Continuous cooling transformation behavior of undercooled austenite of 700 MPa high strength weathering resistance steel

doi:10.13251/j.issn.0254-6051.2021.07.018

Abstract

Abstract: Continuous cooling phase transformation behavior of micro-alloyed weathering resistance steel with addition of Ni, Cr, Cu for carriage was studied by means of thermal simulation test machine, and the static and dynamic CCT curves of the tested steel were established. The results show that under the condition of no deformation, not all ferrite microstructure can be obtained at test cooling rates. When the cooling rate is 0.2 ℃/s, the ferrite content in the room temperature after cooling is the highest, which is 41%, and the average grain size is 36.9 μm. Under the condition of deformation of 30%, all ferrite and mintue quantity of pearlite microstructure can be obtained at the cooling rate of 0.2 ℃/s, and the average grain size is 17.9 μm, at which the tested steel has good corrosion resistance. When the cooling rate is in the range of 0.2-0.5 ℃/s (ferrite and pearlite phase transformation), the hardness of the tested steel increases with the rise of cooling rate. Under the condition of deformation of 30% and cooling rate of 0.2 ℃/s, the macrohardness of the tested steel reaches 181 HV30.

Key words: weathering resistance steel, ferrite, dynamic CCT curves, hardness

CLC Number:

TG142.23

Huo Jiansheng, Yan Dong. Continuous cooling transformation behavior of undercooled austenite of 700 MPa high strength weathering resistance steel[J]. Heat Treatment of Metals, 2021, 46(7): 94-97.

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