A method of producing a Ni-based superalloy is provided. A hot working material is used and consisting of a specific composition and has a solvus temperature of a phase of 1050 C. or more. The method includes: performing heating in a temperature of 980 C. to 1050 C. with an upper limit of 30 C. from the solvus temperature of the phase, for 10 hours or longer; and performing hot working on the material at a working speed of a strain rate of 2.0/second or more in the above temperature range.

A method of producing a Ni-based superalloy is provided. A hot working material is used and consisting of a specific composition and has a solvus temperature of a phase of 1050 C. or more. The method includes: performing heating in a temperature of 980 C. to 1050 C. with an upper limit of 30 C. from the solvus temperature of the phase, for 10 hours or longer; and performing hot working on the material at a working speed of a strain rate of 2.0/second or more in the above temperature range.

A ring-rolling mill (1) includes a machine table (2) for accommodating the rolled material (3) and an axial stand (4) that supports at least one axial roll, preferably two axial rolls (5, 6), for rolling the end faces (7, 8) of the rolled material (3). The ring-rolling mill and a method for operation thereof facilitate rapid product change without elaborate setting-up or without conversion of the rolling mill. For that purpose at least one pressure roll, preferably two pressure rolls (9, 10), for rolling the outer circumference (11) of the rolled material (3) is further arranged on the axial stand (4). The at least one pressure roll (9, 10) is arranged so as to be translationally displaceable relative to the axial stand (4).

A ring-rolling mill (1) includes a machine table (2) for accommodating the rolled material (3) and an axial stand (4) that supports at least one axial roll, preferably two axial rolls (5, 6), for rolling the end faces (7, 8) of the rolled material (3). The ring-rolling mill and a method for operation thereof facilitate rapid product change without elaborate setting-up or without conversion of the rolling mill. For that purpose at least one pressure roll, preferably two pressure rolls (9, 10), for rolling the outer circumference (11) of the rolled material (3) is further arranged on the axial stand (4). The at least one pressure roll (9, 10) is arranged so as to be translationally displaceable relative to the axial stand (4).

This invention relates to a combined ring rolling method for spherical valve body, which has the following procedures: 1) design for ring blank by computing ring blank volume and selecting reasonable rolling ratio according to the dimensions of forged ring; 2) design for rolling gap which includes the shapes and dimensions of working surfaces of main roll, mandrel and passive rolls according to the dimensions of ring blank and forged ring, the stable deformation condition of combined ring rolling and structure requirement of rolling equipment; 3) rolling forming with three stages of surface cross rolling, ring rolling and shaping by controlling of feeding speed of main roll and working positions of passive rolls. This invention has the technical economical advantages of low consumptions of energy and materials, high productivity and low production cost.

This invention relates to a combined ring rolling method for spherical valve body, which has the following procedures: 1) design for ring blank by computing ring blank volume and selecting reasonable rolling ratio according to the dimensions of forged ring; 2) design for rolling gap which includes the shapes and dimensions of working surfaces of main roll, mandrel and passive rolls according to the dimensions of ring blank and forged ring, the stable deformation condition of combined ring rolling and structure requirement of rolling equipment; 3) rolling forming with three stages of surface cross rolling, ring rolling and shaping by controlling of feeding speed of main roll and working positions of passive rolls. This invention has the technical economical advantages of low consumptions of energy and materials, high productivity and low production cost.

A ring rolling process and corresponding apparatus are disclosed. A ring shaped workpiece is provided, the ring shaped workpiece having a principal axis, an inner radial surface, an outer radial surface, a first axial surface and a second axial surface. The workpiece is subjected to radial pressure between a forming roll 150a acting on the outer radial surface and a mandrel roll 152a, 152b acting on the inner radial surface, at a radial roll bite region. A first axial roll 154a and a second axial roll 156a are provided at the first axial surface and the second axial surface respectively, to subject the workpiece to axial pressure. The first and second axial rolls 154a, 156a are provided at an angular position, measured around the workpiece and with respect to the principal axis, within 10 of said radial roll bite region. Multiple circumferential constraint rolls are provided around the outer radial surface or inner radial surface. In order to control the cross sectional shape of the workpiece, the mandrel roll 152a, 152b and/or the forming roll 150a has a projecting portion for contact with the workpiece, the projecting portion having an axial extent which is smaller than the axial height of the workpiece, the mandrel roll and/or forming roll being axially moveable relative to the workpiece.

A ring rolling process and corresponding apparatus are disclosed. A ring shaped workpiece is provided, the ring shaped workpiece having a principal axis, an inner radial surface, an outer radial surface, a first axial surface and a second axial surface. The workpiece is subjected to radial pressure between a forming roll 150a acting on the outer radial surface and a mandrel roll 152a, 152b acting on the inner radial surface, at a radial roll bite region. A first axial roll 154a and a second axial roll 156a are provided at the first axial surface and the second axial surface respectively, to subject the workpiece to axial pressure. The first and second axial rolls 154a, 156a are provided at an angular position, measured around the workpiece and with respect to the principal axis, within 10 of said radial roll bite region. Multiple circumferential constraint rolls are provided around the outer radial surface or inner radial surface. In order to control the cross sectional shape of the workpiece, the mandrel roll 152a, 152b and/or the forming roll 150a has a projecting portion for contact with the workpiece, the projecting portion having an axial extent which is smaller than the axial height of the workpiece, the mandrel roll and/or forming roll being axially moveable relative to the workpiece.

Provided is a ring-rolled member manufacturing method enabling stabilization of the attitude of the ring material without generating a defect and the like in the resulting ring-rolled member even when the main roll of the ring-rolling device is provided with the flange portions positioned on upper and lower sides of the ring material. A ring-rolling device used in the ring-rolled member manufacturing method of the present invention is provided with a main roll 10 and a mandrel roll 20. An outer peripheral face of the main roll includes a recessed portion 12 to accommodate the ring material and an outer peripheral face of the mandrel roll 20, an upper flange portion 11 positioned on an upper side thereof, and a lower flange portion 13 positioned on a lower side thereof. An inner face of the recessed portion includes a rolling face 12S to be in contact with an outer peripheral face of the ring material, an upper face on the upper flange portion side, and a lower face 13S on the lower flange portion side, the lower face 13S having a slope in such a way that an opening of the recessed portion 12 is enlarged. The slope starts from within a range of a distance corresponding to a thickness of the ring-rolled member from a line of intersection between the lower face 13S and the rolling face 12S. An angle of the slope is greater than 0.3 and no greater than 9 with reference to the perpendicular plane.

Provided is a ring-rolled member manufacturing method enabling stabilization of the attitude of the ring material without generating a defect and the like in the resulting ring-rolled member even when the main roll of the ring-rolling device is provided with the flange portions positioned on upper and lower sides of the ring material. A ring-rolling device used in the ring-rolled member manufacturing method of the present invention is provided with a main roll 10 and a mandrel roll 20. An outer peripheral face of the main roll includes a recessed portion 12 to accommodate the ring material and an outer peripheral face of the mandrel roll 20, an upper flange portion 11 positioned on an upper side thereof, and a lower flange portion 13 positioned on a lower side thereof. An inner face of the recessed portion includes a rolling face 12S to be in contact with an outer peripheral face of the ring material, an upper face on the upper flange portion side, and a lower face 13S on the lower flange portion side, the lower face 13S having a slope in such a way that an opening of the recessed portion 12 is enlarged. The slope starts from within a range of a distance corresponding to a thickness of the ring-rolled member from a line of intersection between the lower face 13S and the rolling face 12S. An angle of the slope is greater than 0.3 and no greater than 9 with reference to the perpendicular plane.