浙江至德鋼業有限公司技術人員用壓力將經過加熱的不銹鋼彎頭推向一個后端加以固定的頂桿，該頂桿的頂頭位于由一對軋輥組成的圓孔型的中心，因此軸向的推力和徑向的軋制力同時作用在方坯上，使彎頭經過頂頭和圓孔型穿孔成為空心坯。在變形過程中只出現壓應力、基本上消除了拉伸應力、剪切應力和連續滑動現象，故穿孔后的不銹鋼彎頭的金屬組織大大改善。

  如圖(tu)17-1所示(shi)，經過加熱(re)(re)的(de)(de)不(bu)銹(xiu)(xiu)鋼彎頭BL經消除氧(yang)化鐵皮和定(ding)型后，被送至(zhi)壓(ya)(ya)力(li)穿(chuan)(chuan)(chuan)(chuan)孔(kong)(kong)(kong)機(ji)(ji)的(de)(de)受料槽內(nei)，并(bing)處于液(ye)(ye)壓(ya)(ya)推(tui)鋼機(ji)(ji)AP和軋(ya)(ya)機(ji)(ji)機(ji)(ji)架間。液(ye)(ye)力(li)推(tui)鋼機(ji)(ji)AP將經過熱(re)(re)定(ding)心(xin)的(de)(de)方(fang)坯(pi)(pi)(pi)(pi)推(tui)入一個(ge)堅(jian)固的(de)(de)、公差很小的(de)(de)方(fang)形入口(kou)(kou)導(dao)套(tao)IG,使(shi)方(fang)坯(pi)(pi)(pi)(pi)同時(shi)(shi)和穿(chuan)(chuan)(chuan)(chuan)孔(kong)(kong)(kong)機(ji)(ji)頭PP和軋(ya)(ya)輥RG相(xiang)遇(yu)(yu)，并(bing)在整(zheng)個(ge)穿(chuan)(chuan)(chuan)(chuan)孔(kong)(kong)(kong)過程維持(chi)恒定(ding)的(de)(de)推(tui)力(li)，然后即(ji)作(zuo)用在它(ta)圓(yuan)形的(de)(de)外表(biao)面上，當(dang)空(kong)(kong)心(xin)坯(pi)(pi)(pi)(pi)HB由軋(ya)(ya)輥孔(kong)(kong)(kong)型中(zhong)(zhong)軋(ya)(ya)出時(shi)(shi)，立即(ji)進(jin)入堅(jian)固的(de)(de)配合得(de)很緊密的(de)(de)出口(kou)(kou)中(zhong)(zhong)導(dao)套(tao)OG.導(dao)環CG,在穿(chuan)(chuan)(chuan)(chuan)孔(kong)(kong)(kong)開始時(shi)(shi)位于頂(ding)(ding)桿(gan)PB的(de)(de)前(qian)(qian)端，而當(dang)空(kong)(kong)心(xin)坯(pi)(pi)(pi)(pi)進(jin)入出口(kou)(kou)導(dao)套(tao)0G時(shi)(shi)，它(ta)與導(dao)環CG相(xiang)遇(yu)(yu)，并(bing)推(tui)動導(dao)環CG前(qian)(qian)進(jin)而空(kong)(kong)心(xin)坯(pi)(pi)(pi)(pi)本(ben)身逐漸起(qi)到定(ding)心(xin)的(de)(de)作(zuo)用。因此只(zhi)要(yao)正確地調整(zheng)入口(kou)(kou)導(dao)套(tao)IG,軋(ya)(ya)輥RG和出口(kou)(kou)導(dao)套(tao)OG即(ji)可保證不(bu)銹(xiu)(xiu)鋼彎頭、頂(ding)(ding)頭與頂(ding)(ding)桿(gan)三者的(de)(de)中(zhong)(zhong)心(xin)線(xian)在同一直(zhi)(zhi)線(xian)上，故壓(ya)(ya)力(li)穿(chuan)(chuan)(chuan)(chuan)孔(kong)(kong)(kong)后，空(kong)(kong)心(xin)坯(pi)(pi)(pi)(pi)壁厚比較均勻。當(dang)穿(chuan)(chuan)(chuan)(chuan)孔(kong)(kong)(kong)操作(zuo)將要(yao)結束時(shi)(shi)，液(ye)(ye)力(li)推(tui)鋼機(ji)(ji)的(de)(de)柱塞桿(gan)IP自動停止(zhi)前(qian)(qian)進(jin)，而推(tui)鋼機(ji)(ji)外環繼續(xu)前(qian)(qian)進(jin)，直(zhi)(zhi)至(zhi)與頂(ding)(ding)頭相(xiang)遇(yu)(yu)為止(zhi)，此時(shi)(shi)不(bu)銹(xiu)(xiu)鋼彎頭后部的(de)(de)穿(chuan)(chuan)(chuan)(chuan)孔(kong)(kong)(kong)全靠徑向(xiang)軋(ya)(ya)制力(li)來完成。方(fang)坯(pi)(pi)(pi)(pi)穿(chuan)(chuan)(chuan)(chuan)孔(kong)(kong)(kong)后，打開鎖門，水冷頂(ding)(ding)桿(gan)由空(kong)(kong)心(xin)坯(pi)(pi)(pi)(pi)內(nei)抽出，其動作(zuo)和斜軋(ya)(ya)穿(chuan)(chuan)(chuan)(chuan)孔(kong)(kong)(kong)機(ji)(ji)是相(xiang)同的(de)(de)。