| 摘要 |
PURPOSE:To improve the shape accuracy of a bend forming part by performing the bend forming of the inner both side parts of the bend forming part having a fixed curvature by preceding it in case of forming by bending a strip plate material in the cross sectional shape having the bend forming part of a fixed curvature, the bend forming part having different curvature at both side parts thereof or a linear part. CONSTITUTION:P5-P6 are subjected to a bend forming by preceding P6-P9 by bend- forming both side parts P5 and P6 only in the inner width direction of P5-P9 with the bending the bending radius of r1 in the angle range of a1 by tacking the symbol of P1-P9 on one part in the width direction of the strip plate S of the materials in case of bend-forming the hat shape steel in the cross sectional shape having the bend-forming part (a) with slightly larger radius r4 of curvature on the center part, linear part b, b at both sides thereof, further the leg bend-forming part, c, c with small radius of curvature and linear lug part d, d. The part of P7-P9 is bend-formed then by a radius 52 of curvature by coinciding the bending radius r2 of the inner both sides of P5-P9 with the bending radius r4 of the product. The P5-P8 is then taken in r3=r4 and P8-P9 taken in the radius t3 smaller than t2. The whole zone of the center bend-forming part (a) is finally formed with the r4 bending radius.
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