Heat Treatment of Metals ›› 2023, Vol. 48 ›› Issue (1): 127-132.DOI: 10.13251/j.issn.0254-6051.2023.01.022

• MATERIALS RESEARCH • Previous Articles     Next Articles

CCT curves and impact property of Q355D hot rolled H-steel

Wang Wenzheng1, Ma Yongfu2, Ma Jinhong1, Zhang Guiying2, Tian Yaqiang1, Cheng Xinchao2, Li Hongbin1, Chen Liansheng1   

  1. 1. Key Laboratory of the Ministry of Education for Modern Metallurgy Technology, North China University of Science and Technology, Tangshan Hebei 063210, China;
    2. Hebei Jinxi Iron and Steel Group Co., Ltd., Tangshan Hebei 064300, China
  • Received:2022-08-04 Revised:2022-10-26 Online:2023-01-25 Published:2023-02-03

Abstract: Continuous cooling transformation rule of Q355D hot-rolled H-steel was investigated on Glebble-3500 thermal simulation test machine by means of expansion method and metallography hardness method. In addition, static CCT curves were obtained. The results show that from the CCT curves, the microstructure of the steel is composed of ferrite and pearlite when the cooling rate is less than 1 ℃/s, ferrite, pearlite and bainite when the cooling rate is 1-10 ℃/s, and ferrite, bainite and martensite when the cooling rate is 20-50 ℃/s. With the increase of cooling rate, the hardness of the Q355D hot-rolled H-steel increases, and the hardness increases from 171 HV0.2 to 301 HV0.2. According to CCT curves, different rolling experiment schemes are worked out. When the total reduction is 75%, the strain rate is 0.3 s-1 and the deformation temperature is 1150 ℃, the ferrite grain size of the tested steel is 8.13 μm, and the impact absorbed energy at -20 ℃ is 146 J, with the best performance.

Key words: Q355D hot rolled H-steel, Nb-V microalloyed, microstructure, CCT curve, low temperature impact property

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