基于图像处理方法的局部低硬度P91弯头蠕变寿命评估

Creep Life Assessment of Local Low Hardness P91 Elbow Based on Image Processing Method

以某电厂管道普查中发现的局部低硬度P91弯头为研究对象,一方面,通过网格化的硬度检测和数据采集,利用图像处理方法分割出该弯头的低硬度区域,然后经有限元计算求得低硬度区域的最大应力;另一方面,根据现场的硬度、金相检测结果,通过查阅相关文献,求得同等级硬度下的持久强度,最终通过等温线外推法计算该弯头的剩余寿命。对于局部低硬度P91,这种基于图像处理方法的蠕变寿命评估手段可实现精确的Ⅱ级寿命评估,为广大电厂处理局部低硬度P91问题提供了一种思路,对在役机组局部低硬度P91的寿命管理有指导意义。

The local low hardness P91 elbow found in the pipeline survey of a power plant was taken as research object.On the one hand,through grid-based hardness testing and data acquisition,the low hardness area of the elbow is divided by image processing method,and then the maximum stress in the low hardness area is obtained by finite element calculation.On the other hand,according to the on-site hardness and metallographic test results,by referring to relevant literature,the lasting strength of the same grade hardness is obtained,and finally the remaining life of the elbow is calculated by isotherm extrapolation method.For local low hardness P91,the creep life assessment method based on image processing method can achieve accurateⅡgrade life assessment,which can provide a way of thinking for the general power plants to deal with local low hardness P91 problems,which also has certain guiding significance for the life management of local low hardness P91 in service units.