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控制钢中第二相粒子(包括非金属夹杂物和碳氮化物)的形貌对降低非金属夹杂物的危害、提高钢材力学性能等具有重要作用。本工作通过引入Jackson a指数建立了钢中第二相粒子形貌的预测理论模型,指出钢中第二相粒子形貌由其熔化熵、生长方向和温度(过冷度)决定。通过非水溶液电解的方法和室温有机溶液包埋(RTO)技术,结合SEM分析了4个钢种各类夹杂物的三维形貌以及其内部特征,实测的第二相粒子形貌与理论预测一致。理论和实验观察结果均证明,当第二相粒子Jackson a指数大于3时,其形貌为小面状;Jackson a指数小于2时,呈非小面状。
Controlling the morphology of the second phase particles (including non-metallic inclusions and carbonitrides) in the steel plays an important role in reducing the damage of non-metallic inclusions and improving the mechanical properties of the steel. In this work, the prediction model of the second-phase particle morphology in steel was established by introducing the Jackson a-index. The morphology of the second-phase particles in the steel was determined by its melting entropy, growth direction and temperature (supercooling degree). The three-dimensional morphology and internal characteristics of all kinds of inclusions in four steel grades were analyzed by non-aqueous electrolytic method and RTM technique combined with SEM. The measured second-phase particle morphology was consistent with the theoretical prediction . Both theoretical and experimental observations show that when the Jacksona index of the second-phase particles is larger than 3, the shape of the second-phase particles is faceted. When the Jacksona index is less than 2, the shape is non-faceted.