Heat Treatment of Metals ›› 2022, Vol. 47 ›› Issue (7): 92-97.DOI: 10.13251/j.issn.0254-6051.2022.07.016

• PROCESS RESEARCH • Previous Articles     Next Articles

Effect of reverse phase transformation annealing temperature after quenching on microstructure and properties of 5%Mn cold rolled medium manganese steel

Fan Lifeng1,2, Kang Ze1, Jia Liying3, Xu Huimin1, Gao Jun4   

  1. 1. School of Materials Science and Engineering, Inner Mongolia University of Technology, Hohhot Inner Mongolia 010051, China;
    2. Engineering Research Center of Rare Earth Metals, Inner Mongolia University of Technology, Hohhot Inner Mongolia 010051, China;
    3. Technology Center, HBIS GroupHansteel Company, Handan Hebei 056015, China;
    4. CSP Plant of Inner Mongolia Baotou Steel Union Co., Ltd., Baotou Inner Mongolia 014010, China
  • Received:2022-02-18 Revised:2022-05-24 Online:2022-07-25 Published:2022-08-12

Abstract: Effect of annealing temperature on microstructure and mechanical properties of a 5%Mn cold rolled medium manganese steel after quenching at 930 ℃ for 20 min and then reverse phase transformation annealing respectively at 660, 665, 675 and 685 ℃ for 30 min were studied by means of OM, SEM and XRD. The results show that after high temperature quenching and reverse phase transformation annealing, the microstructure of the 5%Mn cold rolled medium manganese steel is composed of ultra-fine-grained ferrite, lath martensite and austenite. As the reverse phase transformation annealing temperature increases from 660 ℃ to 685 ℃, the austenite content increases first then decreases and reaches the maximum value at 665 ℃, the tensile strength increases continuously, the yield strength increases first then decreases and reaches the maximum value at 675 ℃, and the elongation increases first then decreases and reaches the maximum value at 665 ℃. In conclusion, the comprehensive mechanical properties are the best for the 5%Mn cold rolled medium manganese steel after quenching at 930 ℃ for 20 min and then reverse phase transformation annealing at 665 ℃ for 30 min, at which the volume fraction of austenite is 24.24%, the tensile strength is 980 MPa, the elongation is 23.68%, and the product of strength and plasticity is 23.21 GPa·%.

Key words: cold-rolled medium manganese steel, annealing temperature, microstructure, mechanical properties

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