Fig. 1 shows the dimensions of the sample and the fretting pad. After processing of the sample and the fretting pad, 1 #, 2 #, 3 #, 4 # SiC sandpapers were used in sequence to polish the gauge section of the sample and the fretting pad contact surface, in which polishing direction is along the axial direction of the sample. The polished surface roughness (Ra) was no more than 0.16.