대한금속재료학회지 (Korean Journal of Metals and Materials)

  • 제46권12호
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  • Pages.800-808
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  • 2008
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  • 1738-8228(pISSN)
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  • 2288-8241(eISSN)
대한금속재료학회 (The Korean Institute of Metals and Materials)
권호 표지

딜라토미터를 이용한 STD11 공구강의 오스테나이징 및 템퍼링 열처리에 따른 치수 변화 이방성 연구

Study on the Anisotropic Size Change by Austenitizing and Tempering Heat Treatment of STD11 Tool Steel Using Dilatometry

  • 홍기정 (포항산업과학연구원 신뢰성평가센터) ;
  • 강원국 (안동대학교 공과대학 신소재공학부) ;
  • 송진화 (포항산업과학연구원 신뢰성평가센터) ;
  • 정인상 (경북대학교 신소재공학부) ;
  • 이기안 (안동대학교 공과대학 신소재공학부)
  • Hong, Ki-Jung (Reliability Assessment Research Center, RIST) ;
  • Kang, Won-Guk (Andong National University, School of Advanced Materials Engineering) ;
  • Song, Jin-Hwa (Reliability Assessment Research Center, RIST) ;
  • Chung, In-Sang (School of Materials Science and Engineering, Kyungpook National University) ;
  • Lee, Kee-Ahn (Andong National University, School of Advanced Materials Engineering)
  • 투고 : 2008.09.22
  • 발행 : 2008.12.25
⟨ 이전 논문 다음 논문 ⟩

초록

Heat treatment is an important step for tool manufacture, but unavoidably generates dimensional distortion. This study investigated the continuous dimensional change and the anisotropic behavior of STD11 tool steel during austenitizing and tempering heat treatment especially using quenching dilatometer. Dilatometric results represented that the dimensional change along longitudinal direction was larger than that along transverse direction. Anisotropic phase transformation strain was produced in forged STD11 tool steel during heat treatment. Anisotropic dimensional change increased with increasing austenitizing temperature. After tempering, anisotropic distortion was partially reduced. FactSage thermodynamic equilibrium phase simulation and microstructural observation (FE-SEM, TEM) showed that large ($7{\sim}80{\mu}m$) elongated $M_7C_3$ carbides could be formed along rolling direction. The resolution of elongated carbides during austenitizing was found to be related with the change of martensite transformation temperature after heat treatment. Anisotropic size change of STD11 tool steel was mainly attributed to large elongated carbides produced during rolling process. Using dilatometric and metallographic examination, the possible mechanism of the anisotropic size change was also discussed.

키워드

과제정보

연구 과제 주관 기관 : 신기술연구조합

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