Abstract: In order to improve the forming accuracy of square rectangular tube corners formed by roller forming, the causes of underfilling rectangular tube corners were analyzed according to the law of constant volume and the principle of equal metal flow per second. The finite element model of roll forming was established according to the actual production parameters in the factories, and the influences of pipe diameter and wall thickness on the thickening coefficient and corner filling degree in the forming processes were analyzed. According to the linear relation of arc length of neutral layer in underfilled regions of the corner, the tube diameter was corrected and the coefficient correction relation was determined. The damage of the corner forming processes was judged, and the appropriate diameter of the round pipe was selected. The simulation results were compared with the experimental ones. The results show that the corners are underfilled with the increase of wall thickness during roll forming. The decrease of wall thickness leads to the decrease of thickening coefficient, and the required diameters of circular pipes are smaller. With the increase of pipe diameters, the corner filling degree is better, at the same time, the increase of pipe diameters will increase the possibility of damage in the inner corner at the exit of roll forming. The errors between the test results and the experimental results are small, which verifies the accuracy of the simulation model. 

Key words: roll forming, corner filling degree, coefficient modification, corner damage

摘要： 为了提高矩形管辊弯成形角部的成形精度，根据体积不变定律和金属秒流量相等原则对矩形管角部欠充满原因进行分析；结合工厂实际生产参数建立辊弯成形有限元模型，分析圆管管径和壁厚对成形过程中增厚系数、角部充满度的影响；根据角部欠充满区域中性层弧长线性对应关系进行圆管管径修正，确定系数修正关系式；对角部成形过程进行损伤判定，筛选出合适的圆管管径，将其仿真结果与试验进行对比。结果表明：辊弯成形过程中壁厚的增大使得角部处于欠充满状态；壁厚越小，成形过程中的增厚系数越小，所需圆管管径越小；圆管管径越大，角部充满度越好，同时管径的增大会增加辊弯出口处角部内侧损伤的可能性；仿真与试验结果的误差较小，验证了仿真模型的准确性。

关键词: 辊弯成形, 角部充满度, 系数修正, 角部损伤