冷(leng)(leng)拔(ba)三(san)(san)通(tong)(tong)成形(xing)(xing)是將大(da)于(yu)三(san)(san)通(tong)(tong)直(zhi)(zhi)徑(jing)(jing)的管(guan)(guan)坯,壓(ya)(ya)扁約(yue)至冷(leng)(leng)拔(ba)三(san)(san)通(tong)(tong)直(zhi)(zhi)徑(jing)(jing)的尺(chi)寸,在(zai)拉(la)伸支管(guan)(guan)的部位開一個(ge)孔;管(guan)(guan)坯經加熱,放入成形(xing)(xing)模(mo)中,并在(zai)管(guan)(guan)坯內裝入拉(la)伸支管(guan)(guan)的沖模(mo);在(zai)壓(ya)(ya)力的作(zuo)用下(xia)(xia)管(guan)(guan)坯被徑(jing)(jing)向(xiang)(xiang)壓(ya)(ya)縮(suo),在(zai)徑(jing)(jing)向(xiang)(xiang)壓(ya)(ya)縮(suo)的過(guo)程中金屬(shu)向(xiang)(xiang)支管(guan)(guan)方(fang)向(xiang)(xiang)流(liu)動(dong)并在(zai)沖模(mo)的拉(la)伸下(xia)(xia)形(xing)(xing)成支管(guan)(guan)。整(zheng)個(ge)過(guo)程是通(tong)(tong)過(guo)管(guan)(guan)坯的徑(jing)(jing)向(xiang)(xiang)壓(ya)(ya)縮(suo)和支管(guan)(guan)部位的拉(la)伸過(guo)程而(er)成形(xing)(xing)。與(yu)液(ye)壓(ya)(ya)脹形(xing)(xing)冷(leng)(leng)拔(ba)三(san)(san)通(tong)(tong)不(bu)同的是,冷(leng)(leng)拔(ba)三(san)(san)通(tong)(tong)支管(guan)(guan)的金屬(shu)是由(you)管(guan)(guan)坯的徑(jing)(jing)向(xiang)(xiang)運動(dong)進行補(bu)償(chang)的,所以也稱為徑(jing)(jing)向(xiang)(xiang)補(bu)償(chang)工(gong)藝。
由(you)于采(cai)(cai)用加熱后壓制冷(leng)(leng)拔(ba)三(san)通(tong),材(cai)料成形(xing)所需要的(de)(de)(de)設備噸位降低。熱壓冷(leng)(leng)拔(ba)三(san)通(tong)對材(cai)料的(de)(de)(de)適應性較寬,適用于低碳鋼、合金鋼、不銹鋼的(de)(de)(de)材(cai)料;特別是大直徑(jing)和管壁偏厚的(de)(de)(de)冷(leng)(leng)拔(ba)三(san)通(tong),通(tong)常采(cai)(cai)用這種(zhong)成形(xing)工藝。
冷拔三通(tong)對接形式分類(lei):
1、對(dui)(dui)焊(han)式(shi)冷(leng)拔三通:就(jiu)是和連接管件對(dui)(dui)接后焊(han)接的冷(leng)拔三通。
2、承插式冷拔三(san)通(tong):就(jiu)是把連接管件(jian)插入三(san)通(tong)各端(duan)部后(hou)焊接或熔接的冷拔三(san)通(tong)。
3、卡套式冷(leng)拔三通(tong):就是各端部是卡套接頭,把管件插入后再(zai)緊固的冷(leng)拔三通(tong)。
4、螺紋式(shi)冷(leng)拔三(san)通:以螺紋方式(shi)連接(jie)管件的冷(leng)拔三(san)通。