Method for rapid isostatic pressing

Claim 2

The process of isostatically pressing an article at a temperature above its bonding temperature comprising: a. inserting said article in a dry isostatic pressing vessel; b. substantially filling said vessel with a liquid without said liquid contacting said article; and c. filling the remainder of said vessel and raising the pressure of said liquid to a pressure above the critical pressure of said liquid to compact said article before said article cools to a temperature below its bonding temperature.

Claim 3

The process of claim 1 wherein approximately nine tenths of said vessel is filled before said liquid contacts said article.

Claim 4

The process of claim 1 wherein said vessel is rotating while being filled.

Claim 5

The process of claim 1 wherein the liquid stream filling said vessel is substantially tangentially directed with respect to the adjacent vessel wall.

Claim 6

The process of claim 1 which further comprises the step of interposing an annular ring between said article and the walls of said vessel whereby said liquid does not contact said article until the annulus between said ring and the wall of said vessel is filled.

Claim 7

The process of claim 5 which further includes the step of interposing a second annular ring between said article and said first annular ring wherein the temperature of said second annular ring is greater than the temperature of said article.

Claim 8

Method of compacting a porous body by isostatic pressing techniques comprising heating the body to a selected temperature, said temperature being sufficiently high for adequate bonding and compacting of said heated body but below the fusion temperature thereof, inserting said heated body into a dry pressure vessel, closing and sealing the pressure vessel, rapidly pumping a liquid pressurizing medium into said pressure vessel to fill the same while avoiding direct contact of said medium with said heated body until said pressure vessel is substantially completely filled with said medium, rapidly increasing the pressure within the vessel to a preselected level sufficient to compact said body by continuing to pump said pressurizing medium into the vessel until said preselected pressure has been reached, said preselected pressure being greater than the critical pressure of said medium, the rate of pressure increase in said last mentioned step being adequate to prevent the formation of vapor in said vessel as a result of contact of said medium with said body sufficient to lower substantially the temperature of said heated body prior to compaction of said body, decreasing the pressure and withdrawing said medium from said pressure vessel, and removing the body from the pressure vessel.

Claim 9

Method of compacting a porous body by isostatic pressing techniques comprising heating the body to a selected temperature, said temperature being sufficiently high for adequate bonding and compacting of said heated body but below the fusion temperature thereof, inserting said heated body into a dry pressure vessel, closing and sealing the pressure vessel, rapidly pumping a liquid pressurizing medium into said pressure vessel to fill the same while avoiding direct contact of said medium with said heated body until said pressure vessel is substantially completely filled with said medium, rapidly increasing the pressure within the vessel to a preselected level sufficient to compact said body by continuing to pump said pressurizing medium into the vessel until said preselected pressure has been reached, said preselected pressure being greater than the critical pressure of said medium, the rate of pressure increase in said last mentioned step being adequate to prevent the formation of vapor in said vessel as a result of contact of said medium with said body sufficient to lower substantially the temperature of said heated body prior to compaction of said body, decreasing the pressure and withdrawing said medium from said pressure vessel, and removing the body from the pressure vessel.

Claim 10

The method of claim 7 in which the pressure vessel is cold.

Claim 11

The method of claim 7 in which additional heat is supplied to said body following insertion thereof into said pressure vessel.

Claim 12

The method of claim 7 in which said liquid pressurizing medium is water.

Claim 13

The method of claim 10 in which the porous body is a metal powder, the selected compacting temperature is about 2,200°F. and the preselected pressure is about 29,000 psi.

Claim 14

The method of claim 11 in which the metal powder is an iron base powder.

Claim 15

The method of claim 11 in which the metal powder is a nickel base powder.

Claim 16

The method of claim 7 in which said body is separated from the internal surfaces of said pressure vessel by being inserted in a shielding container and in which a space is provided between said shielding container and said internal surfaces, said liquid pressurizing medium being pumped into said space to fill the same thereby to avoid direct contact between said medium and said heated body until said pressure vessel is substantially completely filled with said medium.

Claim 17

Method of compacting a porous body by isostatic pressing techniques comprising heating the body to a selected temperature, said temperature being sufficiently high for adequate bonding and compacting of said heated body but below the fusion temperature thereof, inserting said heated body into a dry pressure vessel, closing and sealing the pressure vessel, rapidly pumping a liquid pressurizing medium into said pressure vessel to fill the same while avoiding direct contact of said medium with said heated body until said pressure vessel is substantially completely filled with said medium, said body being separated from the internal surfaces of said pressure vessel by a space and said liquid pressurizing medium being pumped at high velocity into said space tangentially to said internal surfaces of said vessel to form a liquid vortex within said space while filling the same, rapidly increasing the pressure within the vessel to a preselected level sufficient to compact said body by continuing to pump said pressuring medium into the vessel until said preselected pressure has been reached, said preselected pressure being greater than the critical pressure of said medium, decreasing the pressure and withdrawing said medium from said pressure vessel, and removing the body from the pressure vessel.

Claim 18

Method of compacting a porous body by isostatic pressing techniques comprising heating the body to a selected temperature, said temperature being sufficiently high for adequate bonding and compacting of said heated body but below the fusion temperature thereof, inserting said heated body into a dry pressure vessel, closing and sealing the pressure vessel, rapidly pumping a liquid pressurizing medium into said pressure vessel to fill the same while avoiding direct contact of said medium with said heated body until said pressure vessel is substantially completely filled with said medium, said body being separated from the internal surfaces of said pressure vessel by a space and said liquid pressurizing medium being pumped at high velocity into said space tangentially to said internal surfaces of said vessel to form a liquid vortex within said space while filling the same, rapidly increasing the pressure within the vessel to a preselected level sufficient to compact said body by continuing to pump said pressuring medium into the vessel until said preselected pressure has been reached, said preselected pressure being greater than the critical pressure of said medium, decreasing the pressure and withdrawing said medium from said pressure vessel, and removing the body from the pressure vessel.

Claim 19

Method of compacting a porous body by isostatic pressing techniques comprising heating the body to a selected temperature, said temperature being sufficiently high for adequate bonding and compacting of said heated body but below the fusion temperature thereof, inserting said heated body into a dry pressure vessel, closing and sealing the pressure vessel, rapidly pumping a liquid pressurizing medium into said pressure vessel to fill the same while avoiding direct contact of said medium with said heated body until said pressure vessel is substantially completely filled with said medium, said body being separated from the internal surfaces of said pressure vessel by a space and said vessel being provided with an inlet arranged tangentially to the internal surfaces of said pressure vessel said liquid pressurizing medium being pumped into said space through said inlet at high velocity to form a liquid vortex within said space while filling said space, rapidly increasing the pressure within the vessel to a preselected level sufficient to compact said body by continuing to pump said pressurizing medium into the vessel until said preselected pressure has been reached, said preselected pressure being greater than the critical pressure of said medium, decreasing the pressure and withdrawing said medium from said pressure vessel, and removing the body from the pressure vessel.

Claim 20

Method of compacting a porous body by isostatic pressing techniques comprising heating the body to a selected temperature, said temperature being sufficiently high for adequate bonding and compacting of said heated body but below the fusion temperature thereof, inserting said heated body into a dry pressure vessel, closing and sealing the pressure vessel, rapidly pumping a liquid pressurizing medium into said pressure vessel to fill the same while avoiding direct contact of said medium with said heated body until said pressure vessel is substantially completely filled with said medium, said body being separated from the internal surfaces of said pressure vessel by a space and said vessel being provided with an inlet arranged tangentially to the internal surfaces of said pressure vessel said liquid pressurizing medium being pumped into said space through said inlet at high velocity to form a liquid vortex within said space while filling said space, rapidly increasing the pressure within the vessel to a preselected level sufficient to compact said body by continuing to pump said pressurizing medium into the vessel until said preselected pressure has been reached, said preselected pressure being greater than the critical pressure of said medium, decreasing the pressure and withdrawing said medium from said pressure vessel, and removing the body from the pressure vessel.

Claim 21

Method of compacting a porous body by isostatic pressing techniques comprising heating the body to a selected temperature, said temperature being sufficiently high for adequate bonding and compacting of said heated body but below the fusion temperature thereof, inserting said heated body into a dry pressure vessel, closing and sealing the pressure vessel, rapidly pumping a liquid pressurizing medium into said pressure vessel to fill the same while avoiding direct contact of said medium with said heated body until said pressure vessel is substantially completely filled with said medium, said body being separated from the internal surfaces of said pressure vessel by a space, said liquid pressurizing medium being pumped into said space to fill the same, and said pressure vessel being rapidly rotated during the filling of said space to cause centrifugal forces to be exerted on said medium during said filling, rapidly increasing the pressure within the vessel to a preselected level sufficient to compact said body by continuing to pump said pressurizing medium into the vessel until said preselected pressure has been reached, said preselected pressure being greater than the critical pressure of said medium, decreasing the pressure and withdrawing said medium from said pressure vessel, and removing the body from the pressure vessel.

Claim 22

Method of compacting a porous body by isostatic pressing techniques comprising heating the body to a selected temperature, said temperature being sufficiently high for adequate bonding and compacting of said heated body but below the fusion temperature thereof, inserting said heated body into a dry pressure vessel, closing and sealing the pressure vessel, rapidly pumping a liquid pressurizing medium into said pressure vessel to fill the same while avoiding direct contact of said medium with said heated body until said pressure vessel is substantially completely filled with said medium, said body being separated from the internal surfaces of said pressure vessel by a space, said liquid pressurizing medium being pumped into said space to fill the same, and said pressure vessel being rapidly rotated during the filling of said space to cause centrifugal forces to be exerted on said medium during said filling, rapidly increasing the pressure within the vessel to a preselected level sufficient to compact said body by continuing to pump said pressurizing medium into the vessel until said preselected pressure has been reached, said preselected pressure being greater than the critical pressure of said medium, decreasing the pressure and withdrawing said medium from said pressure vessel, and removing the body from the pressure vessel.