)(tong)、卡(ka)套三(san)(san)(san)通(tong)(tong)、承插(cha)三(san)(san)(san)通(tong)(tong)。
③. 三(san)(san)通(tong)(tong)(tong)(tong)接(jie)頭(tou)成(cheng)形(xing)是(shi)(shi)(shi)將(jiang)大于三(san)(san)通(tong)(tong)(tong)(tong)直(zhi)徑(jing)(jing)的(de)(de)管(guan)坯(pi)，壓扁至約三(san)(san)通(tong)(tong)(tong)(tong)直(zhi)徑(jing)(jing)的(de)(de)尺(chi)寸，在(zai)(zai)拉伸支(zhi)(zhi)(zhi)管(guan)的(de)(de)部(bu)位(wei)開一個孔(kong)；管(guan)坯(pi)經加熱，放(fang)入成(cheng)形(xing)模(mo)中，并在(zai)(zai)管(guan)坯(pi)內裝入拉伸支(zhi)(zhi)(zhi)管(guan)的(de)(de)沖模(mo)；在(zai)(zai)壓力的(de)(de)作用下管(guan)坯(pi)被徑(jing)(jing)向(xiang)(xiang)(xiang)(xiang)壓縮，在(zai)(zai)徑(jing)(jing)向(xiang)(xiang)(xiang)(xiang)壓縮的(de)(de)過程(cheng)(cheng)中金(jin)屬向(xiang)(xiang)(xiang)(xiang)支(zhi)(zhi)(zhi)管(guan)方向(xiang)(xiang)(xiang)(xiang)流動并在(zai)(zai)沖模(mo)的(de)(de)拉伸下形(xing)成(cheng)支(zhi)(zhi)(zhi)管(guan)。整個過程(cheng)(cheng)是(shi)(shi)(shi)通(tong)(tong)(tong)(tong)過管(guan)坯(pi)的(de)(de)徑(jing)(jing)向(xiang)(xiang)(xiang)(xiang)壓縮和(he)支(zhi)(zhi)(zhi)管(guan)部(bu)位(wei)的(de)(de)拉伸過程(cheng)(cheng)而成(cheng)形(xing)。與液(ye)壓脹形(xing)三(san)(san)通(tong)(tong)(tong)(tong)不(bu)同的(de)(de)是(shi)(shi)(shi)，三(san)(san)通(tong)(tong)(tong)(tong)接(jie)頭(tou)支(zhi)(zhi)(zhi)管(guan)的(de)(de)金(jin)屬是(shi)(shi)(shi)由管(guan)坯(pi)的(de)(de)徑(jing)(jing)向(xiang)(xiang)(xiang)(xiang)運動進(jin)行補(bu)償(chang)的(de)(de)，所(suo)以也稱(cheng)為(wei)徑(jing)(jing)向(xiang)(xiang)(xiang)(xiang)補(bu)償(chang)工藝。由于采用加熱后壓制三(san)(san)通(tong)(tong)(tong)(tong)，材料成(cheng)形(xing)所(suo)需要的(de)(de)設備噸位(wei)降低(di)。熱壓三(san)(san)通(tong)(tong)(tong)(tong)對(dui)材料的(de)(de)適(shi)(shi)應性較(jiao)寬，適(shi)(shi)用于低(di)碳(tan)鋼、合金(jin)鋼、不(bu)銹鋼的(de)(de)材料，特別(bie)是(shi)(shi)(shi)大直(zhi)徑(jing)(jing)和(he)管(guan)壁偏(pian)厚的(de)(de)三(san)(san)通(tong)(tong)(tong)(tong)，通(tong)(tong)(tong)(tong)常采用這種(zhong)成(cheng)形(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、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(yu)異徑(jing)(jing)三通(tong)(tong)，首先給(gei)出(chu)(chu)最(zui)(zui)大端(duan)的(de)公(gong)(gong)稱(cheng)(cheng)(cheng)通(tong)(tong)徑(jing)(jing)，然后是(shi)與最(zui)(zui)大端(duan)相對(dui)(dui)(dui)應的(de)那一端(duan)的(de)公(gong)(gong)稱(cheng)(cheng)(cheng)通(tong)(tong)徑(jing)(jing)，最(zui)(zui)后給(gei)出(chu)(chu)支管端(duan)的(de)公(gong)(gong)稱(cheng)(cheng)(cheng)通(tong)(tong)徑(jing)(jing)；對(dui)(dui)(dui)于(yu)異徑(jing)(jing)四通(tong)(tong)，首先給(gei)出(chu)(chu)最(zui)(zui)大端(duan)的(de)公(gong)(gong)稱(cheng)(cheng)(cheng)通(tong)(tong)徑(jing)(jing)，其次是(shi)與最(zui)(zui)大端(duan)相對(dui)(dui)(dui)應的(de)另(ling)一端(duan)的(de)公(gong)(gong)稱(cheng)(cheng)(cheng)通(tong)(tong)徑(jing)(jing)，第(di)三個給(gei)出(chu)(chu)的(de)是(shi)另(ling)外兩(liang)端(duan)中較大端(duan)的(de)公(gong)(gong)稱(cheng)(cheng)(cheng)通(tong)(tong)徑(jing)(jing)，最(zui)(zui)后給(gei)出(chu)(chu)剩(sheng)余一端(duan)的(de)公(gong)(gong)稱(cheng)(cheng)(cheng)通(tong)(tong)徑(jing)(jing)，見圖16.27。
