| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of forming a ring rolling raw material to be formed as a high-quality thermostable alloy ring.SOLUTION: For forming the ring rolling raw material, a ring rolling mill is used which includes: a main roll and a mandrel roll that are arranged opposite to the radial outer circumferential surface of the ring rolling raw material and the radial inner circumferential surface of the same, respectively; and an upper axial roll and a lower axial roll that are arranged opposite to the height-direction upper surface of the ring rolling raw material and the height-direction lower surface of the same, each of the axial rolls having a flat conical surface and a recessed part in the axial-direction end part of the axial roll. The ring rolling raw material is rolling-formed into a thermostable alloy ring by reducing a radial-direction interval between the main roll and the mandrel roll while heating the thermostable alloy raw material preformed in a ring shape to the recrystallization temperature or more. A cross-sectional shape 110 of the ring rolling raw material is a substantially symmetrical shape with respect to the center line dividing the height direction of the ring rolling raw material into two parts, and is formed in such a tapered shape that a height is reduced toward at least one of the inner diameter side and the outer diameter side of the center line. The tapered part forms a free space allowing for deformation of the ring rolling raw material in forming using the ring rolling mill, consequently abnormal heating in ring rolling is prevented. |
