Forming method and forming device

Abstract

An object of the present invention is to provide a forming method and a forming machine in which in forming e.g., a round steel pipe, predetermined forming can be performed with less additional deformation imparted to a workpiece without deteriorating the productivity of the conventional roll forming, thereby manufacturing a high-quality product with high dimension precision. To achieve this object, the present invention provides a forming method and a forming machine, which adopt a rotating unit which rotatably moves on an endless track a die train having dies with outwardly directed and swingable forming passes in a breakdown step at an early forming stage, and in which the forming pass of each die holds the edge of the workpiece to rotatably move the die by changing the die to a predetermined angle, thereby realizing bending, so that problems due to twisting onto forming rolls and high locally-caused contact stress can be greatly reduced.