Influência da velocidade de deformação associada à temperatura em aço 1020

Abstract

Tension test on steels at room temperature are litte influenced by the speed at which are performed. With increase test temperature the influence of the strain rate is significant. Tests at elevated temperatures are important for the study of hot deformation of materials, normally under these conditions, the resistance decreases and the ductility increases, the plastic deformation is facilitated, thus reducing the stresses on the machines and parts to be fabricated by hot work. And the deformation speed also affects this behavior. This work aims to study the influence of strain rate associated with temperature in AISI 1020 steel. The basis of this study will be the tensile test, performed on test specimens of circular section, subjected to five different temperatures, applying three different strain rates. In this study, the strainstrain curves of engineering will be built, and obtained values of Yield Strength, Tensile Strength and Elongation. In the 15 tests performed, values of these properties were observed, which ranged from 60 to 650 MPa, of Resistance, and from 36 to 600 MPa, of Flow, resulting in a drastic reduction of the applied tension required for the deformation of the metal. The mechanical property of Ductility also experienced a variation, from 3 to 20% of Elongation. The measured curves will be compared with true strain-strain curves, calculated using the Ludwik-Hollomon equation. With these data, will be calculated the strain-hardening exponent (n), the coefficient of resistance (K) and the strain-rate sensitivity (m).