Stress corrosion cracking of X80 pipeline steel in simulated alkaline soil solution

The stress corrosion cracking susceptibility of X80 steel under applied cathodic potentials in a simulated soil solution was investigated using slow strain rate tensile tests. The fracture surfaces were observed by scanning electron microscopy. No apparent change of reduction in area was found at −775 mV in contrast to the open circuit potential. Many dimples were visible on both fracture surfaces. However, when the applied potentials were lower than −1000 mV, the SCC susceptibility increased as a result of evolution hydrogen, which diffuses into the steel. Pitts were found to be an important factor in the initiation of cracks.