FORMATION OF DAMAGES IN BEARING STEELS IN AGGRESSIVE ENVIRONMENTS

Abstract. Purpose. The problem of influence of nonmetallic inclusions on the corrosion destruction of steels is actual. The goal of the work was to investigate the influence of the types of nonmetallic inclusions on their activity level in the origin of corrosion damage and the mechanical properties of bearing steels. Methods. Accelerated methods of corrosion testing of steels SHCH15 and SHCH15SG of specially obtained fusions, program contaminated with various types of nonmetallic inclusions, were used. Low fatigue tests were carried out in the air and in the various corrosive environments. An accelerated method was used to test the propensity of steels to stress corrosion cracking, as well as fatigue strength. Results. It was established that corrosion damages in bearing steels occur near nonmetallic inclusions of various types. The influence of non-metallic inclusions on the low-cycle fatigue and corrosive cracking in the air and in the various corrosive environments was shown. A sequential decreasing series has been established and justified, showing the degree of harmful influence of inclusions on the nucleation and development of corrosion damage in bearing steels. The most harmful effect of sulphides on the resistance of bearing steels in corrosive environments is substantiated. Scientific novelty. The peculiarities of the influence of various types of nonmetallic inclusions on the corrosion destruction of bearing steels have been established. A sequential decreasing series has been established and justified, showing the degree of harmful influence of inclusions on the nucleation and development of corrosion damage in bearing steels. Practical significance. The use of the obtained results allowed to develop technologies for electric melting of bearing steels with regulated content and types of nonmetallic inclusions, which will significantly increase their corrosion resistance.