Niyama判据预测大型铸钢件旋回破碎机横梁缩孔缩松缺陷

Prediction of Shrinkage and Porosity of Crossbeam Used for Large Scale Steel Casting Gyratory Crusher by Niyama Criterion

针对大型铸钢件旋回破碎机横梁在铸造生产过程中存在的缺陷问题,利用Pro CAST模拟软件,对特大型旋回破碎机横梁铸件进行了凝固过程的数值模拟,分析了横梁纵向剖面8个关键位置的温度变化曲线,归纳出冷却速率的变化趋势。同时根据Niyama判据预测铸件中产生缺陷的位置。在此基础上,对原铸造工艺方案进行改进,即在发热冒口的底部添设补贴。经过模拟结果对比表明:改进后的工艺有效的增加了冒口补缩距离,Niyama判据满足不形成缩松缩孔的临界值要求。避免了在铸造时缩松缩孔缺陷的产生。模拟实验结果与实际生产相符。

By observation on the defects existed in the large scale steel casting gyratory crusher, the solidification process of the large scale steel casting gyratory crusher was simulated by Pro CAST simulating software. The temperature changing curves of eight key positions were analyzed and the changing trend of cooling rate was summarized. The positions of the defects were predicted by Niyama criterion. The original casting technique was improved by adding subsidies at the bottom of exothermic riser. The simulation results show that the improved casting technology can effectively increase the feeding distance of the riser, and the Niyama criterion is satisfied with the critical value of not formatting the shrinkage and porosity defects. Therefore it avoided the formation of shrinkage and porosity defects in the casting process. Simulation experiment results are in conformity with the actual production results.