Method of particle ring-rolling for making metal rings

Claim 2

In a metal working system having means for ring-rolling an annular workpiece wherein the workpiece is rolled between a rotating mandrel and a drive roll having a larger diameter than that of the mandrel, the method of making a ring which comprises: a. forming a toroid-like encapsulating metal can having an annular cavity, b. filling the annular cavity with sinterable particles to make up a workpiece, and c. hot ring-rolling the workpiece to form a ring with a larger circumference than said workpiece of the desired configuration, size and microstructure.

Claim 3

The method as specified in claim 1 wherein the annular cavity of the can is closed and sealed.

Claim 4

The method as specified in claim 1 wherein the ratio of the internal diameter of the can to the wall thickness thereof ranges from a minimum of about 1 to 2 to the practical maximum.

Claim 5

The method as specified in claim 1 wherein the toroidal can comprises essentially two concentric cylinders radially spaced to form the annular cavity, and the ratio of the wall thickness of the inner cylinder to the wall thickness of the outer cylinder prior to ring-rolling, is substantially equal to the ratio of the overall outside diameter of the can to the inside diameter thereof, where the finally rolled wall thicknesses respectively, are to be substantially equal.

Claim 6

The method as specified in claim 1 wherein the sinterable particles are worked within a comparatively narrow temperature range and the heat conductivity of the metal can material does not exceed 0.06 calories/sq.cm./*C/second.

Claim 7

The method as specified in claim 1 wherein the coefficients of expansion of the outer metal wall of the toroidal can, the particle composition, and the inner metal wall of the can respectively, are in such descending order or magnitude that the resultant thermal stresses set up in the workpiece during and after ring-rolling are radially compressive.

Claim 8

The method as specified in claim 1 wherein the metal can at its opposite ends is closed by ring plates, and each plate is formed with an outwardly bowed convex surface with respect to the radius of the ring.

Claim 9

The method as specified in claim 1 wherein the metal can is composed of steel.

Claim 10

The method as specified in claim 1 wherein the particles are pre-alloyed.

Claim 11

The method as specified in claim 1 wherein the particles consist of a blend of different metals.

Claim 12

The method as specified in claim 1 wherein the particles comprise superalloy metal particles.

Claim 13

The method as specified in claim 1 wherein the particles within the can are densified prior to ring-rolling.

Claim 14

The method as specified in claim 1 wherein the particles are sintered within the can prior to ring-rolling.

Claim 15

The method as specified in claim 1 wherein the particles are hot densified within the can.

Claim 16

The method as specified in claim 1 wherein the particles are selected from the group consisting of aluminum and aluminum alloys.

Claim 17

The method as specified in claim 15 wherein the can is composed of aluminum.

Claim 18

The method as specified in claim 1 wherein the particles are selected from the group consisting of nickel and nickel alloys.

Claim 19

The method as specified in claim 17 wherein the can is composed of steel.

Claim 20

The method as specified in claim 11 wherein the encapsulating can is composed of the same material as the matrix of the particles.

Claim 21

The method as specified in claim 11 wherein the particles Are Inconel 718.

Claim 22

The method as specified in claim 11 wherein ring-rolling is started at a particle temperature above the solidus temperature thereof and is continued to a particle temperature well below the solidus temperature.

Claim 23

In a metal working system having means for ring-rolling an annular workpiece wherein the workpiece is rolled between a rotating mandrel and a drive roll having a larger diameter than that of the mandrel, the method of making a superalloy metal ring which comprises: a. forming a toroid-like metal can with an annular cavity, b. filling the cavity with metal particles having an overall superalloy composition, c. closing the can cavity to form a workpiece, d. hot ring-rolling the workpiece at a temperature above the solidus temperature, e. continuing ring-rolling until the particle mass is below the solidus temperature so as to form a ring with a larger circumference than said workpiece, and f. limiting the working temperature of ring-rolling to a comparatively narrow range above and below the solidus temperature.

Claim 24

In a metal working system having means for ring-rolling an annular workpiece wherein the workpiece is rolled between a rotating mandrel and a drive roll having a larger diameter than that of the mandrel, the method of making a superalloy metal ring which comprises: a. forming a toroid-like metal can with an annular cavity, b. filling the cavity with metal particles having an overall superalloy composition, c. closing the can cavity to form a workpiece, d. hot ring-rolling the workpiece at a temperature above the solidus temperature, e. continuing ring-rolling until the particle mass is below the solidus temperature so as to form a ring with a larger circumference than said workpiece, and f. limiting the working temperature of ring-rolling to a comparatively narrow range above and below the solidus temperature.

Claim 25

The method as specified in claim 22 wherein the metal particles comprise a blend of powder.

Claim 26

The method as specified in claim 22 wherein the metal particles are pre-alloyed.

Claim 27

The method as specified in claim 1, wherein the ratio of the mandrel diameter (D) to the thickness of the ring prior to a roll pass (to), is decreased for optimum working according to increased ductility and increased compaction of the sinterable particles worked.

Claim 28

The method according to claim 25 wherein the ratio D/to has minimum values of approximately 1 to 4 where the sinterable particles are of superalloy compositions.

Claim 29

The method according to claim 25 wherein the ratio D/to has minimum values of approximately 0.2 to 1.0 where the sinterable particles are irregular, uncompacted powders of ductile metals and alloys from a group including aluminum, nickel, copper and iron.

Claim 30

In a metal working system having means for ring-rolling an annular workpiece wherein the workpiece is rolled between a rotating mandrel and a drive roll having a larger diameter than that of the mandrel, the method of making a ring which comprises: a. forming a toroid-like metal can with an annular cavity; b. filling the cavity with a blended powder comprising a refractory metal carbide selected from the group consisting of titanium, tungsten and vanadium and a metal selected from the group consisting of iron, nickel and cobalt; and c. hot ring-rolling the workpiece to form a ring with a larger circumference than said workpiece of the desired configuration, size and microstructure.

Claim 31

In a metal working system having means for ring-rolling an annular workpiece wherein the workpiece is rolled between a rotating mandrel and a drive roll having a larger diameter than that of the mandrel, the method of making a ring which comprises: a. forming a toroid-like metal can with an annular cavity; b. filling the cavity with a blended powder comprising a refractory metal carbide selected from the group consisting of titanium, tungsten and vanadium and a metal selected from the group consisting of iron, nickel and cobalt; and c. hot ring-rolling the workpiece to form a ring with a larger circumference than said workpiece of the desired configuration, size and microstructure.

Claim 32

The method as specified in claim 28 wherein the workpiece is hot ring-rolled at a temperature above the solidus temperature of the blended powder.

Claim 33

The method as specified in claim 28 wherein the workpiece is hot ring-rolled at a temperature below the solidus temperature of the blended powder.

Claim 34

The method as specified in claim 28 wherein the blended powder is titanium carbide particles and a ferrous powder.