强制风冷在大型铸钢件砂芯上的应用

发布时间：2018-07-22 14:25

【摘要】：通过活动横梁铸件简化模型研究了冷铁、自然风冷和强制风冷对厚壁回转体大型铸钢件凝固时间和砂芯温度场的影响。砂芯采用强制风冷铸件凝固时间最短,而采用冷铁不能缩短铸件凝固时间。通过对比不同冷却条件砂芯的温度场发现无强制冷却砂芯和冷铁砂芯分别在13 h和12 h出现热饱和现象,随后砂芯中心到铸件的温度梯度转为负值,砂芯向铸件输送热量;而砂芯采用自然风冷和强制风冷时从砂芯中心到铸件建立了正的温度梯度,能有效吸收铸件凝固期间释放的热量而改善其冷却条件;强制风冷对流换热系数高,冷却作用明显。对活动横梁铸件原始工艺改进,砂芯采用强制风冷;模拟结果与原始工艺相比缩孔位置上移,表明冒口补缩能力增强;同时砂芯实测温度场与模拟温度场相吻合,验证了模拟结果的可行性,由于砂芯在高温热作用下的时间短,经改进工艺所生产的活动横梁铸件中心孔表面无机械粘砂。
[Abstract]:The effects of cold iron, natural air cooling and forced air cooling on solidification time and temperature field of thick wall rotary large steel castings were studied by simplified model of movable beam castings. The solidification time of sand core is the shortest by forced air cooling casting, but the solidification time can not be shortened by cold iron. By comparing the temperature field of the sand core with different cooling conditions, it is found that the heat saturation phenomenon occurs in the sand core without forced cooling and the cold iron core at 13 h and 12 h, respectively, and then the temperature gradient from the center of the sand core to the casting becomes negative, and the core transmits heat to the casting. When the sand core is naturally air-cooled and forced air-cooled, a positive temperature gradient is established from the center of the sand core to the casting, which can effectively absorb the heat released during solidification and improve the cooling conditions, and the forced air-cooled convection heat transfer coefficient is high and the cooling effect is obvious. The original process of the movable beam casting is improved, the sand core is forced air-cooled, the position of the shrinkage hole is moved up by the simulation results compared with the original process, which indicates that the riser feeding ability is enhanced, and the measured temperature field of the sand core coincides with the simulated temperature field. The feasibility of the simulation results is verified. Due to the short time of the sand core under high temperature and heat, there is no mechanical sand on the surface of the center hole of the movable beam castings produced by the improved technology.
【作者单位】：沈阳工业大学材料科学与工程学院;沈阳铸锻工业有限公司铸钢分公司;
【基金】：沈阳市科技计划资助项目(F13-036-2-00)
【分类号】：TG242

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