高强度帘线钢LX82ACr的动态连续冷却转变行为

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

通过热模拟试验研究了LX82ACr帘线钢的动态连续冷却转变规律,采用OM对不同冷速冷却后的试样进行显微组织分析。研究了相变温度和过冷度随冷速的变化规律。对不同冷速冷却后的试样进行珠光体片层间距测量和硬度测量,并进行抗拉强度换算,研究了珠光体片层间距和抗拉强度随冷速的变化规律。结果表明,当冷速在3℃/s及以下时,转变后的组织为珠光体和索氏体;当冷速达到5℃/s时,组织中开始出现马氏体;随着冷速提高,马氏体含量逐渐增多,当冷速达到30℃/s及以上时,组织以马氏体为主。随着冷速提高,相变温度逐渐降低,过冷度逐渐增大,进行回归分析,拟合优度达到0.97以上。随着冷速提高,珠光体片层间距逐渐变细,抗拉强度逐渐提高,当冷速从0.1℃/s提高至9℃/s时,珠光体片层间距由0.1929μm减小至0.0739μm,抗拉强度由993.2 MPa提高至1388.4 MPa。分别对珠光体片层间距和抗拉强度进行回归分析,拟合优度均达到0.97以上。

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.