• Journal of the Korean Society for Nondestructive Testing
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• v.19 no.4
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• pp.288-293
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• 1999

The integrity of the turbine rotors can be assessed by the coercive force and Vickers hardness of the aged rotors at service temperature. The coercive force measurement system was constructed in order to evaluate material degradation nondestructively. The test specimen was 1Cr-1Mo-0.25V steel used widely for turbine rotor material, and then the seven kinds of specimens with different degradation levels were prepared by the isothermal heat treatment at $630^{\circ}C$. The coercive force of the test materials was measured at room temperature. Vickers hardness and coercive force decreased with the increase of degradation. The relationship between Vickers hardness and coercive force was investigated. The degradation of test material may be determined nondestructively by the relationship between Vickers hardness and coercive force.