Comparative analysis was conducted to illustrate the effect of high-temperature reduction pretreatment on the internal quality of 42CrMo casting billet. Analysis of macrostructure clarifies that reduction pretreatment could reduce the size of central cavities and equiaxed crystals and improve the segregation degree and porosity on statistics. Lath bainite matrix and granular structure on segregation bands mainly dominate the microstructure of original billet, while pro-eutectoid ferrite and its accompanying troostite are added due to the application of reduction pretreatment. Additionally, C, Mn, and Mo are suggested to be enriched in segregation bands where pores and inclusions tend to be generated. By clarifying the microstructure evolution during cooling process, physical compression and multiplication of prior austenite grain boundaries caused by recrystallization are regarded as the main reasons in improving the internal quality of 42CrMo billet.

进行了比较分析，以说明高温还原预处理对42CrMo铸坯内部质量的影响。宏观结构分析表明，还原预处理可以减小中心腔和等轴晶体的尺寸，并从统计学上改善偏析度和孔隙率。板条贝氏体基体和偏析带上的颗粒结构主要控制原始坯料的微观结构，而共还原铁素体及其伴随的钙钛矿则由于采用还原预处理而添加。另外，建议C，Mn和Mo富集在偏析带中，在偏析带中容易产生孔和夹杂物。通过澄清冷却过程中的微观结构演变，