【摘要】 选用有限差分方法计算带钢冷却过程中的温度场和温降曲线.在试验得到TTT曲线的前提下,应用Scheil定律和经典Avrami方程推导CCT曲线.在此基础上耦合温度场和相变过程来模拟轧件横截面的铁素体分布;由组织性能关系模型模拟轧件横截面上的性能分布,如屈服强度和抗拉强度.采用超快冷工艺分段冷却方式在现场生产低成本高性能的DP钢,获得低屈强比的DP700,铁素体晶粒约5~6μm,力学性能满足要求.断面上的组织分布预测可用来调整冷却路线,降低生产成本的同时提高生产效率.更多还原

【Abstract】 The finite differential method was applied to calculating the temperature field and temperature curve of the cooling process of strip.Based on the experimental TTT curve,the CCT curve was deduced from Scheil’s rule and Avrami equation.Then the temperature field and the phase transformation process were coupled to predict the ferrite grain distribution on the cross section of the strip.With the microstructure-property models the mechanical property distribution on the cross section,e.g.yield/tension strength,was calculated.The UFC(ultra fast cooling) technology and stepped cooling mode were applied to producing DP(dual phase) steels with low cost and good quality on site.The produced DP steels showed the low yield ratio,the tensile strength of 700 MPa and the ferrite grain size of 5~6 μm.This design process,adapting the cooling route based on the simulation results of the microstructure distribution,can decrease the production cost and increase the production efficiency.更多还原