极值分析法在SCM435钢夹杂物尺寸分析中的应用

Application of extreme value analysis method to inclusion size analysis of SCM435 steel

应用ASTM E2283中极值分析的标准化方法(最大似然估计法),对汽车标准件用钢SCM435轧材试样横截面夹杂物尺寸分布进行统计分析。结果表明:汽车标准件用SCM435钢最大尺寸夹杂物成分均为CaO-Al_(2)O_(3)类型,夹杂物形貌呈球状;采用极值分析Gumbel概率分布曲线与实际夹杂物尺寸吻合度较好,推测累计概率P=0.999时预测的夹杂物最大尺寸为39.30μm;增加夹杂物尺寸检测的数据个数并未显著改变夹杂物尺寸分布规律,两者推测的夹杂物最大尺寸相差不大。

To statistically analyze cross-section inclusion size distribution of steel SCM435 rolled sample for automotive standard parts with standardized method of extreme value analysis(maximum likelihood estimation method) in ASTM E2283. Results show that the largest size inclusions of SCM435 steel for automotive standard parts are CaO-Al_(2)O_(3), and the morphology of inclusions is spherical;The Gumbel probability distribution curve by extreme value analysis is in good agreement with actual inclusion size. It is speculated that maximum inclusion size predicted when cumulative probability P= 0.999 is 39.30 μm. Increasing the number of inclusion size detection data does not significantly change the distribution law of inclusion size, and the inferred maximum inclusion size is almost the same.