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利用有限元分析软件对铸钢叶轮淬火过程进行模拟,分析工件在结构改进前淬火过程中的温度场和应力场的变化情况,直观得到淬火工件内部的温度及应力变化规律。结构改进前,温度的最大值自始至终集中在叶轮轴端的内部厚大处,此处与相对应的表面在冷却过程中的温度下降速率存在较大差异,导致淬火后叶轮轴端外表面处存在较大热应力进而可能引起叶轮开裂。模拟分析表明:在保持其它条件不变的情况下,对叶轮的结构进行优化改进。改进后模拟结果显示,叶轮轴端内部的厚大处温度下降明显,内外表面的温度差明显缩小,最大应力则出现在叶片与前盖板的倒角处,且应力值与改进前相比明显降低,淬火开裂倾向大大减轻。经生产实际验证,改进后的叶轮未出现开裂现象。
The finite element analysis software was used to simulate the quenching process of the cast steel impeller. The temperature field and stress field of the workpiece during the quenching process before the structural improvement were analyzed. The temperature and stress variation inside the quenched workpiece were obtained visually. Before the structural improvement, the maximum temperature is concentrated in the thick inside of the impeller shaft end, there is a big difference between the cooling rate and the corresponding surface temperature drop rate, resulting in quenching after the impeller axial end of the surface there is more Large thermal stress may in turn cause cracking of the impeller. Simulation analysis shows that the structure of the impeller is optimized and improved while keeping other conditions unchanged. The simulation results show that the temperature inside the large axial part of the impeller decreases obviously, the temperature difference between the inner and outer surfaces decreases obviously, and the maximum stress appears at the chamfer between the blade and the front cover, and the stress value is obviously higher than before Reduce, greatly reduce the tendency of quenching and cracking. After the actual production verification, improved impeller cracking phenomenon does not appear.