Evaluation of Corrosion Resistance of Nickel-based Alloy EP718 for use in Hydrogen Sulphide Containing Environment

Abstract

Nickel-based alloys cover a wide range of oil and gas applications. Alloy EP718 is used as an analogue of alloy 718. The corrosion resistance of EP718 has been determined in severe environmental conditions of NACE level VI over 3 months (175°С, PCO2 = 3.5 MPa, PH2S = 3.5 MPa, pH 3.5, 20% NaCl). The effects of heat treatment on the corrosion rate were studied. The results indicate that the corrosion rate of EP718 in a simulated environment is less than 0.01 mm per year. Stress corrosion cracking could be observed in low quality production and incorrect heat treatment.