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以L245级管线钢材料的热物性参数(密度、泊松比、杨氏模量、热膨胀系数、热导率和比热)和热模拟压缩实验获得的高温变形时应力—应变曲线等试验数据为基础,在MSC.Marc软件中建立了该钢种材料数据库,并建立了中厚板多道次轧制过程的二维有限元模型。以铸坯厚度为220mm、成品厚度为25.4mm的热轧过程为例,通过对轧件与轧辊接触面间换热系数采用取不同常数值的方法,并依据其生产时所采集的各道次相关工艺参数,对该轧件全道次热轧过程进行了数值模拟,将各道次的轧制力计算值与实测值进行了分析比较,确定了轧件与轧辊间接触面换热系数的最佳值。利用本文模型对厚度为180mm的轧件单道次轧制过程进行了数值模拟,研究了不同变形工艺参数(轧制温度、道次压下率和轧制速度)对变形区等效应变和等效应力的影响。结果表明,在轧机设备能力及生产现场条件允许时,高温粗轧阶段纵轧道次可采用低速大压下率进行轧制成形,使变形较充分地向轧件芯部渗透,从而使钢板获得细小均匀的晶粒组织,有效改善钢板的强韧性能。
The experimental data of thermomechanical parameters (density, Poisson’s ratio, Young’s modulus, thermal expansion coefficient, thermal conductivity and specific heat) of L245 grade pipeline steel and the stress-strain curve at high temperature deformation Based on the MSC.Marc software, the steel material database was established and a two-dimensional finite element model of multi-pass rolling process was established. Taking the hot rolling process with a slab thickness of 220 mm and a finished thickness of 25.4 mm as an example, different constant values are adopted by the heat transfer coefficient of the contact surface between the rolling element and the roll, and according to each pass The related process parameters were adopted to simulate the whole pass hot rolling process of the rolling process. The calculated and measured values of the rolling force of each pass were analyzed and compared. The heat transfer coefficient of the contact surface between the rolling part and the roll was determined best value. The single-pass rolling process with 180mm thickness was simulated by this model. The equivalent strain and deformation of deformation zone under different deformation parameters (rolling temperature, pass reduction rate and rolling speed) were studied. Effect of effective stress. The results show that when the capacity of the mill and the production site conditions are allowed, the high-temperature rough rolling stage longitudinal rolling pass can be rolled and formed by the low-speed and large reduction rate so that the deformation fully penetrates the rolling core and the steel plate is obtained Fine uniform grain structure, effectively improve the toughness of steel.