Effectiveness of Determination of Stress Corrosion Cracking Susceptibility of Pull-Out Plug by High Temperature Concentrated Alkali Solution Immersion Test

The stress corrosion cracking (SCC) sensitivity of 690 nickel base alloy mechanical pull-out plug (encapsulated plug sample) was tested by immersion test in high temperature concentrated alkali solution and observation of cross section morphology. The results showed that there were obvious intergranular stress corrosion cracks in the expansion transition zone of the plug, and its SCC sensitivity was significantly higher than that of other areas of the plug. This was because the localized plastic deformation in the expansion transition zone was discontinuous, resulting in higher localized residual stress. Under the joint action of high-temperature concentrated alkali solution, significant SCC appeared. The test results of multiple encapsulated plugs indicated that this method could effectively evaluate the SCC sensitivity of plug samples.