Huang Zhifu,Xing Jiandong,He Wei
(School of Material Science and Engineering,Xi'an Jiaotong University,Xi'an ¡¡710049,China)
Abstract:To investigate the effect of thixo-remelting time on the morphologies of initial carbides,semi-solid billets of Cr17 hypereutectic high chromium cast-iron were partially remelted at 1 270¡æ for four distinct periods (5 min, 15 min, 25 min, and 30 min, respectively),and the shape factor and grain factor of carbide grains were characterized quantitatively via a Leica image analyzer.The results indicate that firstly the evolution process of grain morphology during partial remelting undergoes grains melting,spheroidization and refining,and grains growth;secondly,the solute diffusion and interface tension play a predominant role respectively at the primary stage and the middle-final stage in the process of microstructure evolution; finally,the perfect remelting microstructure could be expected to obtain at 1 270¡æ for 15 min in this investigation.
Keywords:hypereutectic high chromium cast iron;thixo-remelting;image analysis;initial carbide