Isostatic Pressing Powder Molding

The principle of isostatic pressing is a molding method that utilizes the incompressibility of liquid medium and the uniform transmission of pressure, and is suitable for powder dense parts with equal pressure in all directions. With the advancement of science and technology, isostatic presses are more and more widely used in powder metallurgy, industrial ceramics, refractory materials, graphite carbon, magnetic materials and other industries. Compared with the conventional molding technology, the isostatic pressing molding technology has the advantages of uniform green compact density, high green body density, and small internal stress of the green body.

The isostatic press uses oil, water or gas as the working medium to apply the same ultra-high pressure on all surfaces of the object. It can make the molded workpiece have high and uniform density, uniform sintering shrinkage and easy machining.

The process of compacting powder into a green body with a certain shape, size, porosity and strength. Powder metallurgy is a process that uses the prepared metal powder, or a mixture of metal powder and non-metal powder as a raw material, through powder molding and sintering to manufacture metal materials, composite materials and various types of products. The powder metallurgy method is similar to the production of ceramics, so it is also called the cermet method.

Forming of metal powder materials is divided into two categories: press forming and special forming. It is a process of compacting metal powder into a compact with a certain shape, size, density and strength. It is one of the basic processes of powder metallurgy.

Before metal powder forming, powder pretreatment is generally required to meet the forming requirements. When mixing materials, a certain amount of powder forming additives must generally be added.

Powder compression molding is also called powder compression molding. Four-axis hydraulic presses are used to press compacts of various oil bearings, powder metallurgy anti-friction products, powder) Taiwan metal mechanical structural parts, etc. The design of the press and mold is continuously improved. Pressing parts with complex shapes has a higher degree of mechanization and automation.

The special forming of metal powder is used in occasions with special requirements on the shape, size and density of the billet. There are powder cold isostatic pressing forming, powder rolling forming, powder extrusion forming, powder slurry casting and powder explosion forming. Forming, etc., can produce high-precision, irregular-shaped products and thin-walled parts.

Isostatic pressing is a new forming method developed with the rise of modern powder metallurgy technology. Generally, isostatic pressing is divided into cold isostatic pressing and hot isostatic pressing according to its characteristics. The former often uses water or oil as the pressure medium, so It is called hydrostatic pressure, hydrostatic pressure or water-oil static pressure. The latter often uses gas (argon) as the pressure medium, which is called gas hot isostatic pressure.

It is easy to make high-performance integral jet turbine discs, hard alloy products with porosity close to zero, powdered high-speed steel ingots weighing up to 3 tons, etc. by hot isostatic pressing technology.

 The invention of isostatic pressing technology has a history of more than 60 years, but the development has been slow in the first 40 years. In the past 20 years, with the development of emerging technologies, powder metallurgy is required to provide more special-purpose materials and complex shapes. parts; so the rapid development of isostatic pressing technology occupies a very important position in the powder metallurgy forming process.