Insight into the stress corrosion cracking of HP-13Cr stainless steel in the aggressive geothermal environment

•The effect of temperature and CO2 pressure on the stress corrosion cracking of HP-13Cr stainless steel was proposed.•The stress and strain concentration in pitting area was studied by finite element analysis.•A pitting-to-cracking model has been built to elucidating the initiation of stress corrosion cracking.•A “HTHP-SCC electrochemical system” was developed to conduct the electrochemistry measurement under applied stress. The stress corrosion cracking of HP-13Cr stainless steel in the geothermal environment was studied by experimental measurements and modeling calculations. The stress corrosion cracking susceptibility of HP-13Cr stainless steel increases with both temperature and CO2 pressure, and shows a synergistic effect greater than the temperature or CO2 pressure does singly. The fracture morphologies presented quasi-cleavage fracture characteristic in the geothermal environment. The stress corrosion cracking mechanism is dominated by the anodic process. The critical stress intensity factor for stress corrosion cracking was measured and the pitting-to-cracking process was clarified by a mechanism model.