| 摘要 |
A method for manufacturing welded screw blanks includes obtaining circular blanks, cutting thereof along a radius, stretching into a spiral and welding the coils to each other. The circular blanks are made from a tape blank, which is bent and welded back to back to form a cylindrical shell. The butt joint is rolled between two rolls. Then stamping is carried out in two passages. While stamping at the first passage compressing and expanding such cylindrical shell are carried out simultaneously to form a conical shell. During the second passage compressing and expanding the conical shell are carried out to form a flat circular blank. |
