讨论了目前对金属材料规定非比例延伸强度Rp0.2的不确定度评定的局限性,通过分析GB/T 228-2002中非比例延伸力值的确定过程,将引伸计标距引入的不确定度、引伸计测量引入的不确定度和基准线确定引入的不确定度三个不确定度分量统一到一个模型中,并合成为由引伸计引入的标准不确定度,从而解决了目前对引伸计引入的三个不确定度分量没有数学模型的问题,确定了新的Rp0.2不确定度评定方法,并运用到实例中进行了计算。

The current limitations of uncertainty evaluation for the proof strength at non-proportional extension Rp0.2 of metallic materials were discussed. By analyzing the process of determining the non-proportional elongation force value in the standard GB /T 228-2002, three uncertainty components which were introduced by extensometer gauge length and extensometer measurement and base line determination were unified into a single model, combined into the standard uncertainty introduced by extensometer. The problem of that there was no mathematical model in three uncertainty components evaluation introduced by extensometer was solved. The new uncertainty evaluation method for Rp0.2 was established. And the uncertainty of an example was calculated by the method.