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

Abstract 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 a wear-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°C and 50°C in the absence of entrained solids and also with 1000 parts per million sand particles at 25 m/s and 50°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.