Effect of deformation thermocyclic treatment and normalizing on the mechanical properties of sheet Steel 10

Introduction. This paper investigates the influence of deformation thermocyclic treatment (DCT) and subsequent normalizing on the mechanical properties and microstructure of low-carbon Steel 10. Low-carbon steels are widely used in engineering due to its high ductility; however, traditional heat treatment methods have a limited effect on its strength. Steel 10, with slightly increased carbon content, is more susceptible to heat treatment, which allows for optimizing the balance between strength and ductility. The purpose of the work is to determine the optimal parameters of DCT and normalizing for achieving the best combination of mechanical properties of sheet steel Steel 10. In this work, Steel 10 samples, produced by OJSC “NKMC”, were studied. The methods of investigation include the analysis of the chemical composition using an emission spectrometer ARL 4460. Samples were subjected to cyclic forging (DCT) on a hydraulic press, followed by rolling to a thickness of 3 mm. Mechanical properties (tensile strength, yield strength, elongation, and reduction of area) were determined using a testing machine Instron 3369. Results and Discussion. The results showed that DCT leads to grain refinement and texture reduction, which improves ductility. The optimal normalizing temperature is 900°C, providing the best combination of strength and ductility for both conventionally treated and DCT-treated steel. At the same time, DCT slightly increases the strength but significantly increases the elongation (by 15 %) and the reduction of area (by 11%). Subsequent normalizing of the DCT-steel significantly increases ductility (by more than 50 %) and reduces strength. The data obtained allow for optimizing the technological process to achieve the desired balance of properties.