Defining the Limits of Application of Duplex Stainless Steel Coupled to Carbon Steel in Oilfield Environments

Abstract

Abstract Slow strain rate testing of solution-annealed (σ0.2 = 552 MPa [80 ksi]) and cold-worked (σ0.2 = 1,068 MPa [155 ksi]) 22%Cr duplex stainless steels (DSS) was conducted at different hydrogen charging currents in acid-brine solutions at 80°C (176°F). The charging currents and environments were designed to simulate coupling of DSS downhole tubulars to carbon steel casing, assuming a leak of production fluid into the annulus. In addition, a limited number of tests were conducted using less severe loading conditions, such as constant load and fluctuating load. To provide a framework for evaluating the results of the stress corrosion tests, hydrogen uptake was measured under equivalent conditions using primarily the electrochemical hydrogen permeation technique. Complementary tests were carried out using hot extraction techniques. In environments without hydrogen sulfide (H2S) at 80°C, there was no reduction in the plastic strain-to-failure of cold-worked DSS at charging currents typical of coupling to ...