| 摘要 |
PROBLEM TO BE SOLVED: To propose a bending press molding method whereby a steel pipe of satisfactory quality can be obtained without increasing equipment cost, and to propose a manufacturing method for a steel pipe using the molding method.SOLUTION: A plate S is supported at two points by a die 2 arranged in the direction of feed of the plate S, and while the plate S is intermittently fed, a punch 5 is pressed against the plate between the supports of the die to apply three-point processing, thereby molding an open pipe. In this case, for the die 2 and punch 5, displacements at at least three points in the longitudinal direction thereof are measured. On the basis of the result of the measurement, the pressing force of the punch 5 is altered, and while exerting control such that the flexure of the punch 5 matches the flexure of the die 2, the three-point processing is performed. |
