Journal of the Korean Society for Heat Treatment (열처리공학회지)

The Korean Society for Heat Treatment (한국열처리공학회)
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Influence of the Tempering Temperature on the Microstructure and Mechanical Properties of DP780 Dual-phase Steel

DP780 2상 조직강의 미세구조 및 기계적 특성에 미치는 템퍼링 온도의 영향

  • June Kang (Department of Materials Science and Engineering, Chosun University) ;
  • Chungseok Kim (Department of Materials Science and Engineering, Chosun University)
  • 강준이 (조선대학교 신소재공학과) ;
  • 김정석 (조선대학교 신소재공학과)
  • Received : 2024.10.16
  • Accepted : 2024.10.28
  • Published : 2024.11.30
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Abstract

This study investigated the hardness and microstructure of dual-phase (DP780) steel as a function of temperature and examined the effect of tempering temperature on the microstructure and mechanical properties of DP steel. The aim was to explore the changes in mechanical properties that rely on heat treatment when processing high-strength steel, widely used in the automotive industry. The dual-phase microstructure, composed of ferrite and martensite phases, showed variations in phase fractions with tempering temperature. Specifically, the hardness decreased up to 600℃, then increased above 600℃, with the lowest hardness observed at 600℃. This is attributed to the recovery and martensite decomposition caused by low-temperature tempering, leading to a decrease in hardness. Above 600℃, the formation of new martensite resulted in increased hardness. Therefore, high-strength steel with a dual-phase microstructure like DP780 is significantly affected by the martensite fraction resulting from tempering during processing, which has a substantial impact on its mechanical properties.

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Acknowledgement

본 과제(결과물)는 2024년도 교육부의 재원으로 한국연구재단의 지원을 받아 수행된 지자체-대학 협력기반 지역혁신 사업의 결과입니다(과제관리번호: 2021RIS-002).