Effects of LSP oh Fracture Morphologies of Stress Corrosion Cracking of X70 Pipeline Steel Welded Joints

摘要

The surfaces of X70 pipeline steel welded joints were processed with laser shock wave, its sensitivity of stress corrosion was investigated in NACE saturated H_2S solutions by slow strain rate testing (SSRT), and its fracture surface was observed with scanning electric microscope (SEM), and the effects of LSP on resistance H_2S stress corrosion cracking (SSCC) behavior of X70 pipeline steel welded joints were discussed. The results show that the SSRT fracture of X70 pipeline steel welded joints in primitive state is cleavage rupture, and its stress corrosion cracking is obvious, the sensitivity index of SSCC is high; the fractures of X70 pipeline steel welded joints by LSP (laser shock processing) are mainly ductile rupture, while the sensitivity of SSCC is reduced, and the stress corrosion cracking in its fracture is not obvious, the sensitivity of stress corrosion cracking for X70 pipeline steel welded joints is effectively reduced by LSP.