以ER8车轮钢为对象，采用预处理＋终处理方法改善车轮组织状态，并分析了工艺参数对晶粒尺寸及分布的影响。结果表明：经过870℃×1．5h预处理＋840℃×1．5h终处理，晶粒平均尺寸及分布均匀性明显改善，断裂韧性得到显著提高；在保温1．5h的终处理中，900℃时异常晶粒快速长大，平均晶粒尺寸出现局部峰值；随着初始组织均匀性的提高，异常晶粒尺寸与正常晶粒尺寸相对差（RD）达到峰值的温度有提高趋势。
A new heat treatment process involving a pre-treatment and a final treatment had been proposed to improve the microstructure of ER8 wheel steel. Effect of the process parameters on average grain size and grain size distribution was studied. The results show that after a pretreatment of 870 ℃ × 1.5 h and a final treatment of 840 ℃ × 1.5 h, the average grain size of the wheel is decreased and the heterogeneity of grain size distribution is improved significantly, and the fracture toughness increased evidently. During the final treatment at 900℃ for 1.5 h, the abnormal grain size grows rapidly and the average grain size reaches a local peak. The temperature corresponding to the maximum relative difference between the abnormal and normal grain size （RD） increases with the improving of the heterogeneity of prior austenite grain size.
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