Avaliação da resistência à corrosão localizada de cladding de aço inoxidável duplex uns S39209 em aço carbono por meio de espectroscopia de impedância eletroquímica

Abstract

In this work electrochemical impedance spectroscopy tests were performed on the open circuit potential in samples of duplex steel UNS S39209 deposited by TIG welding on ASTM A36 steel sheets. A solution of 33% H2SO4+ 0.5% HCL with perturbations in the order of ± 10mV was used varying the frequency of 100Khz to 10mhz and 10 points per decade varying in potential. In order to evaluate the corrosion resistance of the duplex steel, relate to the ferrite / austenite volumetric fraction and compare with the results found by the DL-EPR technique.To reach the results an area adjustment was performed using the ferrite / austenite volumetric fraction. It was verified that the sample with lower dilution and austenite fraction presented higher resistance to corrosion than the others, consistent with the sensitization data. A tendency was observed for increasing the dilution and penetration of the addition metal with increasing welding energy. Deposition welding has proved to be an efficient option to increase the corrosion resistance of a material