Siberian State Industrial University, Novokuznetsk, Russia

V. E. Gromov, Dr. Phys.-Math., Prof., Head of the Dept. of Natural Sciences named after professor V. N. Finkel, e-mail: gromov@physics.sibsiu.ru
S. V. Konovalov, Dr. Eng., Prof., Head of the Dept. of Mechanics and Mechanical Engineering, e-mail: konovalov@sibsiu.ru
M. A. Porfiryev, Postgraduate Student of the Dept. of Natural Sciences named after professor V. N. Finkel

Omsk State Technical University, Omsk, Russia
O. A. Peregudov, Cand. Eng., Vice-Rector for Youth Policy and Educational Activities

Abstract: Using transmission electron diffraction microscopy, the formation of a defective pearlite substructure in the head of special-purpose rails of DT400IK category with increased wear resistance and contact endurance made of hypereutectoid E90KhAF steel was studied after operation (passed tonnage 187 million tons gross). At distances of 0, 2, 10 mm from the rolling surface along the central axis, four morphological components of pearlite were analyzed: lamellar, fragmented, destroyed and globular. The scalar and excess dislocation density, the sizes of cementite fragments and particles, internal stress fields and their non-monotonic change across the head cross section were determined. The transformation paths of lamellar pearlite were established, the destruction of which ensures fragmentation and formation of a subgrain structure, the redistribution of cementite particles in the morphological components and formation of elastic distortions of the steel matrix crystal lattice. A physical interpretation of the observed dependencies is presented.
We express our gratitude to E. V. Polevoy, Cand. Eng., for providing samples, I. Yu. Litovchenko, Dr. Phys.-Math., for assistance in conducting electron microscopic studies and R. E. Kryukov, Dr. Eng., for discussion of the results.

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