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

 美國PMAC公司的2500噸擠壓(ya)(ya)(ya)機推薦(jian)的預(yu)熱(re)(re)(re)溫度如(ru)下(xia)：工具(ju)鋼制作的擠壓(ya)(ya)(ya)模(mo)和(he)穿孔頭為(wei)(wei)200℃，擠壓(ya)(ya)(ya)芯(xin)棒為(wei)(wei)250~320℃，擠壓(ya)(ya)(ya)筒為(wei)(wei)260~320℃，穿孔筒為(wei)(wei)360~370℃。擠壓(ya)(ya)(ya)模(mo)、擠壓(ya)(ya)(ya)墊、芯(xin)棒等(deng)小型(xing)工模(mo)具(ju)的預(yu)熱(re)(re)(re)一般采用箱(xiang)式電(dian)爐(lu)。擠壓(ya)(ya)(ya)筒的預(yu)熱(re)(re)(re)主(zhu)要(yao)(yao)有電(dian)阻加(jia)(jia)(jia)熱(re)(re)(re)和(he)感(gan)應(ying)(ying)加(jia)(jia)(jia)熱(re)(re)(re)兩種。感(gan)應(ying)(ying)加(jia)(jia)(jia)熱(re)(re)(re)是(shi)將感(gan)應(ying)(ying)線(xian)圈放入擠壓(ya)(ya)(ya)筒內進行加(jia)(jia)(jia)熱(re)(re)(re)，加(jia)(jia)(jia)熱(re)(re)(re)時(shi)熱(re)(re)(re)流由內襯向外(wai)傳導，擠壓(ya)(ya)(ya)簡內的溫度分布較(jiao)電(dian)阻加(jia)(jia)(jia)熱(re)(re)(re)合(he)(he)理（圖2-41),因為(wei)(wei)內襯、中和(he)外(wai)套(tao)之間(jian)的過(guo)盈配合(he)(he)應(ying)(ying)力(li)不會降(jiang)低，但感(gan)應(ying)(ying)加(jia)(jia)(jia)熱(re)(re)(re)時(shi)操(cao)作不便，感(gan)應(ying)(ying)圈易(yi)損壞，所以目前(qian)主(zhu)要(yao)(yao)還是(shi)采用電(dian)阻加(jia)(jia)(jia)熱(re)(re)(re)。

 在正常擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)生產不(bu)銹鋼管過(guo)程中，擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)工(gong)(gong)模(mo)(mo)具連(lian)續(xu)使(shi)用(yong)(yong)(yong)(yong)時(shi)(shi)，溫(wen)(wen)度(du)(du)將會逐漸升(sheng)高(gao)(gao)(gao)(gao)，而引起(qi)工(gong)(gong)模(mo)(mo)具材(cai)質高(gao)(gao)(gao)(gao)溫(wen)(wen)回火，降低了(le)紅(hong)硬性(xing)(xing)，導致(zhi)工(gong)(gong)模(mo)(mo)具產生變形而影響擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)過(guo)程的(de)(de)(de)順利進(jin)行。如(ru)(ru)擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)墊(dian)的(de)(de)(de)使(shi)用(yong)(yong)(yong)(yong)溫(wen)(wen)度(du)(du)過(guo)高(gao)(gao)(gao)(gao)，因(yin)熱(re)膨脹過(guo)大產生變形而引起(qi)擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)墊(dian)卡在擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)筒內(nei)(nei)(nei)(nei)(nei)。為此，擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)工(gong)(gong)模(mo)(mo)具在使(shi)用(yong)(yong)(yong)(yong)過(guo)程中又(you)需要進(jin)行必要的(de)(de)(de)冷(leng)(leng)卻(que)(que)(que)，使(shi)其保持(chi)在所(suo)要求的(de)(de)(de)溫(wen)(wen)度(du)(du)范圍內(nei)(nei)(nei)(nei)(nei)工(gong)(gong)作。對于(yu)(yu)外(wai)(wai)套內(nei)(nei)(nei)(nei)(nei)襯擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)墊(dian)，擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)模(mo)(mo)和小直徑的(de)(de)(de)芯棒(bang)一般(ban)可(ke)以采用(yong)(yong)(yong)(yong)3~4個循(xun)環輪流使(shi)用(yong)(yong)(yong)(yong)，必要時(shi)(shi)也可(ke)以在擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)結束(shu)后進(jin)行水(shui)冷(leng)(leng)或噴(pen)水(shui)冷(leng)(leng)卻(que)(que)(que)。對于(yu)(yu)擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)筒和大直徑的(de)(de)(de)芯棒(bang)等(deng)大型(xing)工(gong)(gong)模(mo)(mo)具，在使(shi)用(yong)(yong)(yong)(yong)過(guo)程中吸(xi)熱(re)量大，更換又(you)不(bu)方便(bian)，故只能(neng)采用(yong)(yong)(yong)(yong)專門的(de)(de)(de)冷(leng)(leng)卻(que)(que)(que)裝置來進(jin)行冷(leng)(leng)卻(que)(que)(que)。如(ru)(ru)擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)筒的(de)(de)(de)冷(leng)(leng)卻(que)(que)(que)方式(shi)有內(nei)(nei)(nei)(nei)(nei)部通水(shui)冷(leng)(leng)卻(que)(que)(que)（內(nei)(nei)(nei)(nei)(nei)冷(leng)(leng)式(shi)）和內(nei)(nei)(nei)(nei)(nei)襯噴(pen)水(shui)冷(leng)(leng)卻(que)(que)(que)（外(wai)(wai)冷(leng)(leng)式(shi)）兩種。內(nei)(nei)(nei)(nei)(nei)冷(leng)(leng)式(shi)（圖(tu)2-42)是(shi)在中襯內(nei)(nei)(nei)(nei)(nei)孔(kong)表面加工(gong)(gong)有螺(luo)旋形冷(leng)(leng)卻(que)(que)(que)槽，當擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)筒溫(wen)(wen)度(du)(du)過(guo)高(gao)(gao)(gao)(gao)時(shi)(shi)，通入(ru)(ru)水(shui)溫(wen)(wen)不(bu)低于(yu)(yu)60~65℃的(de)(de)(de)冷(leng)(leng)卻(que)(que)(que)水(shui)，以防止過(guo)冷(leng)(leng)引起(qi)裂(lie)紋，設有電加熱(re)器與水(shui)冷(leng)(leng)卻(que)(que)(que)裝置的(de)(de)(de)擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)筒，如(ru)(ru)圖(tu)2-43所(suo)示；外(wai)(wai)冷(leng)(leng)式(shi)是(shi)當擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)循(xun)環結束(shu)時(shi)(shi)，采用(yong)(yong)(yong)(yong)環狀噴(pen)嘴在擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)筒一端向筒內(nei)(nei)(nei)(nei)(nei)噴(pen)入(ru)(ru)壓(ya)(ya)(ya)(ya)力(li)水(shui)冷(leng)(leng)卻(que)(que)(que)，這種方法比較簡單，但(dan)內(nei)(nei)(nei)(nei)(nei)襯的(de)(de)(de)材(cai)質要具有良好(hao)的(de)(de)(de)耐急冷(leng)(leng)急熱(re)性(xing)(xing)能(neng)。擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)芯棒(bang)的(de)(de)(de)冷(leng)(leng)卻(que)(que)(que)也有內(nei)(nei)(nei)(nei)(nei)冷(leng)(leng)式(shi)和外(wai)(wai)冷(leng)(leng)式(shi)兩種（圖(tu)2-44)。