Application of Multi-microprobe DC Potential Difference Method to Residual Life Prediction in High-temperature Fatigue of Austenitic Stainless Steel: FEM Analysis of Effects of Spacing between Probe Pins and Scan Interval

Abstract

The present authors have proposed a new DC potential method using multi-microprobes and showed that the method can successfully make the residual life estimation for high temperature fatigue of an austenitic stainless steel JIS SUS316L at high temperatures of 765 to 923 K where multiple-site small cracks cause fatigue fracture. In order to clarify the effects of spacing between probe pins and scan interval on the potential difference measurement, the present paper has performed FEM steady-state current analyses as well as experimental analyses and showed that the spacing between probe pins brings about larger standard deviation and the same mean value of the potential difference distributions measured whereas that the two levels of the scan intervals investigated here give the same values of the mean and the standard deviation. This implies that the proposed method is robust and is not so affected by the probepin spacing and the scan interval.