THE BEHAVIOUR OF HETEROPHASE INCLUSIONS “PHASES ARE BESIDE” UNDER STEEL PRESSURE FORMING

Abstract

Purpose. The technological ductility of steels is largely determined by the behavior of non-metallic inclusions at different deformation temperatures. The aim of the work was to study the shape change of heterophase inclusions of the “phases are beside” under different conditions of steel processing by pressure. Methods. Identification of inclusions of the “phases are beside” before and after deformation according to different modes was carried out by several methods: metallographic, petrographic, X-ray spectral analysis. Results. It has been established that the phase-mineralogical composition of the heterophase inclusions of the “phases are beside” determines the processes of their change under hot and cold deformation. The level of plasticity of the phases of inclusions determines the nature of their interaction between themselves and the steel matrix during their joint deformation. A different combination of phases in the inclusions of the “phases are beside” implies a different shape change of the inclusion as a whole during hot or cold rolling of steels. Scientific novelty. The shape-changing features of heterophase inclusions of the “phases are beside” during hot and cold deformation were established. The important role of interfacial friction processes was shown, which develops on sections of the inclusion-matrix boundaries (with different inclusion phases) and on the internal boundaries in inclusions whose phases have different plasticity. It was shown that the character of the shape change of the“phases are beside” inclusions is determined by the mutual influence of inclusions phases on their joint deformation. The possibility of transforming the inclusion of “phases are beside” in the process of hot and cold deformation when machining steel with a vice is shown. Practical significance. The obtained results of the study dedicated to features formation of heterophasic inclusions of the “phases are beside” can be used in the development of technologies for producing steels with the regulated content of heterophase non-metallic inclusions, including the type of “phases are beside”. These results contribute to solving important problems associated with improving the technological ductility of steels for various purposes, as well as preventing the formation of defects during the processing of steels by pressure.