Journal of Materials Research and Technology (May 2023)

High pH-SCC mechanism investigation of novel Nb/Ce-additional X100 pipeline steel

  • Xiaojia Yang,
  • Qing Li,
  • Longfei Song,
  • Zhiyong Liu,
  • Xiaogang Li

Journal volume & issue
Vol. 24
pp. 488 – 502

Abstract

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High pH-SCC introduces great risks to the service safety of X100 pipeline steel. The design of new Nb and RE composite regulated pipeline steel can help to reduce the high pH-SCC. By the addition of Nb and Ce elements into traditional pipeline steel, the toughness of the pipeline steel was enhanced while the sensitivity of high pH-SCC decreased under the action of cathode potential. Mechanism research indicated that the increase of Nb element inhibited the cathodic hydrogen evolution reaction and increased the number of irreversible hydrogen traps in the steel, thus improving the resistance of pipeline steel to high pH-SCC. The addition of Ce element inhibited the anodic dissolution and cathodic hydrogen evolution processes, and reduced the high pH-SCC sensitivity of pipeline steel by changing the solution and precipitation of Nb.

Keywords