Elaboration of a new steel for high-strength railway wheels

Abstract

. Intensification of railway motion leads to toughening of requirements to both railway wheels design and quality of the material, used for their manufacturing. To provide the level of railway wheels strength not less that 1020 MPa and increased stability to defects formation on the surface of rolling, an elaboration of technological parameters of their heat strengthening was accomplished. Based on laboratory experiments and analytical studies results, recommendations presented on chemical composition of the new experimental steel for railway wheels. For industrial trial production of the railway wheels with hardness not less than 320 HB manufacturing, a steel micro-alloyed by vanadium decreased carbon content and increased silicon and manganese content was recommended. For the first time the regularities of phase transformations during continuous steel cooling was determined for railway wheels of trial chemical composition. Intervals of cooling rates were determined, within which variation of mechanism of structure formation at austenite disintegration observed. Using the finite-element method, the mathematical models of cooling rates calculation were elaborated in the ANSYS software package environment. The models were applied to calculate the cooling rates of the wheels rim while cooling at the vertical hardening machine. Results of the study of austenite disintegration kinetic were used to elaborate modes of thermal treatment of the experimental heat. Comparative studies of the railway wheels resistance against heat impact during braking were accomplished, as well as the work of the wheel rim stroke at negative temperature, the durability of wheels made of various steel grades. It was shown, that the trial steel has a high complex of service and operational properties comparing with steels, used for railway wheels of freight cars in the CIS countries.