Heat Treatment of Metals ›› 2023, Vol. 48 ›› Issue (6): 191-196.DOI: 10.13251/j.issn.0254-6051.2023.06.034

• Microstructure and Properties • Previous Articles     Next Articles

Continuous cooling transformation curves and microstructure of new-type slot edge steel

Xu Haifeng1,2,3, Li Hai1,3, Li Fengmin1,3, Fu Shengmin1,3, Ming Keyu1,3, Yu Yan1,3   

  1. 1. China Coal Zhangjiakou Coal Mining Machinery Co., Ltd., Zhangjiakou Hebei 075025, China;
    2. Institute for Special Steel, Central Iron and Steel Research Institute Company Limited, Beijing 100081, China;
    3. Hebei Province High-end Intelligent Mining Equipment Technology Innovation Center, Zhangjiakou Hebei 075025, China
  • Received:2022-12-16 Revised:2023-05-06 Published:2023-08-11

Abstract: Continuous cooling transformation behavior of a new-type slot edge steel was studied by thermal dilatometer, optical microscope and Vickers hardness tester, and the continuous cooling transformation (CCT) curves were obtained. The results show that the CCT curve diagram includes high temperature ferrite-pearlite transition zone, middle temperature bainite transition zone and low temperature martensite transition zone. When the cooling rate is less than 0.14 ℃/s, it is mainly the high temperature ferrite-pearlite transition zone. When the cooling rate is 0.14-0.81 ℃/s, the room temperature microstructure is mainly composed of ferrite, pearlite and bainite. When the cooling rate is 0.81-1.62 ℃/s, the room temperature microstructure is composed of ferrite, pearlite, bainite and martensite. When the cooling rate is 4.05 ℃/s, the high temperature transformation zone disappears, and the room temperature microstructure is bainite and martensite. When the cooling rate is higher than 8.10 ℃/s, it is a single-phase transformation zone of martensite. With the cooling rate increasing from 0.06 ℃/s to 40.5 ℃/s, the microstructure changes from ferrite+pearlite to bainite +martensite, and finally to single-phase martensite, and the room temperature microhardness increases from 195 HV5 (0.06 ℃/s) to 515 HV5 (40.5 ℃/s).

Key words: slot edge steel, continuous cooling transformation, microstructure, microhardness, CCT curves

CLC Number: