InconelX-750合金大型电渣锭重熔过程的模拟

Simulation of remelting process of InconelX-750 alloy large electroslag ingot

利用MeltFlow模拟软件对大型InconelX-750合金电渣锭铸态组织的一次、二次枝晶间距进行模拟计算,并对实际生产的电渣锭取样进行显微组织观察。模拟计算结果表明:不同合金元素对冷却速率和局部凝固时间的变化敏感程度不同,但是在整个电渣锭范围内分布均匀,无明显宏观偏析;由电渣锭头部向尾部、中心位置到边缘,一次、二次枝晶间距逐渐减小,在相同位置,电渣锭头部的枝晶间距大于尾部。实验结果表明:电渣锭由中心位置到边缘,随着凝固过程中过冷度的增加,枝晶组织尺寸和枝晶端部曲率半径逐渐减小,且中心位置的一次枝晶间距大约是边缘位置的1.9~2.4倍,中心位置二次枝晶间距大约是边缘位置的1.4~1.6倍。相同位置,电渣锭头部的枝晶组织尺寸和枝晶间距大于尾部;电渣锭头部试样枝晶间析出大量针状相,而尾部仅有少量的块状相弥散析出;枝晶间距模拟计算结果和实验测量结果基本一致,可以利用该模拟软件对电渣锭凝固之后的枝晶间距进行预测。

The primary and secondary dendrite spacing of as-cast microstructure of large-scale InconelX-750 alloy electroslag ingot was simulated by MeltFlow simulation software, and the microstructure of the actual produced electroslag ingot was observed. The simulation results show that the different alloy elements have different sensitivity to the change of cooling rate and local solidification time, but they are uniformly distributed in the whole range of electroslag ingot without obvious macroscopic segregation. From the head of the electroslag ingot to the end, the center position to the edge, the primary and secondary dendrite spacing gradually decreases, at the same position, the dendrite spacing at the head of the electroslag ingot is larger than that of at the end. The experimental results show that from the center position to the edge of the electroslag ingot, with the increase of undercooling during solidification, the dendrite structure size and the radius of curvature of the dendrite tip gradually decrease, and the primary dendrite spacing at the center position is about 1.9-2.4 times of that at the edge position, and the secondary dendrite spacing at the center position is about 1.4-1.6 times of that at the edge position. At the same position, the dendrite structure size and the dendrite spacing of the head of the electroslag ingot are larger than that of the end;a large number of needle-like phases are precipitated between the dendrites in the head of the electroslag ingot, but only a small amount of bulk phase is uniformly precipitated in the end. The results of simulation and experimental measurement of the dendrite spacing are basically the same, which indicates the simulation software can be used to predict the dendrite spacing of the electroslag ingot after solidification.