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Information × Registration Number 0224U033054, (0123U102990) , R & D reports Title Research on the influence of chemical and structural heterogeneity of carbon steels on the reliability of large-sized rolled metal for railway purposes popup.stage_title Дослідження особливостей формування литого стану та якості сталі, що визначають кінцеву якість залізничних осей. Head Povorotnia Iryna R., Кандидат технічних наук Registration Date 17-12-2024 Organization Institute of Ferrous Metallurgy. ZI Nekrasov of the National Academy of Sciences of Ukraine popup.description1 Study of the influence of chemical and structural heterogeneity of carbon steels on the reliability of large-sized rolled metal for railway purposes Development of recommendations for improving the parameters of carbon steel manufacturing technology and the content of basic chemical elements to increase the reliability and durability of railway axles by managing chemical and structural homogeneity. popup.description2 Experimental ingots of carbon steels of different chemical compositions were melted. The samples were subjected to hot plastic deformation and heat treatment. Hot plastic deformation was carried out by the precipitation method at a temperature of 1260˚С by 50%. The subsequent heat treatment consisted of normalization from 850˚С. According to the results of metallographic research, the quantitative ratio of pearlite and ferrite in the experimental cast samples was calculated, after hot plastic deformation and after subsequent heat treatment. The hardness of the experimental steels in different states was determined by the Brinell method. The ideas about the formation of MnS sulfides and the influence of Mn concentration in relation to S during their formation were developed and it was established that at an S concentration of up to 0.025% and in the range of 0.58…0.63% Mn, the formation of MnS sulfides is 0.49% of the field of view of the test section at an estimated magnification of 100x, which corresponds to a score of 2 and 0.5 according to DSTU 31334 and EN 13261 at a level of 3.5 and 1.5 points, respectively. It was established that the number of pores, non-metallic inclusions and structural heterogeneity affect the fatigue strength and the number of cycles to failure. It was established that the reason for the 84.2% higher fatigue strength of sample No. 4 compared to sample No. 1, located in the surface layer of the axle, is primarily the 6.8 times smaller micropore size (51.9 μm versus 7.6 μm), as well as its higher hardness (by 10.5%) and less pronounced structural heterogeneity. The results of fatigue tests of the railway axle pl. No. 10745 of grade F (AAR M-101) produced by PJSC "INTERPIPE NTZ" (second batch of samples) showed that at a stress of 295-286 MPa, the surface layer of the product has a 28.2-160.7% higher level of fatigue strength than the inner layer at a depth of ½ the radius of the axle cross section. Product Description popup.authors Oliinyk Eduard V. Povorotnia Iryna R. Podolskyi Rostyslav V. Safronova Olena A. popup.nrat_date 2024-12-17 Close