Abstract: 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.

Key words: Double-sided arc welding, Full penetration, Heat transfer, Keyhole