RESEARCH OF STRUCTURE AND PROPERTIES OF LOW ALLOYED LOW CARBON STEEL WITH FERRITE-BAINITE STRUCTURE AFTER THERMAL HARDENING AND SUBSEQUENT TEMPERING

Keywords: stamped connecting parts of pipelines, heat treatment, microstructure, mechanical properties, fractography

Abstract

The purpose – to establish the laws of formation of a ferritic-bainitic structure in low-carbon low-alloy steels depending on the parameters of heat treatment. Determine the effect of heat treatment parameters on the properties of the connecting parts of pipelines made of these steels.
Methods. In the study of steel 15XCHD with a ferrite-bainitic structure after various heat treatment modes, the following methods were used: tensile testing of metal, impact bending of Charpy and Menage samples at different temperatures; light metallography; X-ray analysis of macro-, micro- and fine structure; fractographic analysis of failures using scanning electron microscopy.
Results. The regularities of the influence of heat treatment parameters on the structure, mechanical properties and topography of fractures of impact samples of 15XCHD steel with a ferrite-bainitic structure are established.
Originality. The research results made it possible for the first time to establish the dependence of the structure formation processes in low-carbon low-alloy steels on the parameters of the cooling medium, the method of thermal hardening, and the parameters of subsequent tempering. The influence of the heat treatment parameters on the change in the mechanical properties of the metal are established. Research results are protected by patents.
Practical implications. The obtained research results made it possible to create, test and implement the parameters of industrial technology for the volumetric heat treatment of stamped welded connecting parts of pipelines with wall thicknesses up to 100 mm and the structural and technological parameters of quenching equipment.

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Published
2020-03-30
How to Cite
Deineko, L., Borisenko, A., Taranenko, A., Zaytseva , T., & Romanova , N. (2020). RESEARCH OF STRUCTURE AND PROPERTIES OF LOW ALLOYED LOW CARBON STEEL WITH FERRITE-BAINITE STRUCTURE AFTER THERMAL HARDENING AND SUBSEQUENT TEMPERING. Metallurgical and Ore Mining Industry, (1), 33-46. https://doi.org/10.34185/0543-5749.2020-1-33-46