Testing and evaluation of mechanical properties of C45 steel with bainitic structure

Abstract

Purpose: The article aims to investigate the mechanical properties of C45 steel with a previously constituted bainitic structure, due to its widespread use in the machine industry. Design/methodology/approach: The input ferritic-pearlitic structure of steel was subjected to heat treatment in the form of quenching and tempering in order to obtain a bainitic structure. Tempering was carried out at different temperature and time values. It allowed various properties of the steel samples to be obtained, which were subsequently subjected to tensile strength and hardness testing. In addition, metallographic images of the resulting structures were taken. Findings: The results obtained from the tests were compiled in tabular form. Based on the results, correlations were observed in the tensile strength and hardness of the tested steel relative to various parameters of the hardening and tempering processes. Research limitations/implications: The strength properties testing of C45 steel with a bainitic structure was limited to determining the yield strength Re, tensile strength Rm, elongation A, and microhardness HV0.5. Practical implications: The tests confirmed the possibility of controlling heat treatment process parameters to achieve the desired mechanical properties of the steel. This may contribute to the practical control of the steel’s properties due to economic aspects and functional requirements. Originality/value: The article is primarily addressed to industrial practice, i.e., manufacturers of machine parts made of medium-carbon steel, due to the reduction in heat treatment time and energy consumption costs while maintaining the steel’s machinability and strength properties. © International OCSCO World Press. All rights reserved. 2024.