| 摘要 |
PROBLEM TO BE SOLVED: To eliminate shape defects in extruded shape such as bends which are generated on an extruded shape by primary and secondary straightening and also to obtain the extruded shape having the uniform proof strength and cross-section shape. SOLUTION: After the temperature of the extruded shape is lowered close to the room temperature right after extrusion, the extruded shape is primarily straightened at the constant amount of straightening, cut into such length as the extruded shape which is bent by its dead weight is not brought into contact with a table and, next, the extruded shape after cutting is secondarily straightened. In the secondary straightening, by fixing the amount of straightening, the proof strength and cross-sectional shape of the extruded shape are uniformized and, by adjusting the amount of straightening, a prescribed proof strength is imparted to the extruded shape. The extruded shape which is secondarily straightened is furthermore drawn as necessary. Consequently, because the proof strength and the cross-sectional shape are uniformized, the amount of springback generated when the extruded shape is bent does not vary and bent products excellent in the shape accuracy are obtained.
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