The use of powder extrusion technology to produce needle-shaped cemented carbide products and rods is a frequently used technology in cemented carbide production. Cemented carbide extrusion molding is a molding technology with great potential in modern cemented carbide production. However, cracks and other phenomena are also prone to occur in extruded products during the production process. Today, Sidi Xiaobian will share with you how to avoid cracks in cemented carbide extrusion molding.

Compared with traditional molding technology and isostatic pressing technology, the extrusion method has its uniqueness. The process flow of cemented carbide extrusion molding mainly includes the following processes: mixing powder and molding agent → extrusion molding → product pre-burning → vacuum sintering → finished product packaging → finished product. The production process looks very simple, but if the process parameters are not careful during the production process, cracked waste products are very likely to be produced.

There are many reasons for the generation of crack defects, such as unreasonable structural settings of the extrusion die, unsatisfactory molding agents, poor molding performance of the mixture, improper extrusion process, pre-burning process and sintering process, which are all important reasons for cracks in extruded products. We mainly analyze the influence of extrusion molding agents and pre-sintering heating rate.

The influence of extrusion molding agent on cracks:

Under the same extrusion conditions, using paraffin or Class A molding agent, adding too much or too little, the product will have different degrees of crack lines, and the crack rate of paraffin is higher than that of Class A. Therefore, in the production process of cemented carbide extrusion products, the selection of molding agent and the control of process parameters are extremely important factors.

The influence of pre-sintering heating rate:

The study shows that the cracks of semi-finished products are proportional to the heating rate. As the heating rate increases, the crack load increases. Using different pre-sintering heating rates for semi-finished products of different sizes is a good way to reduce product cracks.

In summary, if you want to reduce the crack phenomenon of cemented carbide extrusion products, you must pay attention to the following points: The production of cemented carbide extrusion products should strictly control the process and technical conditions. The use of Class A molding agent has high process stability and has a more obvious effect on preventing crack scrap. In addition, the pre-sintering heating rate of the extruded product is directly related to the occurrence of crack scrap. Small products use a faster heating rate, while large products use a slower heating rate. This is also an effective way to avoid cemented carbide extrusion crack scrap.