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大型铸件在铸造和机加工过程易产生残余应力,为了减小HT250灰铸铁机床用铸件的残余应力,对不同退火工艺下铸件的残余应力进行了测试。结果表明,在保温时间4 h和出炉温度300℃下,合适的退火温度为650℃;在退火温度650℃和出炉温度300℃下,合适的保温时间为4 h;在保温时间4 h和退火温度650℃下,合适的出炉温度为200℃。在退火温度650℃,保温时间4 h,出炉温度200℃时,HT250灰铸铁的残余应力消除得较好。
Large castings are prone to residual stresses in the casting and machining processes. In order to reduce the residual stress of castings for HT250 gray cast iron machine tools, the residual stress of castings under different annealing processes was tested. The results showed that the suitable annealing temperature was 650 ℃ at the holding time of 4 h and the casting temperature of 300 ℃. The suitable holding time was 4 h at the annealing temperature of 650 ℃ and the firing temperature of 300 ℃. After the holding time of 4 h and annealing Temperature 650 ℃, the appropriate tapping temperature of 200 ℃. When the annealing temperature is 650 ℃, the holding time is 4 h and the temperature is 200 ℃, the residual stress of HT250 gray cast iron is better eliminated.