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(de)2500噸擠(ji)壓機推薦的(de)預熱溫度(du)如下：工具鋼制作(zuo)的(de)擠(ji)壓模和穿孔頭為(wei)200℃，擠(ji)壓芯(xin)棒為(wei)250~320℃，擠(ji)壓筒為(wei)260~320℃，穿孔筒為(wei)360~370℃。擠(ji)壓模、擠(ji)壓墊、芯(xin)棒等小型工模具的(de)預熱一(yi)般(ban)采用(yong)箱式電爐。擠(ji)壓筒的(de)預熱主(zhu)要(yao)(yao)有電阻加(jia)(jia)熱和感(gan)應(ying)加(jia)(jia)熱兩(liang)種。感(gan)應(ying)加(jia)(jia)熱是將感(gan)應(ying)線圈(quan)放(fang)入擠(ji)壓筒內進行加(jia)(jia)熱，加(jia)(jia)熱時熱流由內襯(chen)向外傳導(dao)，擠(ji)壓簡(jian)內的(de)溫度(du)分布較電阻加(jia)(jia)熱合理(li)（圖2-41),因為(wei)內襯(chen)、中和外套之間的(de)過(guo)盈(ying)配合應(ying)力(li)不會降低，但感(gan)應(ying)加(jia)(jia)熱時操(cao)作(zuo)不便(bian)，感(gan)應(ying)圈(quan)易(yi)損(sun)壞，所以目(mu)前(qian)主(zhu)要(yao)(yao)還是采用(yong)電阻加(jia)(jia)熱。

 在正常擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)(ya)生(sheng)產(chan)不銹鋼管過(guo)(guo)程(cheng)中(zhong)，擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)(ya)工模(mo)具(ju)連續使(shi)用(yong)(yong)(yong)時(shi)，溫(wen)度(du)將(jiang)會逐漸升高，而引起工模(mo)具(ju)材(cai)質高溫(wen)回(hui)火，降低(di)了紅硬性(xing)(xing)，導致(zhi)工模(mo)具(ju)產(chan)生(sheng)變(bian)形而影響擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)(ya)過(guo)(guo)程(cheng)的(de)順利進(jin)行(xing)(xing)。如擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)(ya)墊的(de)使(shi)用(yong)(yong)(yong)溫(wen)度(du)過(guo)(guo)高，因熱(re)膨脹過(guo)(guo)大產(chan)生(sheng)變(bian)形而引起擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)(ya)墊卡(ka)在擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)(ya)筒(tong)(tong)(tong)內(nei)(nei)。為此，擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)(ya)工模(mo)具(ju)在使(shi)用(yong)(yong)(yong)過(guo)(guo)程(cheng)中(zhong)又需要(yao)進(jin)行(xing)(xing)必要(yao)的(de)冷(leng)(leng)(leng)(leng)卻(que)(que)(que)(que)，使(shi)其保持在所要(yao)求(qiu)的(de)溫(wen)度(du)范圍內(nei)(nei)工作。對于(yu)外套內(nei)(nei)襯擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)(ya)墊，擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)(ya)模(mo)和小(xiao)直(zhi)(zhi)徑的(de)芯(xin)(xin)棒一般可(ke)以(yi)采用(yong)(yong)(yong)3~4個(ge)循環(huan)(huan)輪流使(shi)用(yong)(yong)(yong)，必要(yao)時(shi)也可(ke)以(yi)在擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)(ya)結(jie)束后進(jin)行(xing)(xing)水(shui)冷(leng)(leng)(leng)(leng)或噴水(shui)冷(leng)(leng)(leng)(leng)卻(que)(que)(que)(que)。對于(yu)擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)(ya)筒(tong)(tong)(tong)和大直(zhi)(zhi)徑的(de)芯(xin)(xin)棒等大型工模(mo)具(ju)，在使(shi)用(yong)(yong)(yong)過(guo)(guo)程(cheng)中(zhong)吸熱(re)量(liang)大，更(geng)換又不方(fang)便(bian)，故只能(neng)采用(yong)(yong)(yong)專門的(de)冷(leng)(leng)(leng)(leng)卻(que)(que)(que)(que)裝(zhuang)置(zhi)來(lai)進(jin)行(xing)(xing)冷(leng)(leng)(leng)(leng)卻(que)(que)(que)(que)。如擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)(ya)筒(tong)(tong)(tong)的(de)冷(leng)(leng)(leng)(leng)卻(que)(que)(que)(que)方(fang)式(shi)有內(nei)(nei)部(bu)通(tong)水(shui)冷(leng)(leng)(leng)(leng)卻(que)(que)(que)(que)（內(nei)(nei)冷(leng)(leng)(leng)(leng)式(shi)）和內(nei)(nei)襯噴水(shui)冷(leng)(leng)(leng)(leng)卻(que)(que)(que)(que)（外冷(leng)(leng)(leng)(leng)式(shi)）兩種。內(nei)(nei)冷(leng)(leng)(leng)(leng)式(shi)（圖2-42)是(shi)在中(zhong)襯內(nei)(nei)孔表(biao)面加(jia)工有螺旋形冷(leng)(leng)(leng)(leng)卻(que)(que)(que)(que)槽，當(dang)擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)(ya)筒(tong)(tong)(tong)溫(wen)度(du)過(guo)(guo)高時(shi)，通(tong)入水(shui)溫(wen)不低(di)于(yu)60~65℃的(de)冷(leng)(leng)(leng)(leng)卻(que)(que)(que)(que)水(shui)，以(yi)防止過(guo)(guo)冷(leng)(leng)(leng)(leng)引起裂紋，設(she)有電加(jia)熱(re)器與水(shui)冷(leng)(leng)(leng)(leng)卻(que)(que)(que)(que)裝(zhuang)置(zhi)的(de)擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)(ya)筒(tong)(tong)(tong)，如圖2-43所示(shi)；外冷(leng)(leng)(leng)(leng)式(shi)是(shi)當(dang)擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)(ya)循環(huan)(huan)結(jie)束時(shi)，采用(yong)(yong)(yong)環(huan)(huan)狀噴嘴(zui)在擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)(ya)筒(tong)(tong)(tong)一端向筒(tong)(tong)(tong)內(nei)(nei)噴入壓(ya)(ya)(ya)(ya)(ya)(ya)力水(shui)冷(leng)(leng)(leng)(leng)卻(que)(que)(que)(que)，這(zhe)種方(fang)法比(bi)較簡單，但(dan)內(nei)(nei)襯的(de)材(cai)質要(yao)具(ju)有良好的(de)耐(nai)急(ji)冷(leng)(leng)(leng)(leng)急(ji)熱(re)性(xing)(xing)能(neng)。擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)(ya)芯(xin)(xin)棒的(de)冷(leng)(leng)(leng)(leng)卻(que)(que)(que)(que)也有內(nei)(nei)冷(leng)(leng)(leng)(leng)式(shi)和外冷(leng)(leng)(leng)(leng)式(shi)兩種（圖2-44)。