| 摘要 |
PURPOSE:To control the fluctuation of the position of a welding part and to irradiate the welding part with high precision with a laser beam by restraining the oscillation in the circumferential direction of an open tube. CONSTITUTION:The edge parts E, E on both sides of a metal band are curved to face oppositely to each other with a forming roll, further formed in a shape enclosed with plural arcs projecting outside or an elliptic shape by means of a final fin pass roll 5, and after preheating by a high frequency preheater 7 and melting by a laser beam, the edge parts are held in-between and abutted with a squeezing roll 9 which is provided with a bore of nearly an identical shape as the bore of the fin pass roll. |
