Effect of Electrochemical Potential and Chloride Concentration on Stress Corrosion Cracking Behavior of 23Co14Ni12Cr3Mo Ultra-High Strength Steel in NaCl Solution

摘要

The effect of electrochemical potential and chloride concentration on stress corrosion cracking (SCC)behavior of 23Co14Ni12Cr3Mo ultra-High strength steel were investigated by using slow strain ratetechnique (SSRT). Microstructure or morphology of fracture surfaces are characterized by using SEMat different applied potential conditions and NaCl concentrations. The SCC is attributed to the anodic- dissolution at the open circuit potential (OCP), which is affected with Cl ionsexistence. The SCCmechanism is anodic dissolution based, combined with hydrogen induced cracking. At appliedpotentials range from -550 to -395mVSCE, i.e. -500mVSCE, the 23Co14Ni12Cr3Mo steel is undercathodic protection, and the fracture morphologies are dimpled pattern dominated. Both positive andnegative potential shift increase the SCC susceptibility of 23Co14Ni12Cr3Mo steel.