| 摘要 |
PURPOSE:To manufacture high quality square steel pipe continuously saving an equipment by suspending transportation of product made by bending a steel plate cut to specified length to the shape that approximates to a square steel pipe, tack welding the formed product, forming to the regular shape of a square steel pipe, high frequency welding the butted end and cutting off the tacked part. CONSTITUTION:Both side edges of a steel plate B pulled out from a material coil A and leveled 1 are trimmed by a trimmer 2, cut to a specified size, and formed by a press to the shape that approximates to a square steel pipe. The formed products C are put successively on a transportation passage 16. Transportation is suspended at the position of a tack welding machine 6, and the products C of upper side and lower side are tack welded to obtain a continuous formed product C. The product C is carried again and formed to the regular shape of a square steel pipe. At the same time, the left and right butted ends are high frequency welded 9, and the bead is removed 10. The continuous formed product C is cooled 11 and smoothed by a leveling roll 12. The tack welded part is cut off 14 utilizing suspension at the time of tack welding, and the square steel pipe having specified dimension is obtained. |
