Acta Metallurgica Sinica (English Letters) ›› 2012, Vol. 25 ›› Issue (2): 111-123.DOI: 10.11890/1006-7191-122-111

• 研究论文 • 上一篇    下一篇

Austenization temperature effects on the microstructure evolution of the medium manganese steel (0.2C-5Mn) during ART-annealing

徐海峰1,赵杰2,3,王昌4,王存宇4,时捷4,曹文全5,李箭2,董瀚3   

  1. 1. 华中科技大学
    2. 华中科技大学材料科学与工程学院
    3. 钢铁研究总院结构材料研究所
    4. 钢铁研究总院
    5.
  • 收稿日期:2011-08-22 修回日期:2011-12-12 出版日期:2012-04-25 发布日期:2012-04-11
  • 通讯作者: 徐海峰

Effect of austenization temperature on the microstructure evolution of the medium manganese steel (0.2C-5Mn) during ART-annealing

Jie SHI1, Haifeng XU1,2, Jie ZHAO1,2, Wenquan CAO1, Chang WANG1, Cunyu WANG1, Jian LI2,Han DONG1
   

  1. 1. National Engineering Research Center of Advanced Steel Technology, Central Iron and Steel Research Institute, Beijing 100081, China
    2. School of Materials Science and Engineering, State Key Laboratory of Material Processing and Die &  Mould Technology, Huazhong University of Science and Technology, Wuhan 430074, China
  • Received:2011-08-22 Revised:2011-12-12 Online:2012-04-25 Published:2012-04-11
  • Contact: HaifengXU

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摘要： Microstructure evolution during ART-annealing of 0.2C-5Mn steel processed by austenitation at different temperatures was examined by SEM, TEM and XRD. It was demonstrated that the initial microstructures resulted from austenization at different temperatures strongly affect the microstructure evolution during followed ART-annealing, even the ultrafine grained ferrite/austenite duplex structure with ~30% austenite could be obtained after long time ART-annealing in all cases. Austenization in the intercritical region (between Ac1 and Ac3) gave a duplex structure after quenching, which was nearly not affected by followed annealing process. However, high temperature austenization (above Ac3) resulted in a full martensite structure after quenching, which gradually transformed into a ferrite/austenite duplex structure during the following annealing process. Based on the analysis of austenite fraction and carbon concentrate, it was found that not only carbon partitioning but also manganese partitioning in the austenite affected the stability of austenite and even dominated the development of lamellar ferrite and austenite duplex structure during intercritical annealing with different time. At last an austenite lath nucleation and thickening model was proposed to describe the microstructure evolution of medium mangenese steel during ART-annealing.

Abstract: Microstructure evolution during ART-annealing (austenite reverted transformation annealing) of 0.2C-5Mn steel processed by austenitation at different temperatures was examined by SEM, TEM and XRD. It was demonstrated that the initial microstructures resulted from austenization at different temperatures strongly affect the microstructure evolution during followed ART-annealing, even the ultrafine grained ferrite/austenite duplex structure with about 30% austenite could be obtained after long time ART-annealing in all cases. Austenization in the intercritical region (between Ac1 and Ac3) gave a duplex structure after quenching, which was nearly not affected by followed annealing process. However, high temperature austenization (above Ac3) resulted in a full martensite structure after quenching, which gradually transformed into a ferrite/austenite duplex structure during the following annealing process. Based on the analysis of austenite fraction and carbon concentrate, it was found that not only carbon partitioning but also manganese partitioning in the austenite affected the stability of austenite and even dominated the development of lamellar ferrite and austenite duplex structure during intercritical annealing with different times. At last an austenite lath nucleation and thickening model was proposed to describe the microstructure evolution of medium mangenese steel during ART-annealing.

Key words: Austenization temperature, ART-annealing, Microstructure evolution, Carbon and manganese partitioning, Lamellar duplex structure