四(si)通(tong)(tong)的(de)液(ye)壓(ya)(ya)(ya)脹形(xing)是通(tong)(tong)過(guo)金屬材料(liao)的(de)軸向補償脹出(chu)支管(guan)的(de)一種成形(xing)工藝。其過(guo)程(cheng)是采用專用液(ye)壓(ya)(ya)(ya)機，將(jiang)yu四(si)通(tong)(tong)直徑相等的(de)管(guan)坯(pi)內(nei)注入液(ye)體，通(tong)(tong)過(guo)液(ye)壓(ya)(ya)(ya)機的(de)兩(liang)個水平(ping)側缸(gang)同步對中運動擠壓(ya)(ya)(ya)管(guan)坯(pi)，管(guan)坯(pi)受擠壓(ya)(ya)(ya)后體積變(bian)小，管(guan)坯(pi)內(nei)的(de)液(ye)體隨管(guan)坯(pi)體積變(bian)小而壓(ya)(ya)(ya)力(li)升高，當達到(dao)四(si)通(tong)(tong)支管(guan)脹出(chu)所需要的(de)壓(ya)(ya)(ya)力(li)時，金屬材料(liao)在側缸(gang)和管(guan)坯(pi)內(nei)液(ye)體壓(ya)(ya)(ya)力(li)的(de)雙重作(zuo)用下(xia)沿模具(ju)內(nei)腔流動而脹出(chu)支管(guan)。