穿孔型双面电弧焊的传热与小孔形成

建立了穿孔型双面电弧焊小孔形态和传热的数学模型,考虑了作用于熔池上的各种力学因素,并采用帖体曲线坐标系处理复杂的熔池表面和小孔与熔池的边界。计算结果表明,熔透是穿孔的必要条件,熔透之后穿孔的速度远远大于熔透之前的。随着板厚的增加,熔透和穿孔所需的时间增加,并且熔透到穿孔的时间间隔也增大,但熔池的最小跨距变化不大,熔池的最小跨距可作为小孔建立的评价指标。小孔的形成使得焊接能量更加集中于电弧中心线附近,从而可以采用较小的焊接热输入,不开坡口一次焊透焊件。

NUMERICAL SIMULATION OF HEAT TRANSFER AND KEYHOLE FORMATIOM DURING KEYHOLE DOUBLE-SIDED ARC WELDING

All kinds of mechanics factors are considered synthetically. A mathematics model about keyhole conformation and heat transfer of double-side arc welding is established. The body-fitted coordinates are adopted in processing complex buddle surface and boundary between keyhole and buddle. The simulate results show that full penetration is prerequisite to perforation. The perforating speed after fully penetrating is far higher than that of before fully penetrating. The time need for fully penetrating, perforating and the span between full penetration and perforation increases with the thickness of plate increasing. The shortest span varies very small, thus the shortest span can be used as an evaluate object. The heat input are more concentrated around the centerline of the arc because of the keyhole, thus the workpiece free of groove can be fully penetrated using smaller heat input.