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)照(zhao)管件口徑(jing)分(fen)一般(ban)有(you)等(deng)徑(jing)三(san)(san)通(tong)(tong)(tong)(tong)［圖(tu)16.25（a）］、異徑(jing)三(san)(san)通(tong)(tong)(tong)(tong)［圖(tu)16.25（b）］等(deng)。按(an)照(zhao)支管方向(xiang)分(fen)有(you)正(zheng)(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(dai)替一般(ban)正(zheng)(zheng)三(san)(san)通(tong)(tong)(tong)(tong)，用于輸送有(you)固體(ti)顆粒或沖(chong)刷腐蝕較嚴重(zhong)的管道上。按(an)照(zhao)材(cai)料分(fen)有(you)碳鋼(gang)、合金鋼(gang)、不銹鋼(gang)、銅、PVC等(deng)三(san)(san)通(tong)(tong)(tong)(tong)。按(an)照(zhao)連接方式分(fen)有(you)普(pu)通(tong)(tong)(tong)(tong)三(san)(san)通(tong)(tong)(tong)(tong)、螺紋三(san)(san)通(tong)(tong)(tong)(tong)、卡套三(san)(san)通(tong)(tong)(tong)(tong)、承插(cha)三(san)(san)通(tong)(tong)(tong)(tong)。
③. 三(san)通(tong)(tong)(tong)接(jie)頭(tou)成(cheng)(cheng)(cheng)形(xing)(xing)是(shi)(shi)將大于(yu)三(san)通(tong)(tong)(tong)直(zhi)徑(jing)(jing)(jing)的(de)(de)(de)管(guan)(guan)坯(pi)(pi)(pi)(pi)，壓扁至約三(san)通(tong)(tong)(tong)直(zhi)徑(jing)(jing)(jing)的(de)(de)(de)尺寸，在(zai)(zai)拉伸(shen)支(zhi)管(guan)(guan)的(de)(de)(de)部(bu)位(wei)開一個孔(kong)；管(guan)(guan)坯(pi)(pi)(pi)(pi)經加熱(re)，放(fang)入(ru)成(cheng)(cheng)(cheng)形(xing)(xing)模(mo)中(zhong)，并在(zai)(zai)管(guan)(guan)坯(pi)(pi)(pi)(pi)內裝入(ru)拉伸(shen)支(zhi)管(guan)(guan)的(de)(de)(de)沖模(mo)；在(zai)(zai)壓力的(de)(de)(de)作用(yong)下管(guan)(guan)坯(pi)(pi)(pi)(pi)被徑(jing)(jing)(jing)向(xiang)壓縮(suo)，在(zai)(zai)徑(jing)(jing)(jing)向(xiang)壓縮(suo)的(de)(de)(de)過程(cheng)中(zhong)金(jin)屬向(xiang)支(zhi)管(guan)(guan)方(fang)向(xiang)流(liu)動并在(zai)(zai)沖模(mo)的(de)(de)(de)拉伸(shen)下形(xing)(xing)成(cheng)(cheng)(cheng)支(zhi)管(guan)(guan)。整個過程(cheng)是(shi)(shi)通(tong)(tong)(tong)過管(guan)(guan)坯(pi)(pi)(pi)(pi)的(de)(de)(de)徑(jing)(jing)(jing)向(xiang)壓縮(suo)和(he)(he)支(zhi)管(guan)(guan)部(bu)位(wei)的(de)(de)(de)拉伸(shen)過程(cheng)而成(cheng)(cheng)(cheng)形(xing)(xing)。與(yu)液壓脹(zhang)形(xing)(xing)三(san)通(tong)(tong)(tong)不同的(de)(de)(de)是(shi)(shi)，三(san)通(tong)(tong)(tong)接(jie)頭(tou)支(zhi)管(guan)(guan)的(de)(de)(de)金(jin)屬是(shi)(shi)由(you)管(guan)(guan)坯(pi)(pi)(pi)(pi)的(de)(de)(de)徑(jing)(jing)(jing)向(xiang)運動進行(xing)補償(chang)的(de)(de)(de)，所以也稱為徑(jing)(jing)(jing)向(xiang)補償(chang)工藝。由(you)于(yu)采用(yong)加熱(re)后壓制三(san)通(tong)(tong)(tong)，材(cai)(cai)料(liao)成(cheng)(cheng)(cheng)形(xing)(xing)所需要的(de)(de)(de)設備(bei)噸位(wei)降低。熱(re)壓三(san)通(tong)(tong)(tong)對材(cai)(cai)料(liao)的(de)(de)(de)適應性(xing)較(jiao)寬，適用(yong)于(yu)低碳鋼、合(he)金(jin)鋼、不銹鋼的(de)(de)(de)材(cai)(cai)料(liao)，特別是(shi)(shi)大直(zhi)徑(jing)(jing)(jing)和(he)(he)管(guan)(guan)壁(bi)偏厚的(de)(de)(de)三(san)通(tong)(tong)(tong)，通(tong)(tong)(tong)常采用(yong)這種成(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)于異徑(jing)三(san)通，首先給(gei)(gei)出(chu)(chu)最(zui)大(da)(da)端(duan)(duan)的(de)(de)公(gong)(gong)稱(cheng)(cheng)通徑(jing)，然后是(shi)與最(zui)大(da)(da)端(duan)(duan)相對(dui)應(ying)的(de)(de)那(nei)一端(duan)(duan)的(de)(de)公(gong)(gong)稱(cheng)(cheng)通徑(jing)，最(zui)后給(gei)(gei)出(chu)(chu)支(zhi)管(guan)端(duan)(duan)的(de)(de)公(gong)(gong)稱(cheng)(cheng)通徑(jing)；對(dui)于異徑(jing)四(si)通，首先給(gei)(gei)出(chu)(chu)最(zui)大(da)(da)端(duan)(duan)的(de)(de)公(gong)(gong)稱(cheng)(cheng)通徑(jing)，其次(ci)是(shi)與最(zui)大(da)(da)端(duan)(duan)相對(dui)應(ying)的(de)(de)另(ling)一端(duan)(duan)的(de)(de)公(gong)(gong)稱(cheng)(cheng)通徑(jing)，第(di)三(san)個給(gei)(gei)出(chu)(chu)的(de)(de)是(shi)另(ling)外兩端(duan)(duan)中(zhong)較(jiao)大(da)(da)端(duan)(duan)的(de)(de)公(gong)(gong)稱(cheng)(cheng)通徑(jing)，最(zui)后給(gei)(gei)出(chu)(chu)剩余一端(duan)(duan)的(de)(de)公(gong)(gong)稱(cheng)(cheng)通徑(jing)，見圖16.27。
