Verificación del diagrama esfuerzo-deformación de un acero AISI 1020 templado a temperaturas intercríticas usando la técnica RVE por elementos finitos.

Abstract

Currently, dual phase (DP) steels have been a determining factor at the industrial level, specifically in the manufacture of vehicle bodywork. According to the programme of vehicle steels for the future FSV it is expected that more than 30% of the production of bodywork for electric and hybrid vehicles will be made from DP steels. These steels are produced by thermomechanical processing and are composed of a soft ferrite matrix with a hard martensite phase. The mechanical properties of these materials depend on the properties of each phase (creep, hardness, etc.) and the volumetric fractions of these, within the microstructure. Due to their wide use, it is important to know more about the usefulness of these steels through modelling by finite elements. In this study a stress test according to the ASTM E-8 rule was carried out , inter-critical temperatures were calculated based on the chemical composition of the material; they were subsequently treated from temperatures of 750°C, 780°C and 810°C. From a metallographic study, the percentages of the phases in the specimens were obtained , the samples were subsequently characterized by microhardness testing, MOC and SEM. With the information collected, an analysis of the data was made, and based on a model of bilinear plasticity, a control volume (RVE) was constructed, it represented the microstructure of the material, using Solid Works the RVE was parameterized and modeled, by defining the volumetric distribution of the martensite in a matrix (ferrite), then it is simulated the mechanical behaviour of the RVE in ANSYS Workbench. The results obtained of stresses and deformations were compared with the data obtained experimentally, achieving approximations of up to 94% in the ultimate value of the stress.