Exploration of Cyclic Crack Resistance of Steel of Molten Load-Bearing Parts for Freight Cars

Purpose: Carrying out complex experimental studies of cyclic crack resistance of molten steel which is used for load-bearing parts of freight wagon running systems with kinetic diagram building for fatigue failure. Methods: Method of mechanical testing of molten steel samples under cyclic loading conditions was applied, the method makes it possible to obtain quantitative estimates of stuff ability to resist fatigue failure on the stage of fatigue crack development (testing on cyclic crack resistance). To study the surface of fatigue failure, relief micrographic analysis was used. To study molten steel elemental composition and the mechanisms of fatigue crack development, X-ray micro-spectral analysis was used on fatigue failure various stages. Results: The results of the research of cyclic crack resistance of 20 GL molten steel, which is used for load-bearing parts of freight cars, are presented. Fatigue failure kinetic diagram has been built, detailed micrographic analysis of fatigue failure surface has been carried out and elemental composition of non-metallic inclusions has been studied. Practical significance: Based on the research results, it is possible to assess the performance of 20 GL steel with cracks and to predict survivability. The results obtained make it possible to improve the methods of resource projection of molten bearing parts for freight wagon running systems in order to increase their operational reliability. The research results are used by enterprises - manufacturers of molten parts to control technology stability and to improve product quality.