摘要 |
A tube, which is especially employed for making the main frame tube of a bicycle, is fabricated by means of a 6-4Ti alloy sheet being fed to the forming mold with a feed device, being cold-rolled with the stamping block, winding the circumferential side of the forming mold as a tube blank with a spiral clearance extending along the tube blank, and welding the tube blank at the spiral clearance as a seam of the finished tube. In this way, the fabricated tube has an advantage of providing a high strength to resist being deformed easily. |