借助于扫描电镜分析和显微硬度测试等方法，对滚珠丝杠用GCr15轴承钢在不同热处理条件下的等温球化退火效果进行了研究，并通过定量金相的方法，分析统计了不同热处理工艺参数条件下碳化物的形貌及其分布。结果表明:GCr15轴承钢在790 ℃奥氏体化、冷却速率为20 ℃·h-1的条件下球化退火后，其硬度分布最均匀，球化退火效果最好；此时碳化物平均粒径标准差最小,平均长短轴比值不大于2.1，颗粒圆度不小于0.17，粒径为0.5~1.1 μm的碳化物所占百分比约为50%。该方法可定量评定GCr15轴承钢的球化质量级别，对实际生产有一定的指导意义。

The isothermal spheroidizing annealing effect with different temperatures and cooling rates was investigated by SEM analysis and hardness test, and the morphology and distribution of the carbide under different process parameters were analyzed by quantitative metallography methods. The results show that the hardness distribution was most uniform and the spheroidizing annealing effect was best when the GCr15 bearing steel was austenitized at 790 ℃ and cooling at 20 ℃·h-1. In this case, the standard deviation about average particle diameter of carbide was the minimum, the ratio of the major axis and minor axis was not greater than 2.1, the particle roundness was not less than 0.17, and percentage of 0.5~1.1 μｍ carbide was about 50%. This method can provide some references to accurately and quantitatively evaluate the spheroidizing annealing effect of GCr15 bearing steel, and it is significant for practical production.