転がり接触疲労によるレール材試験片表面下の集合組織の発達

抄録

Rolling contact fatigue tests were performed on the cylindrical test pieces taken out of a fresh rail, changing the conditions of contact stress, slip rate and velocity. The behavior of plastic deformation was analyzed in terms of the texture development under the contact surface of the test pieces. The results indicated that two kinds of textures developed in the surface layer of the test pieces; one at the topmost surface, especially remarkable in the testing condition without slip, and the other in the layer a half milimeter deep, being caused by Hertz's maximum shearing stress. A slight effect of the velocity was detected such that the former layer got thinner with an increasing velocity. Transmission electron microscopic observations revealed that the texture was formed due to the crystal slip between the pearlite lamellae and its development corresponded to the development of a cell structure between them. The results were also discussed as compared with those of full-size used rails.