Tungsten powder mixed with carbon powder: the quality of WC powder depends on the uniformity of the mixing of tungsten powder with carbon black. If the material is mixed unevenly, the tungsten carbide powder will appear black core and layered.

 

In the process of cemented carbide production, tungsten powder and carbon black are mixed in the ball mill (ratio of grinding media to material is 1:1 and diameter of steel ball is 35~50mm). The whole process generally requires 2~4h, until the naked eye to observe the end of the phenomenon of no delamination.

 

Tungsten carbide powder ball-milling: ball-milling is carried out in a ball crusher. The ratio of grinding media to material is 1:1 and diameter of steel ball is 10~45mm. Ball-milling time is determined according to process requirements, usually 2h. To prevent the powder from flying, the screening shall be carried out under closed conditions. Fine particles of tungsten carbide pass 200 mesh sieves, medium particles of tungsten carbide through 250 mesh sieves, coarse particles of tungsten carbide through 60 mesh screens.

 

 

Reasonable speed in the ball-milling should be between the minimum speed and the critical speed. Critical speed is that the alloy ball is no longer separated from the inner wall of the grinding tube at this speed, and the centrifugal force of the alloy ball is greater than that of the radial component of gravity. When the ball mill is running, because of the different speed, it will cause the material to appear different state in the grinding barrel.

 

1, Low speed: the abrasive strength is low and the material does not rise in the grinding process. Some of the material will pile up at the bottom and cannot be fully ground.

2, High speed: grinding role is not enough, which like the mixing effect.

3, Reasonable speed: the material is fully contacted with the grinding ball along the spherical direction, and the grinding effect is good.

 

During the production process, the ball milling efficiency is the highest when the ball mill speed is between 60%-75%.

 

Processing Parameters of Ball-Milling:

Filling factor: the ratio of the volume of the ball mill barrel to the volume of the material and alloy ball, usually 0.45-0.5.

Ratio of grinding media to material: the quality ratio of grinding balls (usually cemented carbide balls used in cemented carbide production) to powder materials.

Solid-to-liquid ratio: the quality of the raw powder and the mass ratio of the liquid medium. There is no addition liquid in the process of WC powder breakage.