| 摘要 |
PURPOSE:To heighten density of an outer layer and improve a mechanical property by forging a composite roll outer layer of which is made of a hard alloy and an inner layer is made of a soft alloy by heating the outer layer to a proper temperature for forging and keeping the inner layer at a lower temperature. CONSTITUTION:A composite roll is formed by cold forming a powder metal (high speed steel) on the outer periphery of a round bar. Outer periphery is enclosed with ordinary steel to prevent deformation at the time of forging, and forged by heating. At this time, the forging machine is heated rapidly by induction heating. The outer layer is heated to the proper temperature for forging and the inner layer is maintained at the low temperature. By this way, the time of forging is shortened, and the deterioration of the mechanical property of the inner layer of the roll is improved remarkably. |
