浙江至德鋼業有限公司為了減少不銹鋼管坯(pi)料(liao)與工模具接觸表面的溫降，有利于玻璃潤滑劑的軟化，提高潤滑效果，降低工模具表面熱沖擊引起的溫度應力，提高工模具的使用壽命，擠壓工模具使用前應進行預熱，其預熱溫度與擠壓材料和工模具的材質有關。擠壓不銹(xiu)鋼管和型材時，工模具的預熱溫度見表2-25。

 美國PMAC公(gong)司的(de)2500噸擠(ji)壓(ya)(ya)(ya)機推(tui)薦(jian)的(de)預熱(re)(re)(re)溫度(du)如下：工(gong)(gong)具鋼(gang)制作(zuo)的(de)擠(ji)壓(ya)(ya)(ya)模(mo)和(he)穿孔頭為(wei)200℃，擠(ji)壓(ya)(ya)(ya)芯棒為(wei)250~320℃，擠(ji)壓(ya)(ya)(ya)筒(tong)為(wei)260~320℃，穿孔筒(tong)為(wei)360~370℃。擠(ji)壓(ya)(ya)(ya)模(mo)、擠(ji)壓(ya)(ya)(ya)墊、芯棒等(deng)小型工(gong)(gong)模(mo)具的(de)預熱(re)(re)(re)一般采(cai)用箱式電爐(lu)。擠(ji)壓(ya)(ya)(ya)筒(tong)的(de)預熱(re)(re)(re)主要(yao)有電阻(zu)加(jia)熱(re)(re)(re)和(he)感(gan)(gan)應(ying)加(jia)熱(re)(re)(re)兩種。感(gan)(gan)應(ying)加(jia)熱(re)(re)(re)是將感(gan)(gan)應(ying)線(xian)圈放入擠(ji)壓(ya)(ya)(ya)筒(tong)內(nei)進行加(jia)熱(re)(re)(re)，加(jia)熱(re)(re)(re)時熱(re)(re)(re)流(liu)由內(nei)襯(chen)向外傳導，擠(ji)壓(ya)(ya)(ya)簡內(nei)的(de)溫度(du)分布較(jiao)電阻(zu)加(jia)熱(re)(re)(re)合理（圖2-41),因為(wei)內(nei)襯(chen)、中和(he)外套之間(jian)的(de)過盈(ying)配合應(ying)力不會降(jiang)低(di)，但感(gan)(gan)應(ying)加(jia)熱(re)(re)(re)時操作(zuo)不便，感(gan)(gan)應(ying)圈易損壞，所以(yi)目前主要(yao)還是采(cai)用電阻(zu)加(jia)熱(re)(re)(re)。

 在(zai)(zai)正(zheng)常擠(ji)(ji)(ji)(ji)壓(ya)(ya)生產(chan)不(bu)銹鋼管(guan)過(guo)(guo)(guo)(guo)程(cheng)中(zhong)，擠(ji)(ji)(ji)(ji)壓(ya)(ya)工(gong)(gong)模(mo)具(ju)連續使用(yong)(yong)時(shi)，溫(wen)度(du)將(jiang)會逐漸升(sheng)高，而(er)引起(qi)工(gong)(gong)模(mo)具(ju)材質高溫(wen)回(hui)火(huo)，降低了紅硬性，導致工(gong)(gong)模(mo)具(ju)產(chan)生變形(xing)而(er)影響擠(ji)(ji)(ji)(ji)壓(ya)(ya)過(guo)(guo)(guo)(guo)程(cheng)的順利進(jin)行(xing)。如擠(ji)(ji)(ji)(ji)壓(ya)(ya)墊的使用(yong)(yong)溫(wen)度(du)過(guo)(guo)(guo)(guo)高，因熱膨(peng)脹過(guo)(guo)(guo)(guo)大產(chan)生變形(xing)而(er)引起(qi)擠(ji)(ji)(ji)(ji)壓(ya)(ya)墊卡在(zai)(zai)擠(ji)(ji)(ji)(ji)壓(ya)(ya)筒(tong)內(nei)(nei)。為此，擠(ji)(ji)(ji)(ji)壓(ya)(ya)工(gong)(gong)模(mo)具(ju)在(zai)(zai)使用(yong)(yong)過(guo)(guo)(guo)(guo)程(cheng)中(zhong)又(you)需要進(jin)行(xing)必(bi)要的冷(leng)(leng)(leng)卻(que)(que)，使其保持在(zai)(zai)所要求的溫(wen)度(du)范圍內(nei)(nei)工(gong)(gong)作。對于(yu)外(wai)(wai)套內(nei)(nei)襯(chen)擠(ji)(ji)(ji)(ji)壓(ya)(ya)墊，擠(ji)(ji)(ji)(ji)壓(ya)(ya)模(mo)和小(xiao)直(zhi)徑(jing)的芯(xin)棒(bang)一(yi)般(ban)可(ke)(ke)以采用(yong)(yong)3~4個循(xun)(xun)環(huan)(huan)輪流使用(yong)(yong)，必(bi)要時(shi)也(ye)可(ke)(ke)以在(zai)(zai)擠(ji)(ji)(ji)(ji)壓(ya)(ya)結(jie)束后進(jin)行(xing)水(shui)(shui)冷(leng)(leng)(leng)或噴水(shui)(shui)冷(leng)(leng)(leng)卻(que)(que)。對于(yu)擠(ji)(ji)(ji)(ji)壓(ya)(ya)筒(tong)和大直(zhi)徑(jing)的芯(xin)棒(bang)等大型(xing)工(gong)(gong)模(mo)具(ju)，在(zai)(zai)使用(yong)(yong)過(guo)(guo)(guo)(guo)程(cheng)中(zhong)吸熱量大，更(geng)換(huan)又(you)不(bu)方便，故只能采用(yong)(yong)專門的冷(leng)(leng)(leng)卻(que)(que)裝置來(lai)進(jin)行(xing)冷(leng)(leng)(leng)卻(que)(que)。如擠(ji)(ji)(ji)(ji)壓(ya)(ya)筒(tong)的冷(leng)(leng)(leng)卻(que)(que)方式(shi)(shi)(shi)有內(nei)(nei)部通水(shui)(shui)冷(leng)(leng)(leng)卻(que)(que)（內(nei)(nei)冷(leng)(leng)(leng)式(shi)(shi)(shi)）和內(nei)(nei)襯(chen)噴水(shui)(shui)冷(leng)(leng)(leng)卻(que)(que)（外(wai)(wai)冷(leng)(leng)(leng)式(shi)(shi)(shi)）兩種(zhong)。內(nei)(nei)冷(leng)(leng)(leng)式(shi)(shi)(shi)（圖(tu)2-42)是(shi)在(zai)(zai)中(zhong)襯(chen)內(nei)(nei)孔(kong)表(biao)面加(jia)工(gong)(gong)有螺旋(xuan)形(xing)冷(leng)(leng)(leng)卻(que)(que)槽，當(dang)擠(ji)(ji)(ji)(ji)壓(ya)(ya)筒(tong)溫(wen)度(du)過(guo)(guo)(guo)(guo)高時(shi)，通入水(shui)(shui)溫(wen)不(bu)低于(yu)60~65℃的冷(leng)(leng)(leng)卻(que)(que)水(shui)(shui)，以防止過(guo)(guo)(guo)(guo)冷(leng)(leng)(leng)引起(qi)裂紋，設有電加(jia)熱器與水(shui)(shui)冷(leng)(leng)(leng)卻(que)(que)裝置的擠(ji)(ji)(ji)(ji)壓(ya)(ya)筒(tong)，如圖(tu)2-43所示；外(wai)(wai)冷(leng)(leng)(leng)式(shi)(shi)(shi)是(shi)當(dang)擠(ji)(ji)(ji)(ji)壓(ya)(ya)循(xun)(xun)環(huan)(huan)結(jie)束時(shi)，采用(yong)(yong)環(huan)(huan)狀噴嘴在(zai)(zai)擠(ji)(ji)(ji)(ji)壓(ya)(ya)筒(tong)一(yi)端向筒(tong)內(nei)(nei)噴入壓(ya)(ya)力水(shui)(shui)冷(leng)(leng)(leng)卻(que)(que)，這種(zhong)方法比較簡單，但內(nei)(nei)襯(chen)的材質要具(ju)有良好的耐急冷(leng)(leng)(leng)急熱性能。擠(ji)(ji)(ji)(ji)壓(ya)(ya)芯(xin)棒(bang)的冷(leng)(leng)(leng)卻(que)(que)也(ye)有內(nei)(nei)冷(leng)(leng)(leng)式(shi)(shi)(shi)和外(wai)(wai)冷(leng)(leng)(leng)式(shi)(shi)(shi)兩種(zhong)（圖(tu)2-44)。