Um estudo de caso sobre o aço inoxidável martensítico AISI 420 com teor de carbono de 0,15%

Abstract

Martensitic stainless steels are widely used because they present good combinations of corrosion resistance, high hardness and good mechanical resistance, besides low cost. However, the crystalline structure of these steels with carbon contents below 0.20% is still not completely defined in the literature. Through a study of case of the AISI 420 steel with 0.15% of carbon using X-ray diffraction techniques by polycrystals, it is possible to describe with details its crystalline structure. The refinement using the Rietveld method displayed a good fit with a gof value of 1.7, Rwp of 8.49%, and R_Bragg of 3.17. The c/a parameter ratio of 1.0088 reveals the tetragonal nature of the structure. The observed values for the occupancies of atomic sites (0 0 0) and (½ ½ ½) by Iron (Fe) and Chromium (Cr) atoms are consistent with the stoichiometry determined through X-ray fluorescence analysis. Furthermore, these results indicate that there is no apparent preference for specific occupancy sites. The detailed structure presented here, for the first time, serves as a foundation for future studies in the analysis of low-carbon steel.