Main Characteristics of Cemented Carbide

Cemented carbide is an alloy material made of a hard compound of refractory metal and matrix metal through a powder metallurgy process. Because the ingredients contained in the powder metallurgy and the preparation method are different. The characteristics of cemented carbide are different. Let us discuss the main characteristics of cemented carbide in this article.

1. There is no directionality in cemented carbide. The cemented carbide is made of powder pressure sintering. Because the casting process is not used, there is no difference in density between the surface layer and the internal composition, thus eliminating the local mechanical function difference that may be caused by the density difference.

2. Cemented carbide does not have a heat treatment problem. The mechanical function of cemented carbide does not change by heating and cooling, it is only influenced by thermal stress during heating or cooling. Therefore, the pre-processing of the cemented carbide must be carried out before the sintering process. After sintering, it can only process with diamond tools. The mechanical function of cemented carbide is mainly determined by the amount of cobalt and the particle size of tungsten carbide. 

3. The Poisson's ratio of cemented carbide is 0.21~0.24. Therefore, cemented carbide mold’s inner diameter has a much smaller change than a steel mold under the action of processing stress. So, the size of cemented carbide product is very close to the size of the mold.

4. Carbide has high compressive strength. The cobalt content can determine the compressive strength. The compressive strength of cemented carbide products with low cobalt can reach more than 6000Mpa, which is nearly twice of steel.

5. Cemented carbide has a low coefficient of thermal expansion. People should consider this point in carbide mold design and manufacture.

6. High thermal conductivity. The thermal conductivity of cemented carbide is three times higher than stainless steel. 

7. The elastic deformation and plastic deformation of cemented carbide are small. 

8. Most popular characteristic of cemented carbide is its high hardness and high wear resistance. The usage time of tungsten carbide is longer than stainless steel.

At present, the cemented carbides used in domestic molds are mainly composed of tungsten and cobalt.