Journal of the Korean Society for Heat Treatment (열처리공학회지)

The Korean Society for Heat Treatment (한국열처리공학회)
권호 표지

Effect of Initial Structure on the Retained Austenite and Tensile Properties of Fe-Si-Mn-P Steel Sheet

Fe-Si-Mn-P강판의 초기조직변화가 잔류오스테나이트 형성 및 인장성질에 미치는 영향

  • Moon, Won-Jin (Department of Metallurgical Engineering, Pukyong National University) ;
  • Kang, Chang-Yong (Department of Metallurgical Engineering, Pukyong National University) ;
  • Kim, Han-Goon (Department of Metallurgical Engineering, Pukyong National University) ;
  • Kim, Ki-Don (Technical research labolatories, Posco) ;
  • Sung, Jang-Hyun (Department of Metallurgical Engineering, Dong-A University)
  • 문원진 (부경대학교 공과대학 금속공학과) ;
  • 강창용 (부경대학교 공과대학 금속공학과) ;
  • 김한군 (부경대학교 공과대학 금속공학과) ;
  • 김기돈 (포항제철(주) 기술연구소) ;
  • 성장현 (동아대학교 공과대학 금속공학과)
  • Published : 1997.03.31
Download PDF
⟨ Previous Next ⟩

Abstract

This study has been conducted to investigate the effects of initial structure on the microstructure and tensile properties of high strength trip steel sheet. The initial structure before austempering remarkably influenced the second phase. The specimen with normalized initial structure showed mainly bainitic ferrite and retained austenite, while the as rolled specimen and spherodized specimen showed martensite plus retained austenite and martensite plus bainitic ferrite with small retained austenite, respectively. Two type of retained austenite, film type and granual type were observed in all specimens. The as rolled specimen appeared the highest contents of retained austenite owing to the compressive stress by cold rolling. The contents of retained austenite increased with increasing intercritical annealing temperature and austempering time. Tensile strength showed the highest in the as rolled specimen, while the highest elongation were obtained in the normalized specimen. The maximum T.S.${\times}$El. Value showed in normalized initial structure and increased with increasing intercritical annealing and austempering time. The highest Value of T.S.${\times}$El. obtained at austempering temperature of $400^{\circ}C$ and retained austenite of 12%.

Keywords