IMPROVEMENT OF THE MECHANICAL BEHAVIOR BY TAILORING OF NANOSTRUCTURED BAINITIC MICROSTRUCTURE BY TEMPERING AND PARTITIONING HEAT TREATMENT IN MEDIUM CARBON - SILICON COMMERCIAL STEEL
Technological advances suggest the development of new materials and new technologies that can provide economically competitive products with the desired mechanical properties. To improve the mechanical properties of commercial steel, a new quench and partition (Q&P) process was designed to provide a complex, nanostructured, multicomponent microstructure controlling the kinetics of carbon partition. In this project, the samples underwent two methods of full and intercritical austenitization, in one of them, the material was austenitized at 850°C for 3 minutes, and in the other method, the material was austenitized at 850°C for 3 minutes, followed by cooling to 805°C for 2 minutes to form proeutectoid ferrite grains. Quenching was performed at 220°C and partitioning at 325°C for 30 minutes and 375°C for 15 minutes, respectively, to determine bainite morphology from carbon partitioning from supersaturated martensite to retained austenite. The expansion curves were carefully analyzed to determine the phase transformations during the applied heat treatment. With X-ray diffraction (XRD), it was possible to identify the material's microstructures, quantify the austenite retained in the material, and estimate the dislocation density, microstrain, and crystallite size. For a more careful and detailed analysis of the microstructure, a scanning electron microscopy (SEM) analysis was carried out, which allowed the observation of the microstructures and morphologies resulting from the proposed heat treatments. Microhardness tests were carried out to verify the effect of the parameters used on the behavior of materials. Nanoindentation, EBSD, pin-disc, and tensile tests will be carried out in the next steps of this work to evaluate and verify the influence of nanostructured and complex multicomponent microstructure on the mechanical behavior and wear in commercial steel of medium carbon-silicon.