International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

During operation, under the influence of mechanical stress, temperature, and external environment, the initial structure of a railway wheel undergoes changes that lead to its fatigue-corrosion wear.
The wheels with different tread profiles that were removed from operation due to the maximum wear of the rims were studied. The studies were carried out using the metallographic method (Neophot-21) and scanning electron microscope JSM-35.
The causes of cracks and wear particles formation near the tread surface of railway wheels associated with phase and structural changes occurring during operation were analyzed. The possibilities of changing the tread profile due to uneven wear were established. It was shown that structural and phase changes near the tread surface are associated with the development of plastic shifts due to the action of external loads, thermal stresses during braking, and the formation of “white layers” when the metal is heated by the heat of braking and abrupt cooling when the brakes are turned off. The role of non-metallic inclusions and corrosion products of wheel steel in the formation of cracks near tread of railway wheels has been established.

Some wheel steels inclined for the self-quenching on bainite structure were produced and investigated after hot deformation and heat strengthening. Steels contained 0,12…0,45% of carbon, and also Si, Mn, Mo, Cr, Ni, V, Ti, Al. Steels with bainite structure after hot deformation and tempering were investigated. It was shown the possibility of the railway wheels production with bainite structure and hardness of 400HB without heat strengthening treatment. The results of investigation shown the possibility of railway wheels production with bainite structure, hardness of 400 HB and high complex of the mechanical and operating properties without heat strengthening treatment. These tasks solved owning to application of new wheel steels and up-to-date technology.

Causes of wear particles formation on railway wheels tread were investigated. Structural factors connecting with plastic deformation, formation of “white layer”, and also with non-metallic inclusions and corrosive products of wheel steel, defining wear of railway wheels tread during operation were fixed. Repeating heat-mechanical action on railway wheel tread by interaction between wheel and rail promotes incandescence of stresses and defects (microcracks, separations) that promote wear particles formation having different shape, source and mechanism of nucleation. Results of analysis of microcracks, spalles and wear particles and also of mechanisms of their formation was shown that wear of railway wheel tread is very composite phenomenon. It passes by few mechanisms (fatigue, adsorbtional, corrosive, under friction) and is multifactors process.