| API X70MS 라인파이프용 강의 수소유기균열 감수성에 미치는 미세조직의 영향 |
| 성준호1,2, 심호섭1, 박병규1, 조경목2 |
1동국제강 중앙기술연구소
2부산대학교 재료공학부 |
| Effect of Microstructure on HIC Susceptibility of API X70MS Linepipe Steel |
| Joon-Ho Sung1,2, Ho-Seop Sim1, Byung-Gyu Park1, Kyung-Mox Cho2 |
1Dongkuk Steel R&D Center, Pohang 37874, Republic of Korea
2Department of Materials Science and Engineering, Pusan National University, Busan46241, Republic of Korea |
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Received: 24 January 2017; Accepted: 7 March 2017. Published online: 1 June 2017. |
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| ABSTRACT |
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The resistance of hydrogen induced cracking (HIC) was investigated with different microstructures of API X70MS steel. Ferrite/acicular ferrite (F/AF), deformed ferrite/acicular ferrite, ferrite/bainite (F/B) and single acicular ferrite (AF) were obtained by thermo-mechanical controlled process (TMCP) with changing rolling and cooling conditions. HIC resistance was found to be affected by the type as well as morphology of the microstructure, and thus the behavior of crack initiation and propagation could be analyzed. It was found that single AF and deformed F/AF with uniformly distributed dislocation reduced HIC initiation. Banded microstructure with a hardness value below 250 HV, such as AF, showed good HIC propagation resistance due to high toughness. AF generally exhibited excellent crack initiation and propagation resistance, namely the best HIC susceptibility performance. AF might redeem the HIC resistance for the banded microstructure also. |
| Keywords:
linepipe steel, microstructure, hydrogen induced cracking (HIC), acicular Ferrite, banded microstructure |
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