Abstract:
Due to the increasing demand and stricter tolerances by the automotive industry, there has been a significant increase of advanced high strength steels (AHSS) usage in vehicle construction. The continuous development of these materials results in more complex and refined microstructures, which ends up impacting the identification and quantification of their constituents. In this context, the microstructural evaluation of a multiphase steel produced by Usiminas was carried out using MTEX, a free Matlab toolbox. It was developed a methodology capable of performing the segmentation of similar lattice structures, such as martensite, ferrite and bainite, aiming at a more precise quantification of these constituents. The methodology was based on the evaluation of EBSD data, using the band slope component (BS) of the pattern quality. This analysis allows the visualization of microstructures in a very satisfactory way, since it is sensitive to the parameters of the crystal lattice and to the topology of the surface. Therefore, since different phases present different intensities of diffraction pattern, it is possible to generate contrast effects. Thus, the demarcation of the constituents took place through automatic adjustment calculations and the results were quite reliable to those observed visually. The method proved to be very effective in the analysis time improvement, in addition to overcoming other limitations related to the conventional methodology.