11286 Near-Neutral pH SCC Properties of Pipeline Steels of Grade X80 and X52

Tuesday, March 15, 2011: 9:30 AM
Room 351 C (George R. Brown Convention Center)
Mitsuru Sawamura*1, Hitoshi Asahi1, Tomohiko Omura2, Hirofumi Kishikawa3, Nobuyuki Ishikawa4, and Mitsuo Kimura4
(1)Nippon Steel Corporation; (2)Sumitomo Metal Industries, Ltd. Corporate Research and Development Laboratories; (3)Sumitomo Metal Industries, Ltd. Pipe & Tube Company; (4)JFE Steel Corporation
Susceptibility to Stress Corrosion Cracking (SCC) of Grade X80 linepipe steels was investigated in near neutral pH conditions in comparison with conventional Grade X52 linepipes. X80 grade was manufactured by TMCP processes, whereas X52 grade was produced in controlled rolling (CR). SCC properties were evaluated by cyclic loading tensile tests in simulated solution (NS4 solution) that is typical environment for SCC under cathodic charging. Test results reveal that the Grade X80 and X52 had similar susceptibility to SCC, even the higher grade was tested under higher stress condition. It indicates that the Grade X80 have sufficient SCC resistance. This study was carried out in the High Strength Linepipe (HLP) Committee of the Iron and Steel Institute of Japan (ISIJ).