| 摘要 |
A formed beam having a different section area in a longitudinal direction is provided to reduce manufacturing costs for a beam by cutting a roll into plates. A formed beam having a different section area in a longitudinal direction comprises a web(120) and a flange. The central part of the web in a longitudinal direction is wider than the two end parts. The flange is integrated with the web. Two ends of the web have a first width, and the central part has a second width, which is larger than the first width. The flange includes upper and lower flanges(122,124). The formed beam having a different section area in a longitudinal direction is made by the following steps of: cutting a roll to make a plate along a cutting line; and bending the plate along a bending line. The cutting line includes first and second lines. The first line is drawn in a longitudinal direction of the roll. The second line is inclined with regard to the longitudinal direction of the roll. |
