Journal of the Korean Institute of Gas (한국가스학회지)

The Korean Institute of GAS (한국가스학회)
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Evaluation on Hydrogen Embrittlement of 5 Types of High Strength Dual Phase Steels by Small Punch Test

소형펀치시험에 의한 5종의 고강도 DP강 수소취성 평가

  • Choi, Jong-Un (Dept. of Materials Science & Engineering, Seoul National University of Science & Technology) ;
  • Han, Kyung-Gu (Dept. of Materials Science & Engineering, The Graduate School of Industry, Seoul National University of Science & Technology) ;
  • Park, Jae-Woo (Dept. of New Energy Engineering, The Graduate School of Energy & Environment, Seoul National University of Science & Technology) ;
  • Kang, Kae-Myung (Dept. of Materials Science & Engineering, Seoul National University of Science & Technology)
  • 최종운 (서울과학기술대학교 신소재공학과) ;
  • 한경구 (서울과학기술대학교 산업대학원 재료공학과) ;
  • 박재우 (서울과학기술대학교 에너지환경대학원 신에너지공학과) ;
  • 강계명 (서울과학기술대학교 신소재공학과)
  • Received : 2014.10.09
  • Accepted : 2014.10.28
  • Published : 2014.10.31
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Abstract

The hydrogen embrittlement degree of 5 type high strength DP steel charged with hydrogen by electrochemical method was evaluated by small punch test(SP test). After SP test, SP absorbed energy was remarkably decreased from 363 kgf-mm to 209 kgf-mm with increasing hydrogen charging time from 5hr to 50hr at DP5 specimen under the $200mA/cm^2$ current density condition. It was investigated that the decrease of hydrogen charging amount and SP absorbed energy according to the increase of current density and hydrogen charging time had a linear relationship. And it also investigated that the change of bulb height appeared by the SP test was decreased from 1.79mm to 1.59mm with the hydrogen charging conditions. It was supposed that it could be used as indicator of the evaluation of hydrogen embrittlement because of the similar trend of the formal results of SP absorbed energy. From the SEM observation of fracture area by crack in bulb, the morphology of fracture surface according to increasement of the hydrogen charging amount was varied with the cleavage mode.

전기화학적 방법으로 수소 주입시킨 5종의 고강도 DP강의 수소취성화 정도를 소형펀치시험으로 평가하였다. SP시험 후 SP흡수에너지는, $200mA/cm^2$ 전류밀도 조건의 DP5 시험편에서 수소주입시간이 5hr에서 50hr으로 증가함에 따라 363 kgf-mm에서 209 kgf-mm로 현저히 저하되는 것을 알 수 있었다. 전류밀도와 수소주입시간의 증가에 따라 수소주입량과 SP에너지 저하는 선형적인 상관관계를 갖는 것으로 조사되었다. 또한 SP시험에 의해 생성된 bulb의 높이 변화는 1.79 mm에서 1.59 mm로 낮아지는 것으로 조사되었다. 이는 앞서의 SP 흡수에너지 결과와 유사한 경향으로 나타나, 수소취성평가의 지표로 활용 가능할 것으로 사료된다. 균열 파단부위의 SEM 관찰에서 수소주입량 증가에 따라 파단면은 취성파면 형태로 진행되는 것을 확인할 수 있었다.

Keywords

References

  1. K. Hashigushi, T. Kato, M. Nishida, T. Tanaka, Kawasaki Steel Tech. Rep. 1, 70 (1980).
  2. H. Shirasawa, J.G. Thomson, Trans. ISIJ, 27, 360 (1987). https://doi.org/10.2355/isijinternational1966.27.360
  3. H.G. Nelson, D.P. Williams, A.S. Tetelman, Metall. Mater. Trans., 2B, 953 (1971).
  4. J. P. Hirth, Metall. Trans., 11A, 861 (1980).
  5. G. Katano, K. Ueyama, M. Mori, J. Mater. Sci., 36, 2277 (2001). https://doi.org/10.1023/A:1017568706014
  6. I. Moro, L. Briottet, P. Lemoine, E. Andrieu, C. Blanc, G. Odemer, Mater. Sci. Eng., 527A, 7252 (2010).
  7. M.P. Manahan, A.S. Argon, O.K. Harling, J. Nuclear Mater., 103, 1545 (1981).
  8. H.S. You, J.K. Lim, S.H. Chung, KWS, 12, 63 (1994)
  9. J.W. Park, K.M. Kang, Kor. J. Mater. Res., 22, 29 (2012). https://doi.org/10.3740/MRSK.2012.22.1.029
  10. J.U. Choi, J.W. Park, K.M. Kang, J. Kor. Inst. Surf. Eng., 46, 126 (2013). https://doi.org/10.5695/JKISE.2013.46.3.126
  11. J.W. Park, K.M. Kang, KIGAS, 18, 61 (2014).
  12. T. Zhang, W.Y. Chu, K.W. Gao, L.J. Qiao, Mater. Sci. Eng., 347A, 291 (2003).