Tungsten carbide has been born for nearly one hundred years, of which the forming technology has developed rapidly with the development of science and technology. In addition to common molding methods such as die pressing, extrusion pressing, injection molding and isostatic pressing, many new formation technologies, such as warm compaction, high velocity compaction, explosion suppression and dynamic magnetic compaction have been developed.

 

1, Warm Compaction

Warm compaction is a new technology developed in the field of powder metallurgy in recent years. It uses special powder heating, powder conveying and mold heating system, heating the pre-alloyed powder and mould with special lubricants, and then pressing and sintering. Compared with the traditional technology, it has the characteristics of low pressing pressure, small demoulding force, high density and strength of billet, good surface finish and so on.

 

 

No matter for plastic powder or brittle powder, warm compaction technology effectively improves the density and strength of compact, which lays an experimental foundation for its application in the preparation of tungsten carbide. At present, the technology is mainly used in the production of other materials such as iron base and other materials, and some technology is applied to the production of tungsten carbide.

 

2, Warm Flow Compaction

On the basis of powder compaction and warm compaction technology, combined with the advantages of metal powder injection molding, a new technology of near net shape forming for powder metallurgy parts is put forward which is called warm flow compaction.

 

Its key technology is to improve the fluidity of the mixed powder. By improving the fluidity, filling ability and formability of the mixed powder, it can precisely form parts with complex geometric shape on the traditional press at 80-130℃. As early as 2000, foreign countries have started to research the application of the warm flow compaction technology in the tungsten carbide.

 

3, High Velocity Compaction

Under the pressing speed of 2~30m/s and the pressing pressure of 600~1000MPa, the powder is suppressed by a heavy hammer produced by a hydraulic hammer during high velocity compaction. Compared with the traditional mold pressing, the process is the same and the die is similar, but the pressing speed is 500~1000 times faster than the traditional pressing speed. It can make the material performance better, and its repeated repressing characteristics make the small and medium equipment have the ability to produce large size parts.

 

4, Dynamic Magnetic Compaction

Dynamic magnetic compaction is a new type of high performance powder final forming pressing technology, which began to be studied in the United States in 1995. The cost of maintenance and production is lower because of the nonuse of the mold. The pressure can be applied in any temperature and atmosphere, and it is more flexible for the working conditions of all materials. Without the use of lubricants and bonding agents, it is beneficial to environmental protection.