1. 桶形輥穿孔機
桶(tong)形二輥穿(chuan)孔機是根據孔腔形成(cheng)原理(li),利用旋轉(zhuan)橫鍛效應穿(chuan)孔。正(zheng)是這種孔腔現象造成(cheng)了鋼(gang)管內表面的缺(que)陷,旋轉(zhuan)橫鍛效應又(you)使毛(mao)管有較大的周(zhou)向切應力和(he)表面扭轉(zhuan)變(bian)形,因此,桶(tong)式穿(chuan)孔機很難滿足穿(chuan)軋高合金(jin)鋼(gang)的要(yao)求。
2. 錐(zhui)形輥穿(chuan)孔(kong)機
錐(zhui)形(xing)(xing)(xing)輥(gun)穿(chuan)(chuan)孔機(ji)采用(yong)較大(da)的(de)(de)輾軋(ya)(ya)(ya)(ya)角(jiao)和(he)送(song)進(jin)(jin)角(jiao)進(jin)(jin)行(xing)斜軋(ya)(ya)(ya)(ya)穿(chuan)(chuan)孔,同時(shi)又極力控制旋(xuan)轉橫鍛(duan)效應(ying)的(de)(de)產生及控制毛管的(de)(de)周向切應(ying)力與表(biao)面扭轉變(bian)形(xing)(xing)(xing)。因此(ci),錐(zhui)形(xing)(xing)(xing)輥(gun)穿(chuan)(chuan)孔機(ji)可(ke)以實現與擠(ji)壓機(ji)相(xiang)近的(de)(de)金屬流動。從(cong)(cong)工藝參數(shu)方面講(jiang),錐(zhui)形(xing)(xing)(xing)輥(gun)穿(chuan)(chuan)孔機(ji)基本要(yao)點(dian)是兩個(ge)角(jiao)度(du)值的(de)(de)問(wen)題即輾軋(ya)(ya)(ya)(ya)角(jiao)和(he)送(song)進(jin)(jin)角(jiao)。前者(zhe)對一(yi)(yi)個(ge)機(ji)組來(lai)講(jiang)是定值,后(hou)者(zhe)根據設計(ji)可(ke)調整,若錐(zhui)形(xing)(xing)(xing)輥(gun)穿(chuan)(chuan)孔機(ji)采取軋(ya)(ya)(ya)(ya)輥(gun)水平(ping)布置方式,故可(ke)采用(yong)更大(da)的(de)(de)輾軋(ya)(ya)(ya)(ya)角(jiao)β(27.6°)和(he)相(xiang)對較小的(de)(de)送(song)進(jin)(jin)角(jiao)α(6°~12°),若這種軋(ya)(ya)(ya)(ya)機(ji)發(fa)展為軋(ya)(ya)(ya)(ya)輥(gun)上下布置時(shi),這樣大(da)的(de)(de)輾軋(ya)(ya)(ya)(ya)角(jiao)顯然不行(xing),而且(qie)從(cong)(cong)工藝上講(jiang),一(yi)(yi)般以β+α=25°~30°作為一(yi)(yi)判(pan)定值,故曼內(nei)斯曼鋼管公司在后(hou)來(lai)的(de)(de)設計(ji)中,隨著軋(ya)(ya)(ya)(ya)輥(gun)上下布置形(xing)(xing)(xing)式的(de)(de)進(jin)(jin)一(yi)(yi)步發(fa)展,將β角(jiao)降(jiang)為10°~15°。輾軋(ya)(ya)(ya)(ya)角(jiao)和(he)可(ke)調的(de)(de)送(song)進(jin)(jin)角(jiao)的(de)(de)各種配合,對穿(chuan)(chuan)孔過程中所發(fa)生的(de)(de)切向變(bian)形(xing)(xing)(xing)確實產生相(xiang)當大(da)的(de)(de)影(ying)響。

