Damage assessment of 30Cr1Mo1V rotor steel based on the misorientation parameters during high-temperature fatigue process

This article reports the fatigue damage assessment of 30Cr1Mo1V rotor steel using the misorientation parameter method. During the high-temperature fatigue process, the average misorientation parameters such as KAMave, GRODave, and GNDave presented an overall increasing tendency. KAMave and GNDave increased smoothly, but GRODave displayed a non-monotonic and oscillatory change. The decrease of GROD value in the early fatigue stages could be due to the effect of applied stress on grains, which results in a "constraint" effect and leads to lattice rotation toward a certain direction. Since KAMave increased obviously (i.e., 27.85%) in the 0%-60% Df fatigue stage, while GRODave increased the most (i.e., 96.85%) in the 80%-100% Df stage. Therefore, a mixed parameter assessment method is proposed to assess fatigue damage of 30Cr1MolV steel by combining these two parameters.