レール鋼の転がり接触疲労過程における集合組織の発達

抄録

Rolling contact fatigue tests are performed by using cylindrical test pieces taken out of rail, under conditions of slip ratio 0%, Hertz' contact stress 1.2GPa, velocity 60km/hr and water lubrication. The behavior of plastic deformation below the contact surface of the test piece is analyzed with an X-ray device and a transmission electron microscope. The results indicate that the dislocation density increases, while a preferred orientation texture and a cell structure emerge in the contact surface layer with an increase in the number of cycles of rolling contact fatigue. Slip deformation of crystal is accelerated further when fatigue progresses to a number of cycles larger than a specific value and then so called “shelling” grows with a remarkable development of the texture in either the rail or the wheel.