METHOD FOR MEASURING RESIDUAL OF MATERIAL AND METHOD AND DEVICE FOR RELEASING RESIDUAL STRESS USED THEREFOR

摘要

PROBLEM TO BE SOLVED: To simplify the working step of residual stress measurement using a stress releasing method by electric discharge machining and, at the same time, to improve the accuracy of the measurement. SOLUTION: An opening for leading out the lead wire 4 of a wire strain gauge 2 is formed through a cylindrical electric discharge machining electrode 1 and the strain gauge 2 is stuck to a material 3 by keeping the lead wire 4 connected to a stress measuring instrument. In such a state, a groove is dug into part of the material 3 around the gauge 2 with the electrode 1 and the stress of the part of the material carrying the stuck gauge 2 is released in the groove. Then the value measured by means of the strain gauge 2 after the stress is released is read on the strain measuring instrument 7.