Study on H₂S Corrosion Resistance of X100 SSAW Pipe

Conducted for the study purpose are the hydrogen induced cracking（HIC）test and the sulfide stress corrosion cracking（SSCC）test to the X100 spiral submerged arc welded（SSAW）pipe. The test results show that H₂S resistance of the pipe's weld joint is lower than that of the pipe body. And the analysis reveals the facts as follows. At the first，it is the banded structure and high hardness that act as the main role in causing excessive development of hydrogen induced cracking of both the welded joint and the pipe body，and the hydrogen induced cracks are mainly of transgranular fracture and intergranular fracture. And the SSCC occurring in the weld seam area is mainly due to the presence of inclusions in the weld seam proper，and the on-the-high-side and fluctuated hardness caused by the existence of the intergranular acicular ferrite structure in the weld seam and the granular bainite structure in the heat affected zone. Finally， the results from electrochemical polarization test and the residual stress test also further confirm that in case of the X100 SSAW pipe，its weld joint is more apt to be corroded than the pipe body proper.