Effect of TiB2 particle size on refinement of aluminum cast structure by addition of Al-Ti-B grain refiner

The casting defects such as shrinkage porosities and hot tears are reduced by grain refinement in cast products. The Al-Ti-B grain refiner is added to the molten aluminum during casting process to achieve the fine grain structure. The Al-Ti-B grain refiner shows good grain refinement effectiveness, however the risk of increase the inclusions involve. Therefore, it is required to reduce the usage of grain refiner. The optimization of the usage of grain refiner is difficult, because the inoculation efficiency fluctuates with the manufacturer, content and lots. Free growth model, which is proposed by Greer, suggested the TiB2 particle size distribution is one of factors that change the inoculation efficiency. On the other hand, the effect of particle size distribution have not been verified in experimentally and calculation by using multiple grain refiners. In this study, a grain size prediction model was developed to clarify the cause of variation of inoculation efficiency. The calculation results were compared with experimental data which was obtained by TP1 test. © 2021 The Japan Institute of Light Metals