| 摘要 |
PURPOSE:To control lateral bending of a steel tube after expanding tube by adjusting restraining force that restrains the steel tube from both sides of side rollers arranged forward of the advancing direction of the steel tube from the expanding head of a mechanical expander. CONSTITUTION:Side rollers 1, 1 that restrain expanded steel tube X from both outsides are arranged forward of the advancing direction of the steel tube X from the expanding head A of a mechanical expander. Restraining force of these side rollers 1, 1 is calculated and adjusted by a formula P=M/l=sigma2.Z/l where M: bending moment, l: distance between the expanding head A and side roller 1, sigma2: stress in longitudinal direction, Z: section modulus. Thus, lateral bending caused at the time of expanding due to the circumferential variance of material strength of the steel tube X and the variance of plate thickness etc. is controlled. |
