控轧控冷工艺参数对B微合金化中碳钢组织的影响

Effect of Controlling Rolling and Cooling Parameters on Structure of B Microalloyed Medium-Carbon Steel

通过Gleeble-1500热模拟机的热压缩实验,研究了在760～820℃变形、750～840℃初始冷却并控轧控冷的微合金中碳钢(%:0.32～0.38C、0.001～0.010B、≤0.05Als)组织演变。结果表明,铁素体平均晶粒度随变形温度的降低而减小,随初始冷却温度的升高而增大;随着变形温度的降低,铁素体百分含量增加,珠光体球化趋势更明显;790℃变形时,初始冷却温度840℃为最佳工艺条件,此时能获得最大铁素体含量64.5%,远高于同类型普通中碳钢的54%;在晶界处存在一定数量的BN颗粒,有利于改善B钢塑性变形性能。

Development of structure of microalloying medium-carbon steel （%：0.32～0.38C、0.001～0.010B、≤0.05Als） controlling rolling and cooling with deformation at 760 - 820 ℃ and initial cooling at 750 - 840 ℃ has been stud- ied by hot compression test by Gleeble-1500 thermal simulation machine. Results show that the average ferrite grain size decreases with decreasing deformation temperature and increases with increasing initial cooling temperature, and with decreasing deformation temperature the percentage of ferrite increases and the spheroidizing trend of pearlite is more obvious ; the optimum process parameters are deformation temperature- 790 ℃ and initial cooling temperature- 840 ℃ to get maximum ferrite volume percentage- 64.5% that is far more than that 54% in general medium-carbon steel. The definite BN particles at grain boundary are available to improve the plastic deformation of B steel.