한국정밀공학회지 (Journal of the Korean Society for Precision Engineering)

  • 제21권2호
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  • Pages.168-176
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  • 2004
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  • 1225-9071(pISSN)
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  • 2287-8769(eISSN)
한국정밀공학회 (Korean Society for Precision Engineering)
권호 표지

개량 9Cr-1Mo 강의 장시간 크리프거동에 미치는 경도와 하부조직의 영향

Effect of Hardness and Substructure on Long-term Creep Behavior of Mod.9Cr-1Mo Steel

  • 박규섭 (요코하마국립대학 공학부 생산공학과) ;
  • 이근진 (양산대학 전자통신과) ;
  • 정한식 (국립경상대학 수송기계공학부) ;
  • 김정호 (한국광기술원 장비지원센터) ;
  • 정영관 (국립금오공과대학교 기계공학부) ;
  • 엔도타카오 (요코하마국립대학 공학부 생산공학과)
  • 발행 : 2004.02.01
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초록

Interrupted creep tests were carried out on the Mod.9Cr-1Mo steel in order to investigate the structural degradation during creep. The ranges of creep stress and temperature were from 71 to 167MPa and 873 to 923k, respectively. The change of hardness and tempered martensitic lath width were measured in the grip and gauge parts of interrupted specimens. The lath structure was thermally stable in static conditions, but was not stable during creep, and the structural evolution was enhanced by creep strain. The relation between the change in lath width and strain was described in the from, $\delta$W= a ($W_s-W_o$)$cdot;varepsilon$, where $\varepsilon$ is the strain, $W_o$is the initial lath width, $W_s$ is the final lath width depending solely on stress, and a is the constant of the magnitude of 0.67 $\mu$m /strain. The change in Victors hardness was expressed by a one-valued function of creep life consumption ratio. Based on the empirical relation between strain and lath width, a model was proposed to explain the relation between change in hardness and creep life consumption ratio. The model revealed that about 65$%$ of dislocations in lath structures were eliminated by the migration of subboundaries.

키워드

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