分别采用YB/T 5338-2006规定的方法和Rietveld全谱拟合方法对常规GCr15钢中的残余奥氏体含量进行了定量分析, 发现两种方法所得结果十分相近, Rietveld 全谱拟合方法具有准确、方便和快捷等优点, 可作为用X射线衍射仪进行残余奥氏体定量测定的有益补充。进而对于X射线衍射峰强度比值不符合YB/T 5338-2006要求的某GCr15粉末冶金失效零件试样, 采用Rietveld全谱拟合方法进行了残余奥氏体含量的定量测定, 得到其残余奥氏体含量高达19.09%(质量分数),远远超过了正常值, 这可能是导致该零件失效的原因之一。

The content of retained austenite in normal GCr15 steel was measured by X-ray diffractometer according to YB/T 5338-2006 and by the way of Rietveld refinement of X-ray data and nearly the same results were obtained. It was found that the Rietveld refinement method has some advantages such as time saving, convenience and data accuracy. Therefore, it is a useful way to quantify the retained austenite according to the X-ray diffraction data. Then the Rietveld refinement method was applied to the quantitative determination of the retained austenite in a failed sample of GCr15 powder metallurgy part. The way of YB/T 5338-2006 was ineffective because the intensity ratio of its X-ray diffraction peaks was out of that specified by YB/T 5338-2006. It was shown that more retained austenite with mass percentage of 19.09% existed in the part, which may be one of the failure reasons of the GCr15 powder metallurgy part.