Estudo da influência da temperatura do eletrólito na resistência à corrosão das ligas UNS S41003 e ENDUR 300EM NACL 500PPM

Abstract

The ENDUR 300 alloy is newly developed and belongs to the group of low carbon stainless steels, which has a mostly martensitic microstructure. It is marketed mainly for application as a structural steel in order to replace some carbon steels currently used. ENDUR 300 was obtained from a thermomechanical treatment applied to the UNS S41003 alloy. The aim of this work was to study the influence of temperature on corrosion resistance, due to the scarcity of information in the literature, of the alloy ENDUR 300in comparison with the alloy UNS S41003. The work methodology was carried out in the following stages: Sample preparation; Conducting open circuit potential electrochemical tests, potentiodynamic polarization and electrochemical impedance spectroscopy; and Characterization of the surface of the alloys after the corrosion process by means of Scanning Electron Microscopy (SEM). The results obtained showed that there was no significant change in the corrosion resistance of the ENDUR 300 alloy, the thermomechanical treatment caused only microstructural changes and improvements in mechanical properties. The main type of corrosive process observed was localized corrosion, in both alloys, due to the presence of pitsafter polarization tests. The effect of the increase intemperature, in general, did not causea significant influence on the corrosion resistance of the alloy, but the ENDUR 300 showed a reduction of pitting potencial (Epite)and a reduction of the capacitive arc in the impedance, when subjected to higher temperatures.