CRACK EVALUATION CRITERION FORMULATION METHOD, CRACK EVALUATION METHOD BY INTERNAL FLAW DETECTION, AND MAINTENANCE METHOD

摘要

To provide a crack evaluation criterion formulation method and crack evaluation method by internal crack detection, capable of evaluating an internal state of a metal material in an initial step of a crack growth process.SOLUTION: The crack evaluation criterion formulation method according to at least one embodiment of the present invention is a crack evaluation criterion formulation method for formulating crack evaluation criteria, the method including the steps of: creep-deforming a test piece to a first time point; performing internal flaw detection of the test piece in at least one second time point before the first time point to acquire a flaw signal in the at least one second time point; and comparing an estimated size of the crack in the second time point obtained by tracing back the crack growth process from the first time point to the at least one second time point, with the flaw signal in the second time point to determine the evaluation criteria by the internal flaw detection.SELECTED DRAWING: Figure 1