SU1284689A1 - Apparatus for hot isostatic pressing with liquid - Google Patents

Abstract

The invention relates to powder metallurgy, in particular to devices for the isostatic hot pressing of a powder. The aim of the invention is to improve the performance of the device. The device comprises a high-pressure chamber, made in the form of a housing, a heater, and heat insulation. It is provided with bellows coaxially installed in each other. The bellows form three cavities: internal, intermediate and external. In the inner cavity there is a molded product in the melt environment, which is not oxidizing at the working temperature, in the intermediate cavity - a heater and heat insulation in the environment of the low-melting metal, and in the external one - liquid, whose boiling temperature is higher than the melting point of the low-melting metal. During pressing, pressure from the pressure source is transmitted through the fluid in the external cavity to the bellows, from the bellows to the liquid metal of the intermediate cavity, and from it through the internal bellows to the molten liquid and to the product. The device makes it possible to exclude operations for cooling down and draining the working medium, speeding up the time of pressure, and increasing productivity. 1 il. (L

Description

o

oo

05 00 (

The invention relates to powder metallurgy, in particular to equipment for hot isostatic pressing of powder and porous products and materials.

The purpose of the invention is to increase the performance of the device.

The drawing shows the device.

The device comprises a housing 1 provided with upper 2 and lower 3 plugs with hermetic seals forming a high-pressure chamber, heater 4, thermal insulation 5. On the upper plug, sylphons 6 and 7 are installed coaxially and hermetically, which divide the working space high pressure chambers on the inner 8, intermediate 9 and outer 10 cavities. A multiplier 11 is also integrated in the lower plug and there are channels for supplying the working medium to the external cavity 12.

The inner cavity is filled with molten salt or glass, provided with a lid 13 and is designed to stir, compress and preform, the intermediate cavity is filled with a low-melting metal, such as sodium, potassium, lead, or others, and is used for mixing, heating and insulating, and the outer cavity filled with mineral or synthetic oil, the boiling point of which is higher than the melting point of the metal, and connected to a pressure source.

The device works as follows.

The external cavity 10 is filled with oil, then the intermediate cavity 9 with liquid metal and the heater 4 is turned on, after which the temperature gradually increases, the working medium in the internal cavity 8 melts, which is pre-filled with a mixture of the appropriate type: salt or glass; at atmospheric pressure. Then raise the temperature to the working, increasing the power of the heater. In the melt load the workpiece or product, close the lid 13 and inject fluid into the external cavity 10, raising the pressure to a predetermined value. The bellows 7 transfers the pressure to the liquid metal in the intermediate cavity 9, and the bellows 6 through the melt in the cavity 8 - the working pressure on the product, carried out a hot isostatic pressing.

The melt, which has high thermal conductivities, ensures uniform temperature distribution over the product, thermal insulation 5 provides the necessary

lowering the temperature in the intermediate cavity 9, the oil layer provides additional heat insulation, since it has low values of the thermal conductivity coefficient.

There are no operations in the working cycle.

filling, heating, cooling and discharging the working medium, which makes it possible to significantly reduce the cycle time as compared with the known device. Using high-temperature tubular electric heaters 4 and a multiplier, raise the temperature to 1800-2000 ° C and pressure to 600 MPa. The device has increased reliability, since the sealing units operate at elevated temperatures in an oil medium, and the use of tubular electric heaters simplifies and makes the more reliable design of current leads. Finally, the device does not require special equipment for heating and pumping in each cycle of the liquid metal.

Thus, the device allows to increase productivity, because the number of operations in the cycle of hot isostatic pressing is reduced, and reliability is increased, since the sealing elements

operate under less severe conditions, improve performance, as the number of operations per cycle is reduced, and operating parameters can be increased to 2,000 ° C and 600 MPa. In addition, energy is saved in a cycle, since

There are no energy-intensive heating and cooling operations.

Claims (1)

Invention Formula Device for hot isostatic liquid compaction, including a high pressure chamber, made in the form of a housing with a heater and thermal insulation, in contrast to the fact that, in order to increase the productivity of the device, it is equipped with hermetic bellows, coaxially in one another installed in the chamber with the formation of an internal cavity, intermediate between bellows and the external cavity - between the external bellows and the wall of the high-pressure chamber, the internal the cavity is filled with a melt that is non-oxidizing at the working temperature in air, the intermediate cavity is filled with a low-melting metal, external liquid with a boiling point higher than the melting point of the low-melting metal, and the heater and heat insulation are placed in the intermediate cavity.