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)通(tong)(tong)(tong)(tong)(tong)按(an)照(zhao)管件口徑分一(yi)般(ban)有(you)(you)等徑三(san)通(tong)(tong)(tong)(tong)(tong)［圖(tu)16.25（a）］、異徑三(san)通(tong)(tong)(tong)(tong)(tong)［圖(tu)16.25（b）］等。按(an)照(zhao)支管方向分有(you)(you)正三(san)通(tong)(tong)(tong)(tong)(tong)和斜(xie)三(san)通(tong)(tong)(tong)(tong)(tong)（y形(xing)三(san)通(tong)(tong)(tong)(tong)(tong)），斜(xie)三(san)通(tong)(tong)(tong)(tong)(tong)常(chang)常(chang)代替一(yi)般(ban)正三(san)通(tong)(tong)(tong)(tong)(tong)，用于輸送有(you)(you)固體顆粒或(huo)沖刷腐蝕較嚴重的管道上(shang)。按(an)照(zhao)材料分有(you)(you)碳鋼(gang)、合金鋼(gang)、不銹鋼(gang)、銅、PVC等三(san)通(tong)(tong)(tong)(tong)(tong)。按(an)照(zhao)連接(jie)方式(shi)分有(you)(you)普通(tong)(tong)(tong)(tong)(tong)三(san)通(tong)(tong)(tong)(tong)(tong)、螺紋三(san)通(tong)(tong)(tong)(tong)(tong)、卡套三(san)通(tong)(tong)(tong)(tong)(tong)、承插三(san)通(tong)(tong)(tong)(tong)(tong)。
③. 三(san)(san)通(tong)(tong)接頭成(cheng)(cheng)形(xing)(xing)是將大(da)于(yu)(yu)三(san)(san)通(tong)(tong)直(zhi)徑(jing)(jing)的(de)(de)(de)(de)管(guan)坯(pi)，壓(ya)扁(bian)至約三(san)(san)通(tong)(tong)直(zhi)徑(jing)(jing)的(de)(de)(de)(de)尺寸，在(zai)拉(la)伸(shen)(shen)支(zhi)管(guan)的(de)(de)(de)(de)部(bu)位(wei)(wei)開一個孔(kong)；管(guan)坯(pi)經加熱，放入(ru)成(cheng)(cheng)形(xing)(xing)模中，并在(zai)管(guan)坯(pi)內裝入(ru)拉(la)伸(shen)(shen)支(zhi)管(guan)的(de)(de)(de)(de)沖(chong)模；在(zai)壓(ya)力的(de)(de)(de)(de)作用(yong)下管(guan)坯(pi)被徑(jing)(jing)向(xiang)(xiang)壓(ya)縮，在(zai)徑(jing)(jing)向(xiang)(xiang)壓(ya)縮的(de)(de)(de)(de)過程中金(jin)屬向(xiang)(xiang)支(zhi)管(guan)方向(xiang)(xiang)流(liu)動(dong)并在(zai)沖(chong)模的(de)(de)(de)(de)拉(la)伸(shen)(shen)下形(xing)(xing)成(cheng)(cheng)支(zhi)管(guan)。整(zheng)個過程是通(tong)(tong)過管(guan)坯(pi)的(de)(de)(de)(de)徑(jing)(jing)向(xiang)(xiang)壓(ya)縮和支(zhi)管(guan)部(bu)位(wei)(wei)的(de)(de)(de)(de)拉(la)伸(shen)(shen)過程而(er)成(cheng)(cheng)形(xing)(xing)。與液壓(ya)脹形(xing)(xing)三(san)(san)通(tong)(tong)不(bu)同的(de)(de)(de)(de)是，三(san)(san)通(tong)(tong)接頭支(zhi)管(guan)的(de)(de)(de)(de)金(jin)屬是由(you)管(guan)坯(pi)的(de)(de)(de)(de)徑(jing)(jing)向(xiang)(xiang)運(yun)動(dong)進(jin)行補(bu)償的(de)(de)(de)(de)，所(suo)以也稱(cheng)為徑(jing)(jing)向(xiang)(xiang)補(bu)償工(gong)藝(yi)。由(you)于(yu)(yu)采用(yong)加熱后壓(ya)制三(san)(san)通(tong)(tong)，材(cai)(cai)料(liao)成(cheng)(cheng)形(xing)(xing)所(suo)需(xu)要的(de)(de)(de)(de)設備(bei)噸位(wei)(wei)降低(di)。熱壓(ya)三(san)(san)通(tong)(tong)對(dui)材(cai)(cai)料(liao)的(de)(de)(de)(de)適應性較寬，適用(yong)于(yu)(yu)低(di)碳鋼(gang)、合金(jin)鋼(gang)、不(bu)銹鋼(gang)的(de)(de)(de)(de)材(cai)(cai)料(liao)，特別是大(da)直(zhi)徑(jing)(jing)和管(guan)壁(bi)偏厚(hou)的(de)(de)(de)(de)三(san)(san)通(tong)(tong)，通(tong)(tong)常采用(yong)這種成(cheng)(cheng)形(xing)(xing)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(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. 對于(yu)異徑(jing)(jing)(jing)三通(tong)(tong)，首(shou)(shou)先給出(chu)最(zui)(zui)(zui)大(da)端(duan)(duan)(duan)的(de)(de)公(gong)稱(cheng)通(tong)(tong)徑(jing)(jing)(jing)，然后是(shi)與(yu)最(zui)(zui)(zui)大(da)端(duan)(duan)(duan)相對應(ying)的(de)(de)那一端(duan)(duan)(duan)的(de)(de)公(gong)稱(cheng)通(tong)(tong)徑(jing)(jing)(jing)，最(zui)(zui)(zui)后給出(chu)支管端(duan)(duan)(duan)的(de)(de)公(gong)稱(cheng)通(tong)(tong)徑(jing)(jing)(jing)；對于(yu)異徑(jing)(jing)(jing)四通(tong)(tong)，首(shou)(shou)先給出(chu)最(zui)(zui)(zui)大(da)端(duan)(duan)(duan)的(de)(de)公(gong)稱(cheng)通(tong)(tong)徑(jing)(jing)(jing)，其(qi)次是(shi)與(yu)最(zui)(zui)(zui)大(da)端(duan)(duan)(duan)相對應(ying)的(de)(de)另一端(duan)(duan)(duan)的(de)(de)公(gong)稱(cheng)通(tong)(tong)徑(jing)(jing)(jing)，第三個給出(chu)的(de)(de)是(shi)另外兩(liang)端(duan)(duan)(duan)中(zhong)較(jiao)大(da)端(duan)(duan)(duan)的(de)(de)公(gong)稱(cheng)通(tong)(tong)徑(jing)(jing)(jing)，最(zui)(zui)(zui)后給出(chu)剩余(yu)一端(duan)(duan)(duan)的(de)(de)公(gong)稱(cheng)通(tong)(tong)徑(jing)(jing)(jing)，見圖16.27。
