【摘要】 系统研究了在K417高温合金真空熔铸过程中施加由工频交流电磁场和恒稳直流电磁场组成的复合电磁场对高温合金铸锭凝固组织的影响。实验结果表明:在浇注完毕后同时施加60 A旋转电磁场和290 A恒稳直流电磁场的工艺条件下,由于恒稳直流电磁场在金属液面处产生的电磁制动效应可以抑制施加旋转电磁场所引起的金属液面的波动,不仅避免了因金属液面波动太大而使铸锭缩孔恶化的情况出现,而且大幅提高了旋转电磁场在金属液凝固过程中的作用范围和效果,最终得到细小等轴晶比例达到96%、缩孔明显改善的优质高温合金铸锭。更多还原

【Abstract】 The effect of multi-electromagnetic field on the K417 superalloy ingots solidification microstructure has been studied.The results show that during the solidification process of superalloy vacuum casting,the application of the multi-electromagnetic field,composed of rotary electromagnetic field with 60 A current and steady DC electromagnetic field with 290 A current,can increase the scope and effect of rotary electromagnetic field as well as improve the feeding conditions of ingots.The reason can be attributed to that the electromagnetic brake generated by DC electromagnetic field can suppress effectively the metal surface fluctuation generated by rotary electromagnetic field.As a result,the fine equiaxed grain fraction of ingots can be increased to 96 % and the shrinkage porosity of ingots can be greatly reduced.更多还原