Effect of Hydrogen Charging on Stress Corrosion Cracking of X80 Pipeline Steel in Simulated Yingtan Soil Solution

Stress corrosion cracking(SCC) of X80 pipeline steel after electrochemically hydrogencharging in an artificial solution simulated the waters contained in sour soil at Yingtan district in south China was studied by means of potentiodynamic polarization curves, slow strain rate tests(SSRT) and SEM observation. The results show that X80 pipeline steel has high SCC susceptibility in the solution after hydrogen-charging and the failure mode is transgranular cracking. Moreover,the SCC susceptibility and relative plasticity losses increased with increasing electrochemical charging time, the tensile fracture surfaces exhibited a change from ductile dimple fracture to cleavage fracture. In addition, permeation of hydrogen promoted the formation of pits,and therewith pits and nonmetallic inclusions in the steel were found to play an important role for the initiation of SCC cracks.