Simulation On Solidification Process Of Cu-Cr-M Alloy In Continuous Casting Mold

Nowadays, the demand of high performance copper alloy has increased dramatically.Cu-Cr-M (M=Zr、Mo、Nb、Y、Gd) copper alloy is a class of integrated material with structureand function owing to their high strength, high wear-resistance and high conductive. Copperalloy has a very bright prospects. Cu-Cr-Zr alloy is the most widely used Cu-Cr-M alloy whichis a class of integrated material with high mechanical strength and high conducts electivity.Using the vertical semi-continuous casting to product Cu-Cr-Zr ingot, casting defectsincluding hot tearing, voids and impurities can be found. These problems seriously affectproduction and product quality, restricting the large-scale production Cu-Cr-Zr alloys. Thispaper mainly study the Cu-Cr-Zr ingot above defect causes and control methods throughnumerical simulation methods.The vertical semi-continuous casting of240mm Cu-Cr-Zr cylindrical ingot was takenas the research object. A three-dimensional model describing the vertical semi-continuouscasting of Cu-Cr-Zr cylindrical ingot was established. By the way of thermal-structuralanalysis based on ANSYS, the thermal stress field of the Cu-Cr-Zr cylindrical ingot wasdetermined. Based on the stress field results, the hot crazing behavior was forecasted andanalyzed. The effect of casting temperature and refrigeration strength to the middle crack andcircle crack was also discussed. A two-dimensional model used for flow field simulation wasestablished. The k-ε two equation models were used on the basis of momentum conservationequation，continuity equation and energy conservation equation through FLUENT. By this way,the flow field and solidification conditions under different casting temperature and castingspeed in the mold were acquired. By Analyzing the flow field results, the effect of castingprocess to the void defects and impurity defects was discussed. The effect of castingtemperature and casting speed to the shell thickness was also discussed.The results showed that the crystalline ingot0.025m above the outlet center was easy toform the center of the crack;0.08m above the mold exit at the ingot was easy to form a ringcrack radius of0.05m;0.025m above the mold exit was easy to produce surface cracks.Appropriate to reduce the casting temperature would reduce the cyclic crack; to ensure areasonable cooling intensity could effectively control the formation of a central crack andsurface crack. The simulation results showed that the increase of casting temperature andreduce of refrigeration strength would expand the circulation area in the mold, which was not conductive to the inclusion of bubbles and impurities. The increase of casting temperature andcasting speed would intensify the wave of melt liquid level. The increase of casting speed andcasting temperature would cause the alloy shell at exit of the mold thinning.