Análise da influência do nível de redução a frio na microestrutura e propriedades mecânicas do vergalhão CA-60 produzido com aço ABNT 1010.

Abstract

In the context of continuous improvement in industrial production of CA-60 rebar, specifically related to adjusting the chemical composition, this study was conducted to analyze the influence of the level cold reduction on the microstructure and mechanical properties of CA-60, produced from steel ABNT 1010. In this investigation, rebars with diameters of 3.4 mm and 4.2 mm were used, and they were obtained through the cold rolling of a 5.5 mm wire rod. The samples were manufactured and made available by a semi-integrated mill in the state of Ceará. Tensile tests were conducted to determine the mechanical properties. Microstructural characterization was performed by measuring the average grain size in the cross-section using the Heyn’s linear interception method and the ImageJ software. Such image processor was also employed to estimate the average grain length in the longitudinal section. The dimensional results of the crystals were statistically analyzed using the Student’s t-test and the Minitab software, with a 99% confidence interval. It was observed that, in the cross-section, the increase in the degree of cold reduction led to decrease in grain size, which- combined with work hardening- resulted in increased mechanical strength and decreased ductility of the samples. Furthermore, greater grain elongation in the longitudinal section was noted due to the higher level of cold reduction.