Method of making a metallic ring-shaped body

Abstract

A method for producing a hard metallic ring body is presented in which a stock material of a ring-shape is roll formed between a pair of inner and outer forming rolls, one of which is provided with a shape change section (shaping roll). Roll forming operations are performed in three fabrication stages; initial, intermediate and final fabrication stages. A gap between the inner and the outer rolls is maintained at all times during the three processing stages. Early in the initial fabrication stage, a depression region is formed in the stock material by engaging with the shape change section of the shaping roll, and this engagement is maintained throughout the fabrication stages. The shaping roll and the forming roll are designed so as to cause the stock material to flow in the axial direction by the radial compression forces between the shaping and forming rolls. Severe shape changes can thus be produced accurately and efficiently in the stock material by the cooperative action of the shaping roll and the forming roll. The formed body is mechanically processed and cold rolled as necessary to produce a completed ring body.