Patent ID: 9488618
Filing Date: 2016-11-08
CPC Classification: G01N,H02K

Claim Text:
1. A method for non-destructive evaluation of one or more of yield strength, toughness, or tensile ductility physical properties of monolithic material forming a generator retaining ring, which property is altered by temperature change in the material that results from thermal exposure of the ring, comprising: providing a generator ring constructed of a monolithic, solid metal material; measuring the provided generator ring's International Annealed Copper Standard (IACS) electrical conductivity with an eddy current test system, at a single test frequency; obtaining reference data sets for test samples of the same monolithic, solid metal material, which are generated by: heating separate, plural, respective test samples, of the same monolithic material, to respective desired different temperatures for a common exposure period, and thereafter allowing each sample to cool to ambient temperature, measuring, for each respective cooled test sample, its IACS electrical conductivity, at the same single frequency, and one or more of its yield strength, toughness or tensile ductility physical properties; comparing the provided generator ring's measured IACS electrical conductivity to the reference data set's measured IACS conductivities of the test samples, and deriving, for the provided generator ring, one or more of its yield strength, toughness or tensile ductility physical properties or its prior thermal exposure temperature, based on its measured electrical conductivity and corresponding electrical conductivity/physical property information in the reference data set; and evaluating whether at least one of the provided generator ring's yield strength, toughness or tensile ductility physical properties, which is derived from the test data set, is acceptable for use in a generator.