硬度法测定渗氮层深度结果的测量不确定评定及分析

主要以综合评定法对硬度法测定渗氮层深度结果的测量不确定度来源进行了分析，分别讨论了硬度法测定总渗氮层和有效渗氮层深度由于界限硬度值要求不同，导致引入的标准不确定度分量不同，并对每个标准不确定度分量进行了评定。结果表明：在相同试验条件和方法下，硬度法测定总渗氮层深度结果测量不确定度明显小于硬度法测定有效渗氮层深度结果测量不确定度。其原因在于试验测定结果重复性引入的标准不确定度分量是硬度法测定总渗氮层深度结果测量不确定度主要来源；而硬度法测定有效渗氮层深度结果测量不确定度主要来源却是由计算模型中插入的界限硬度值引入的。另外，采用硬度法测定深度，应注意硬度计工作台移动的分度值和垂直度偏差对测量结果的影响。

Evaluation of Measurement Uncertainty for Nitrided Case Depth with Hardness Method

The sources of measurement uncertainty for nitrided case depth with hardness method are analyzed. Moreover, the measurement uncertainty of nitrided case depth is evaluated in detail by synthetic evaluation method. The influences of boundary Vickers hardness value on evaluation of measurement uncertainty for nitrided case depth with hardness method are emphasized in the study. The results show that measurement uncertainty of the whole nitrided case depth is significantly less than the effective nitrided case depth in the same test condition and method. The reason is that the uncertainty component introduced by test repeatability of measurement results is the main sources for the whole nitrided case depth measurement uncertainty; however, the main sources for the effective nitrided case depth measurement uncertainty are introduced by the boundary Vickers hardness values. The influence of indexing table and verticality deviation movement on the measurement results should be considered when evaluating measurement uncertainty for nitrided case depth with hardness method.