基于连续损伤力学模型的楔横轧心部疏松缺陷建模与应用研究

Research on modeling and application of core loose defects in cross wedge rolling based on continuous damage mechanics model

针对楔横轧心部疏松缺陷削弱材料强度,导致工件失效,影响零件的最终寿命的问题,采用一种基于连续损伤力学的耦合损伤模型研究了楔横轧心部疏松产生的规律。首先,通过拉伸实验、循环加载-卸载实验、缺口拉伸实验标定了调质45钢在26和500℃下的本构参数,再建立有限元模型进行仿真,研究了轧制温度、展宽角、断面收缩率和成形角对心部损伤演化的影响。结果表明,较低的轧制温度、较小的成形角、较大的展宽角和断面收缩率易使轧件心部产生疏松缺陷。在模具参数中展宽角、断面收缩率、成形角对心部损伤的影响依次减小。

Aiming at the problem that the core loose defects in cross wedge rolling weaken the strength of the material,lead to the failure of the workpiece,and affect the final life of the parts,a coupling damage model based on continuous damage mechanics was adopted to study the law of core loose generation in cross wedge rolling.Firstly,the constitutive parameters of quenched and tempered 45 steel at 26 and 500℃were calibrated by tensile experiments,cyclic loading-unloading experiments and notch tensile experiments,and then the finite element model for simulation was established to study the effects of rolling temperature,broadening angle,area reduction and forming angle on the core damage evolution.The results show that low rolling temperature,small forming angle,large broadening angle and area reduction are easy to cause core loose defects of rolled parts.Among the die parameters,the effects of broadening angle,area reduction and forming angle on core damage decreases in sequence.