Characterisation of high-grade alloy behaviour in severe erosion-corrosion conditions

A study has been made of the erosion-corrosion behaviour of two nominally corrosion resistant alloys (a superduplex stainless steel, UNS S32760 and Inconel 625 (UNS N00625) and water-resistant material Stellite 6 (UNS AMS5387), The experiments comprised exposure to an impinging jet of 3.5% sodium chloride solution at 100 m/s, 18 degrees C and 50 degrees C in the absence of entrained solids and also with 1000 parts per million sand particles at 25 m/s and 50 degrees C. It was found that the passive film on the corrosion resistant materials remains essentially intact under solids-free impingement but that these alloys exhibit active corrosion under liquid-solid impingement and that the direct and indirect effects of corrosion on the erosion-corrosion behaviour of such alloys can be extensive. The study also demonstrated that there is a potential for significant galvanic interactions between materials when under different erosion regimes. (C) 1999 Elsevier Science S.A. All rights reserved.