抄録
The bearing used for the axle of Shinkansen train and the #6206 bearing were subjected to a fatigue test, and the V(z) curves were measured by a scanning acoustic microscope. Discussions are made on the detection of bearing damage in terms of residual stress, half-value breadth of X-ray diffraction, by comparing the results of hardness test and metallographic observation (SEM, TEM).
The conclusions are as following;
(1) The variation in sound velocity of elastic surface waves in the measured V(z) curve can be applied for estimation of bearing damage due to fatigue.
(2) When the increase in dislocation is limited, the sound velocity of elastic surface waves corresponds to the variations in residual stress and half-value breadth very well. But when the dislocation increases and a cell structure is formed, the sound velocity tends to drop gradually.
(3) When thermal deformation and large stress develop, the sound velocity of elastic surface wave becomes lower regardless of presence of residual stress.
