浙江至德鋼業有限公司為了減少不(bu)銹鋼管坯料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。擠壓不銹鋼管和型材時，工模具的預熱溫度見表2-25。

 美國PMAC公司(si)的2500噸擠(ji)壓(ya)(ya)機推薦的預(yu)(yu)熱(re)(re)溫度如下：工具鋼制(zhi)作的擠(ji)壓(ya)(ya)模(mo)(mo)和(he)(he)穿孔(kong)頭為(wei)200℃，擠(ji)壓(ya)(ya)芯棒(bang)為(wei)250~320℃，擠(ji)壓(ya)(ya)筒為(wei)260~320℃，穿孔(kong)筒為(wei)360~370℃。擠(ji)壓(ya)(ya)模(mo)(mo)、擠(ji)壓(ya)(ya)墊、芯棒(bang)等小(xiao)型工模(mo)(mo)具的預(yu)(yu)熱(re)(re)一(yi)般采用(yong)箱式電(dian)爐。擠(ji)壓(ya)(ya)筒的預(yu)(yu)熱(re)(re)主要(yao)有電(dian)阻(zu)加熱(re)(re)和(he)(he)感應(ying)加熱(re)(re)兩種。感應(ying)加熱(re)(re)是將感應(ying)線(xian)圈放入擠(ji)壓(ya)(ya)筒內(nei)進行加熱(re)(re)，加熱(re)(re)時熱(re)(re)流由內(nei)襯向外傳導，擠(ji)壓(ya)(ya)簡內(nei)的溫度分布較電(dian)阻(zu)加熱(re)(re)合理（圖2-41),因為(wei)內(nei)襯、中和(he)(he)外套之間(jian)的過盈配合應(ying)力(li)不會降低，但(dan)感應(ying)加熱(re)(re)時操作不便，感應(ying)圈易損壞，所(suo)以目前(qian)主要(yao)還是采用(yong)電(dian)阻(zu)加熱(re)(re)。

 在正常(chang)擠(ji)(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)生產不(bu)銹(xiu)鋼(gang)管過(guo)(guo)(guo)程(cheng)(cheng)中(zhong)(zhong)，擠(ji)(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)工(gong)(gong)(gong)模(mo)(mo)具(ju)連續使(shi)用(yong)(yong)時，溫度(du)將會逐漸升(sheng)高(gao)，而(er)引起工(gong)(gong)(gong)模(mo)(mo)具(ju)材(cai)質(zhi)高(gao)溫回火，降低了紅硬(ying)性，導致工(gong)(gong)(gong)模(mo)(mo)具(ju)產生變形而(er)影響擠(ji)(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)過(guo)(guo)(guo)程(cheng)(cheng)的順利進行。如擠(ji)(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)墊的使(shi)用(yong)(yong)溫度(du)過(guo)(guo)(guo)高(gao)，因(yin)熱(re)(re)膨脹過(guo)(guo)(guo)大(da)產生變形而(er)引起擠(ji)(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)墊卡在擠(ji)(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)筒(tong)(tong)(tong)(tong)內(nei)(nei)(nei)。為(wei)此(ci)，擠(ji)(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)工(gong)(gong)(gong)模(mo)(mo)具(ju)在使(shi)用(yong)(yong)過(guo)(guo)(guo)程(cheng)(cheng)中(zhong)(zhong)又需要(yao)進行必(bi)要(yao)的冷(leng)(leng)(leng)卻(que)(que)(que)(que)，使(shi)其保持在所要(yao)求的溫度(du)范(fan)圍內(nei)(nei)(nei)工(gong)(gong)(gong)作。對于外(wai)套內(nei)(nei)(nei)襯(chen)(chen)擠(ji)(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)墊，擠(ji)(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)模(mo)(mo)和小(xiao)直徑的芯棒一(yi)般可以(yi)采(cai)用(yong)(yong)3~4個循環輪(lun)流使(shi)用(yong)(yong)，必(bi)要(yao)時也可以(yi)在擠(ji)(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)結束后(hou)進行水(shui)(shui)冷(leng)(leng)(leng)或噴(pen)水(shui)(shui)冷(leng)(leng)(leng)卻(que)(que)(que)(que)。對于擠(ji)(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)筒(tong)(tong)(tong)(tong)和大(da)直徑的芯棒等大(da)型工(gong)(gong)(gong)模(mo)(mo)具(ju)，在使(shi)用(yong)(yong)過(guo)(guo)(guo)程(cheng)(cheng)中(zhong)(zhong)吸熱(re)(re)量大(da)，更換(huan)又不(bu)方便，故只(zhi)能采(cai)用(yong)(yong)專門的冷(leng)(leng)(leng)卻(que)(que)(que)(que)裝置來進行冷(leng)(leng)(leng)卻(que)(que)(que)(que)。如擠(ji)(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)筒(tong)(tong)(tong)(tong)的冷(leng)(leng)(leng)卻(que)(que)(que)(que)方式有(you)(you)(you)內(nei)(nei)(nei)部通水(shui)(shui)冷(leng)(leng)(leng)卻(que)(que)(que)(que)（內(nei)(nei)(nei)冷(leng)(leng)(leng)式）和內(nei)(nei)(nei)襯(chen)(chen)噴(pen)水(shui)(shui)冷(leng)(leng)(leng)卻(que)(que)(que)(que)（外(wai)冷(leng)(leng)(leng)式）兩種(zhong)(zhong)。內(nei)(nei)(nei)冷(leng)(leng)(leng)式（圖(tu)2-42)是(shi)在中(zhong)(zhong)襯(chen)(chen)內(nei)(nei)(nei)孔表(biao)面加(jia)工(gong)(gong)(gong)有(you)(you)(you)螺旋形冷(leng)(leng)(leng)卻(que)(que)(que)(que)槽(cao)，當擠(ji)(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)筒(tong)(tong)(tong)(tong)溫度(du)過(guo)(guo)(guo)高(gao)時，通入水(shui)(shui)溫不(bu)低于60~65℃的冷(leng)(leng)(leng)卻(que)(que)(que)(que)水(shui)(shui)，以(yi)防止過(guo)(guo)(guo)冷(leng)(leng)(leng)引起裂紋，設有(you)(you)(you)電加(jia)熱(re)(re)器與水(shui)(shui)冷(leng)(leng)(leng)卻(que)(que)(que)(que)裝置的擠(ji)(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)筒(tong)(tong)(tong)(tong)，如圖(tu)2-43所示；外(wai)冷(leng)(leng)(leng)式是(shi)當擠(ji)(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)循環結束時，采(cai)用(yong)(yong)環狀噴(pen)嘴在擠(ji)(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)筒(tong)(tong)(tong)(tong)一(yi)端向(xiang)筒(tong)(tong)(tong)(tong)內(nei)(nei)(nei)噴(pen)入壓(ya)(ya)(ya)(ya)(ya)力水(shui)(shui)冷(leng)(leng)(leng)卻(que)(que)(que)(que)，這種(zhong)(zhong)方法比較簡單，但內(nei)(nei)(nei)襯(chen)(chen)的材(cai)質(zhi)要(yao)具(ju)有(you)(you)(you)良好的耐急冷(leng)(leng)(leng)急熱(re)(re)性能。擠(ji)(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)芯棒的冷(leng)(leng)(leng)卻(que)(que)(que)(que)也有(you)(you)(you)內(nei)(nei)(nei)冷(leng)(leng)(leng)式和外(wai)冷(leng)(leng)(leng)式兩種(zhong)(zhong)（圖(tu)2-44)。