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(mei)國PMAC公司的(de)(de)2500噸(dun)擠(ji)(ji)(ji)壓(ya)機推薦的(de)(de)預(yu)熱(re)溫度如(ru)下：工(gong)具(ju)(ju)鋼制作的(de)(de)擠(ji)(ji)(ji)壓(ya)模和(he)穿孔(kong)頭為(wei)(wei)200℃，擠(ji)(ji)(ji)壓(ya)芯棒(bang)為(wei)(wei)250~320℃，擠(ji)(ji)(ji)壓(ya)筒(tong)(tong)為(wei)(wei)260~320℃，穿孔(kong)筒(tong)(tong)為(wei)(wei)360~370℃。擠(ji)(ji)(ji)壓(ya)模、擠(ji)(ji)(ji)壓(ya)墊(dian)、芯棒(bang)等(deng)小型工(gong)模具(ju)(ju)的(de)(de)預(yu)熱(re)一(yi)般采(cai)用箱式電(dian)爐。擠(ji)(ji)(ji)壓(ya)筒(tong)(tong)的(de)(de)預(yu)熱(re)主要有電(dian)阻加(jia)(jia)熱(re)和(he)感應(ying)加(jia)(jia)熱(re)兩種。感應(ying)加(jia)(jia)熱(re)是將感應(ying)線(xian)圈放入(ru)擠(ji)(ji)(ji)壓(ya)筒(tong)(tong)內(nei)(nei)進行加(jia)(jia)熱(re)，加(jia)(jia)熱(re)時熱(re)流由(you)內(nei)(nei)襯(chen)(chen)向外(wai)傳導(dao)，擠(ji)(ji)(ji)壓(ya)簡內(nei)(nei)的(de)(de)溫度分布(bu)較(jiao)電(dian)阻加(jia)(jia)熱(re)合理(li)（圖2-41),因(yin)為(wei)(wei)內(nei)(nei)襯(chen)(chen)、中(zhong)和(he)外(wai)套之間的(de)(de)過盈配合應(ying)力(li)不會降低，但感應(ying)加(jia)(jia)熱(re)時操作不便，感應(ying)圈易損壞，所以目(mu)前主要還是采(cai)用電(dian)阻加(jia)(jia)熱(re)。

 在(zai)(zai)正(zheng)常擠(ji)壓(ya)(ya)(ya)(ya)生產不(bu)銹鋼管(guan)過(guo)(guo)(guo)(guo)(guo)程(cheng)(cheng)中，擠(ji)壓(ya)(ya)(ya)(ya)工(gong)(gong)模(mo)具(ju)(ju)連(lian)續使(shi)(shi)用(yong)時，溫(wen)(wen)度(du)將會逐(zhu)漸升高，而引起(qi)工(gong)(gong)模(mo)具(ju)(ju)材(cai)質高溫(wen)(wen)回(hui)火，降(jiang)低(di)了紅硬性(xing)(xing)，導致工(gong)(gong)模(mo)具(ju)(ju)產生變形(xing)(xing)而影(ying)響擠(ji)壓(ya)(ya)(ya)(ya)過(guo)(guo)(guo)(guo)(guo)程(cheng)(cheng)的(de)(de)(de)(de)順(shun)利(li)進(jin)(jin)行。如(ru)擠(ji)壓(ya)(ya)(ya)(ya)墊(dian)的(de)(de)(de)(de)使(shi)(shi)用(yong)溫(wen)(wen)度(du)過(guo)(guo)(guo)(guo)(guo)高，因熱(re)(re)膨脹(zhang)過(guo)(guo)(guo)(guo)(guo)大產生變形(xing)(xing)而引起(qi)擠(ji)壓(ya)(ya)(ya)(ya)墊(dian)卡在(zai)(zai)擠(ji)壓(ya)(ya)(ya)(ya)筒(tong)(tong)內。為(wei)此，擠(ji)壓(ya)(ya)(ya)(ya)工(gong)(gong)模(mo)具(ju)(ju)在(zai)(zai)使(shi)(shi)用(yong)過(guo)(guo)(guo)(guo)(guo)程(cheng)(cheng)中又需要進(jin)(jin)行必要的(de)(de)(de)(de)冷(leng)(leng)(leng)(leng)(leng)卻(que)(que)(que)，使(shi)(shi)其保持在(zai)(zai)所要求的(de)(de)(de)(de)溫(wen)(wen)度(du)范(fan)圍內工(gong)(gong)作(zuo)。對于(yu)(yu)外(wai)(wai)套內襯(chen)擠(ji)壓(ya)(ya)(ya)(ya)墊(dian)，擠(ji)壓(ya)(ya)(ya)(ya)模(mo)和(he)(he)小直(zhi)(zhi)徑的(de)(de)(de)(de)芯(xin)棒(bang)一般可以(yi)采(cai)(cai)用(yong)3~4個循(xun)環輪流(liu)使(shi)(shi)用(yong)，必要時也(ye)可以(yi)在(zai)(zai)擠(ji)壓(ya)(ya)(ya)(ya)結束(shu)(shu)后進(jin)(jin)行水(shui)(shui)(shui)冷(leng)(leng)(leng)(leng)(leng)或噴(pen)水(shui)(shui)(shui)冷(leng)(leng)(leng)(leng)(leng)卻(que)(que)(que)。對于(yu)(yu)擠(ji)壓(ya)(ya)(ya)(ya)筒(tong)(tong)和(he)(he)大直(zhi)(zhi)徑的(de)(de)(de)(de)芯(xin)棒(bang)等(deng)大型(xing)工(gong)(gong)模(mo)具(ju)(ju)，在(zai)(zai)使(shi)(shi)用(yong)過(guo)(guo)(guo)(guo)(guo)程(cheng)(cheng)中吸熱(re)(re)量(liang)大，更(geng)換又不(bu)方便，故(gu)只能(neng)采(cai)(cai)用(yong)專(zhuan)門的(de)(de)(de)(de)冷(leng)(leng)(leng)(leng)(leng)卻(que)(que)(que)裝置(zhi)來進(jin)(jin)行冷(leng)(leng)(leng)(leng)(leng)卻(que)(que)(que)。如(ru)擠(ji)壓(ya)(ya)(ya)(ya)筒(tong)(tong)的(de)(de)(de)(de)冷(leng)(leng)(leng)(leng)(leng)卻(que)(que)(que)方式(shi)有(you)內部(bu)通水(shui)(shui)(shui)冷(leng)(leng)(leng)(leng)(leng)卻(que)(que)(que)（內冷(leng)(leng)(leng)(leng)(leng)式(shi)）和(he)(he)內襯(chen)噴(pen)水(shui)(shui)(shui)冷(leng)(leng)(leng)(leng)(leng)卻(que)(que)(que)（外(wai)(wai)冷(leng)(leng)(leng)(leng)(leng)式(shi)）兩種(zhong)(zhong)。內冷(leng)(leng)(leng)(leng)(leng)式(shi)（圖2-42)是在(zai)(zai)中襯(chen)內孔(kong)表面(mian)加(jia)工(gong)(gong)有(you)螺旋形(xing)(xing)冷(leng)(leng)(leng)(leng)(leng)卻(que)(que)(que)槽，當(dang)擠(ji)壓(ya)(ya)(ya)(ya)筒(tong)(tong)溫(wen)(wen)度(du)過(guo)(guo)(guo)(guo)(guo)高時，通入(ru)水(shui)(shui)(shui)溫(wen)(wen)不(bu)低(di)于(yu)(yu)60~65℃的(de)(de)(de)(de)冷(leng)(leng)(leng)(leng)(leng)卻(que)(que)(que)水(shui)(shui)(shui)，以(yi)防止過(guo)(guo)(guo)(guo)(guo)冷(leng)(leng)(leng)(leng)(leng)引起(qi)裂(lie)紋(wen)，設有(you)電加(jia)熱(re)(re)器與(yu)水(shui)(shui)(shui)冷(leng)(leng)(leng)(leng)(leng)卻(que)(que)(que)裝置(zhi)的(de)(de)(de)(de)擠(ji)壓(ya)(ya)(ya)(ya)筒(tong)(tong)，如(ru)圖2-43所示；外(wai)(wai)冷(leng)(leng)(leng)(leng)(leng)式(shi)是當(dang)擠(ji)壓(ya)(ya)(ya)(ya)循(xun)環結束(shu)(shu)時，采(cai)(cai)用(yong)環狀噴(pen)嘴在(zai)(zai)擠(ji)壓(ya)(ya)(ya)(ya)筒(tong)(tong)一端(duan)向筒(tong)(tong)內噴(pen)入(ru)壓(ya)(ya)(ya)(ya)力(li)水(shui)(shui)(shui)冷(leng)(leng)(leng)(leng)(leng)卻(que)(que)(que)，這種(zhong)(zhong)方法(fa)比較(jiao)簡單，但內襯(chen)的(de)(de)(de)(de)材(cai)質要具(ju)(ju)有(you)良好(hao)的(de)(de)(de)(de)耐急(ji)冷(leng)(leng)(leng)(leng)(leng)急(ji)熱(re)(re)性(xing)(xing)能(neng)。擠(ji)壓(ya)(ya)(ya)(ya)芯(xin)棒(bang)的(de)(de)(de)(de)冷(leng)(leng)(leng)(leng)(leng)卻(que)(que)(que)也(ye)有(you)內冷(leng)(leng)(leng)(leng)(leng)式(shi)和(he)(he)外(wai)(wai)冷(leng)(leng)(leng)(leng)(leng)式(shi)兩種(zhong)(zhong)（圖2-44)。