Degradation evaluation method for heat resistant steel and degradation evaluation method for turbine

摘要

PPROBLEM TO BE SOLVED: To provide a method of noncontactly determining a creep damage and an embrittlement as a thermal damage generated in a heat-resistant steel, especially a high Cr steel, and evaluating a degradation in the heat-resistant steel, and to provide a method of evaluating degradation in a turbine using the method. PSOLUTION: The method of evaluating degradation in the heat-resistant steel calculates an area ratio of a deposition generated on a surface of the heat-resistant steel to be inspected, and determines the degree of the embrittlement in the heat-resistant steel from the area ratio of the deposition generated on the surface of the heat-resistant steel on the basis of a previously-created graph for indicating a correlation between an embrittlement index and the area ratio of the deposition generated in the heat-resistant steel. The degradation evaluation method calculates a number concentration of voids generated on the surface of the heat-resistant steel, normalizes it by use of the multiaxial degree of the heat-resistant steel, and determines the degree of the creep damage in the heat-resistant steel from a value as the number concentration of the voids generated on the surface of the heat-resistant steel normalized by the multiaxial degree on the basis of a previously-created graph for indicating a correlation between a lifetime ratio of the heat-resistant steel and the number concentration of the voids normalized by the multiaxial degree. PCOPYRIGHT: (C)2009,JPO&INPIT