The effect of Widmanstaten structure on H 2S and stress corrosion (SSC) cracking for 20# steel gas pipeline

As SSC (sulfide and stress corrosion) cracking happened to 20# steel pipe under the corrosion environment of H 2S-CO 2-H 2O, the chemical composition and microstructure, the tensile property, hardness, and susceptibility for SCC of the specimens were studied. Comparison was also made between the newly-made tube and the employed one under the same conditions. The main reason resulting in SCC was Widmanstaten structure, and normalizing could help relieve the bend pipe from both Widmanstaten structure and SSC.