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

 美國(guo)PMAC公司的2500噸擠壓(ya)(ya)機推薦的預熱(re)(re)溫(wen)度(du)(du)如下：工具(ju)鋼制作(zuo)的擠壓(ya)(ya)模和穿孔(kong)(kong)頭(tou)為200℃，擠壓(ya)(ya)芯棒(bang)(bang)為250~320℃，擠壓(ya)(ya)筒為260~320℃，穿孔(kong)(kong)筒為360~370℃。擠壓(ya)(ya)模、擠壓(ya)(ya)墊、芯棒(bang)(bang)等小型工模具(ju)的預熱(re)(re)一般(ban)采用箱式(shi)電爐。擠壓(ya)(ya)筒的預熱(re)(re)主要有電阻(zu)加熱(re)(re)和感(gan)應加熱(re)(re)兩種(zhong)。感(gan)應加熱(re)(re)是將感(gan)應線圈放入擠壓(ya)(ya)筒內(nei)進行加熱(re)(re)，加熱(re)(re)時(shi)熱(re)(re)流(liu)由內(nei)襯向外傳導(dao)，擠壓(ya)(ya)簡內(nei)的溫(wen)度(du)(du)分布較(jiao)電阻(zu)加熱(re)(re)合理（圖2-41),因為內(nei)襯、中和外套之間的過(guo)盈(ying)配合應力不會降低，但(dan)感(gan)應加熱(re)(re)時(shi)操作(zuo)不便，感(gan)應圈易損壞，所以目前主要還是采用電阻(zu)加熱(re)(re)。

 在(zai)(zai)正常擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)生(sheng)產(chan)(chan)不(bu)(bu)銹鋼管過(guo)程(cheng)中(zhong)(zhong)，擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)工模(mo)(mo)(mo)具(ju)連續使(shi)用時(shi)，溫度(du)將(jiang)會逐漸升高，而引(yin)起(qi)(qi)工模(mo)(mo)(mo)具(ju)材質高溫回(hui)火，降低了紅硬性，導致工模(mo)(mo)(mo)具(ju)產(chan)(chan)生(sheng)變形(xing)而影響擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)過(guo)程(cheng)的(de)順(shun)利(li)進(jin)(jin)行(xing)。如(ru)擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)墊(dian)的(de)使(shi)用溫度(du)過(guo)高，因熱膨脹過(guo)大(da)產(chan)(chan)生(sheng)變形(xing)而引(yin)起(qi)(qi)擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)墊(dian)卡在(zai)(zai)擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)筒(tong)內(nei)(nei)(nei)(nei)。為此，擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)工模(mo)(mo)(mo)具(ju)在(zai)(zai)使(shi)用過(guo)程(cheng)中(zhong)(zhong)又需要(yao)(yao)進(jin)(jin)行(xing)必(bi)要(yao)(yao)的(de)冷(leng)(leng)(leng)(leng)卻，使(shi)其保(bao)持在(zai)(zai)所(suo)要(yao)(yao)求(qiu)的(de)溫度(du)范圍內(nei)(nei)(nei)(nei)工作。對(dui)于(yu)外(wai)套(tao)內(nei)(nei)(nei)(nei)襯(chen)擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)墊(dian)，擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)模(mo)(mo)(mo)和(he)小(xiao)直(zhi)(zhi)徑的(de)芯(xin)(xin)棒一般可以(yi)采(cai)用3~4個循(xun)環輪流使(shi)用，必(bi)要(yao)(yao)時(shi)也可以(yi)在(zai)(zai)擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)結束后進(jin)(jin)行(xing)水(shui)冷(leng)(leng)(leng)(leng)或噴(pen)水(shui)冷(leng)(leng)(leng)(leng)卻。對(dui)于(yu)擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)筒(tong)和(he)大(da)直(zhi)(zhi)徑的(de)芯(xin)(xin)棒等大(da)型工模(mo)(mo)(mo)具(ju)，在(zai)(zai)使(shi)用過(guo)程(cheng)中(zhong)(zhong)吸熱量大(da)，更換又不(bu)(bu)方便，故只能(neng)(neng)采(cai)用專(zhuan)門的(de)冷(leng)(leng)(leng)(leng)卻裝置來進(jin)(jin)行(xing)冷(leng)(leng)(leng)(leng)卻。如(ru)擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)筒(tong)的(de)冷(leng)(leng)(leng)(leng)卻方式有(you)(you)內(nei)(nei)(nei)(nei)部通(tong)水(shui)冷(leng)(leng)(leng)(leng)卻（內(nei)(nei)(nei)(nei)冷(leng)(leng)(leng)(leng)式）和(he)內(nei)(nei)(nei)(nei)襯(chen)噴(pen)水(shui)冷(leng)(leng)(leng)(leng)卻（外(wai)冷(leng)(leng)(leng)(leng)式）兩種。內(nei)(nei)(nei)(nei)冷(leng)(leng)(leng)(leng)式（圖(tu)2-42)是在(zai)(zai)中(zhong)(zhong)襯(chen)內(nei)(nei)(nei)(nei)孔表面(mian)加(jia)工有(you)(you)螺旋形(xing)冷(leng)(leng)(leng)(leng)卻槽，當擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)筒(tong)溫度(du)過(guo)高時(shi)，通(tong)入水(shui)溫不(bu)(bu)低于(yu)60~65℃的(de)冷(leng)(leng)(leng)(leng)卻水(shui)，以(yi)防止過(guo)冷(leng)(leng)(leng)(leng)引(yin)起(qi)(qi)裂紋，設有(you)(you)電加(jia)熱器與(yu)水(shui)冷(leng)(leng)(leng)(leng)卻裝置的(de)擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)筒(tong)，如(ru)圖(tu)2-43所(suo)示；外(wai)冷(leng)(leng)(leng)(leng)式是當擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)循(xun)環結束時(shi)，采(cai)用環狀(zhuang)噴(pen)嘴在(zai)(zai)擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)筒(tong)一端向(xiang)筒(tong)內(nei)(nei)(nei)(nei)噴(pen)入壓(ya)(ya)(ya)(ya)(ya)力水(shui)冷(leng)(leng)(leng)(leng)卻，這種方法比較簡單(dan)，但內(nei)(nei)(nei)(nei)襯(chen)的(de)材質要(yao)(yao)具(ju)有(you)(you)良好的(de)耐急冷(leng)(leng)(leng)(leng)急熱性能(neng)(neng)。擠(ji)(ji)(ji)(ji)(ji)壓(ya)(ya)(ya)(ya)(ya)芯(xin)(xin)棒的(de)冷(leng)(leng)(leng)(leng)卻也有(you)(you)內(nei)(nei)(nei)(nei)冷(leng)(leng)(leng)(leng)式和(he)外(wai)冷(leng)(leng)(leng)(leng)式兩種（圖(tu)2-44)。