Abstract

MESQUITA, T.J.; NOGUEIRA, R.P.  and  BASTOS, I.N.. Factorial design applied to corrosion of superduplex stainless steel. Lat. Am. appl. res. [online]. 2011, vol.41, n.4, pp.311-315. ISSN 0327-0793.

Steels employed in offshore oil and gas production are subject to a very corrosive environment. Especially the new oilfields located in pre-salt layers imply the contact of steels with high brine concentration, high temperature and presence of corrosive gas such as CO₂. Besides these facts, stainless steels have to present higher mechanical properties obtained from an optimized heat treatment. In order to take into account these factors and their synergisms, on the present paper, we have chosen a factorial experimental design to study the corrosion behavior of superduplex steel UNS S32750 by electrochemical tests. The results of open circuit potential, polarization curves and electrochemical impedance were analyzed with statistical methods considering a confidence level of 95%. The factors that significantly affect the corrosion potential are the carbon dioxide and heat treatment; the corrosion current is sensitive to carbon dioxide, and the resistance of polarization is strongly affected by the CO₂ content.

Keywords : Superduplex stainless steel; Polarization; Factorial design.

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