| LI Qiong,LIU Zhi-yong,DU Cui-wei,LI Xiao-gang,LIU Ran-ke.Crack Propagation Behaviour of X80 Pipeline Steel in Near-neutral pH Solution under Different Applied Potential[J],44(3):31-35,51 |
| Crack Propagation Behaviour of X80 Pipeline Steel in Near-neutral pH Solution under Different Applied Potential |
| Received:November 12, 2014 Revised:March 20, 2015 |
| View Full Text View/Add Comment Download reader |
| DOI：10.16490/j.cnki.issn.1001-3660.2015.03.005 |
| KeyWord:X80 pipeline steel applied potential near-neutral pH crack propagation behavior |
| Author | Institution |
| LI Qiong |
Corrosion and Protection Center, University of Science and Technology Beijing, Beijng, China |
| LIU Zhi-yong |
Corrosion and Protection Center, University of Science and Technology Beijing, Beijng, China |
| DU Cui-wei |
Corrosion and Protection Center, University of Science and Technology Beijing, Beijng, China |
| LI Xiao-gang |
Corrosion and Protection Center, University of Science and Technology Beijing, Beijng, China |
| LIU Ran-ke |
Corrosion and Protection Center, University of Science and Technology Beijing, Beijng, China |
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| Abstract: |
| Objective To study the crack propagation behavior of X80 pipeline steel in near-neutral pH solution under different applied potential. Methods The cyclic loading experiment of X80 pipeline steel compact tension (CT) specimen under different applied potential was conducted and the crack length was recorded by a magnifying glass during the experiment. After the cyclic loading experiment, the micro-morphology of crack propagation surface was observed by Scanning electron microscope (SEM). The crack propagation rate of X80 pipeline steel in near-neutral pH solution under different applied potential and the crack propagation rule was analyzed. Results The brittle unstable fracture of CT specimen under open circuit condition occurred after 755 cycles and the crack propagation length was 4. 6 mm. The brittle unstable fracture of CT specimen under an applied potential of -775 mV (vs. SCE) occurred after 671 cycles and the crack propagation length was 3. 677 mm. The brittle unstable fracture of CT specimen under an applied potential of -1125 mV ( vs. SCE) occurred after 625 cycles and the crack propagation length was 3. 882 mm. Conclusion The crack propagation of X80 pipeline steel in near-neutral pH solution under open circuit condition and weak cathode potential was mix-controlled by anodic dissolution mechanism and hydrogen embrittlement mechanism, dominated by the anodic dissolution mechanism, and the crack propagation rate was low. With the decrease of the applied potential, the crack propogation mechanism was gradually dominated by the hydrogen embrittlement mechanism, and the crack propagation rate was obviously increased. |
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