Avaliação de rotas térmicas e termomecânicas para o estudo de tenacidade do aço AHSS DP800

Abstract

This work aims to evaluate the toughness of AHSS DP 800 steel through different thermomechanical rotations. Initially, the material was cut on a mechanical guillotine for the manufacture of test specimens and 4 thermomechanical sequences performing, where the first was performed with austenitization at 920 °C for 15 minutes for a reduction of 15%, the second for 20 minutes to a reduction of 10% in its cross section, ending with cooling in water at room temperature, performing a temper. And the third and fourth for 15 minutes for a 15% reduction, with temperature followed by a lead bath at 450°C and 480°C respectively. Tensile tests were also carried out to obtain data regarding the resistance limit, yield stress, deformation and toughness of the material as received and after the thermomechanical sequences. To conclude the experiments, a metallographic analysis of the microstructure of the material was carried out, cutting it, polishing it and applying a chemical attack for visualization in an optical microscope. The results found an increase in the resistance limit and yield stress of the AHSS DP 800 steel in routes 01 and 02 and a percentage reduction in deformation. As for toughness, the only route in which this property had an increase was 02. In routes 03 and 04, the same properties had a reduction in relation to the material as received. With the experiments carried out, the thermomechanical route 02, which was performed only with tempering, represented a great way to obtain an improvement in the tenacity of the AHSS DP800 steel, as well as in other properties, increasing the possibility of the material supporting muscles larger than that of flow.