Phase transformation behavior of high strength cord steel LX82ACr during dynamic continuous cooling

doi:10.13251/j.issn.0254-6051.2023.09.036

Abstract

Abstract: Characteristics of LX82ACr cord steel during dynamic continuous cooling were studied by thermal simulation, and the microstructures at different cooling rates were analyzed by using optical microscope. The pearlite lamellar spacing and hardness were measured at different cooling rates, and the tensile strength was converted from the hardness. The variation characteristics of phase transformation temperature, undercooling degree, pearlite lamellar spacing, and tensile strength with cooling rate were studied, respectively. The results show that when the cooling rate is 3 ℃/s and below, the microstructure is pearlite and sorbite. When the cooling rate reaches 5 ℃/s, the martensite begins to appear and its quantity increases with the increase of cooling rate. When the cooling rate reaches 30 ℃/s and above, the microstructure is mainly martensite. The phase transformation temperature decreases and the undercooling degree increases with the increase of cooling rate, and the regression analyses show that the goodness of each fitting reaches above 0.97. The pearlite lamellar spacing decreases and the tensile strength increases with the increase of cooling rate, and the regression analyses show that the goodness of each fit is also above 0.97. When the cooling rate increases from 0.1 ℃/s to 9 ℃/s, the pearlite lamellar spacing decreases from 0.1929 μm to 0.0739 μm, and the tensile strength increases from 993.2 MPa to 1388.4 MPa.

Key words: cord steel, dynamic continuous cooling, phase transformation temperature, pearlite lamellar spacing, tensile strength

CLC Number:

TG156.6

Li Zhanwei, Shen Kui, Ma Han, Zhang Yu. Phase transformation behavior of high strength cord steel LX82ACr during dynamic continuous cooling[J]. Heat Treatment of Metals, 2023, 48(9): 214-219.

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