Characterization of Solidification Structure Morphology in High-Carbon Steel Billet by Fractal Dimension

摘要

High-carbon steel is one of the typical high-end steels, and its solidification morphology has great influence on the quality of steels. In this work, fractal dimension was introduced to describe solidification structure morphology in 82B cord steel billet with 0.82 wt% carbon content. Fractal dimension was calculated using box-counting method (D_(Box)), sandbox method (D_(Sand)), and branching method (D_(Bran)). It was demonstrated that the fractal dimension is effective to characterize quantitatively the complexity of solidification structure morphology. The value of fractal dimension calculated by the above three methods is not the same as different calculation methods describe solidification structure characteristics from different angles. In addition, the relationship between fractal dimension and secondary dendrite arm spacing (SDAS) and segregation area ratio (R_(seg)) was discussed. Fractal dimension calculated by box-counting method was well correlated with SDAS and R_(seg). This result demonstrated box-counting method can better reflect solidification characteristics of the billet than sandbox method and branching method.