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In this paper was analyzed the influence of annealing treatment on the microstructure and mechanical properties of ferrite-martensite of dual phase of high strength steel DP580. The analyzed microstructural transformations were the result of applying the annealing process in a temperature range of 150 to 500 ° C. Metallographic and fractographic analysis were performed on the initial steel and heat-treated steel by using optical and electron microscopy. Modifications in mechanical properties were evaluated by uniaxial tensile tests and by microhardness tests. It was observed that the used range of annealing temperatures affects gradually the microstructure, allowing obtaining different combinations of steel strength and ductility. The effects of annealing heat treatment on the dual phase steel analyzed are the result of a synergistic effect between the transformations in the martensite phase and ferrite phase. [ABSTRACT FROM AUTHOR]

In this work NbC coatings were deposited on AISI 316L steel substrates by reactive unbalanced magnetron sputtering. The coatings were deposited at room temperature to avoid heating alterations in the steel substrate microstructure, without bias and with a thickness of 200 nm. The coatings micro structure was characterized by X ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM). Adherence of the coatings was evaluated using the scratch test and its corrosion resistance was evaluated by potentiodynamic polarization and electrochemical impedance spectroscopy in a 3.5% NaCl solution. The results indicate that the coating NbC has (111) preferential orientation, exhibits good adhesion and has good corrosion resistance for stainless steels protection. [ABSTRACT FROM AUTHOR]