How to Avoid Cracks in Cemented Carbide Extrusion Products

It is common to use powder extrusion technology to produce tungsten carbide products and carbide rods in the production of tungsten carbide products. Cemented carbide extrusion is a potential forming technology in modern cemented carbide production. However, the extrusion products can still appear cracks during the production process. This article will talk about how to avoid cracks in cemented carbide extrusion molding.

The extrusion method has its uniqueness compared with traditional molding technology and isotactic pressing technology. The production process of cemented carbide extrusion molding includes the following steps: blending of powder and molding agent → extrusion molding → burning preparation → vacuum sintering → finished product packaging → finished product. The production process seems really easy, but it is very easy to produce cracked waste products if there are any negligent during the production.

There are many reasons for cracks, such as unreasonable structural settings of the extrusion die, unsatisfactory molding agent, poor molding performance of mixture, inappropriate extrusion process, pre-sintering process, and sintering process, etc.

The effect of extrusion molding agent on cracks:

If using paraffin or A-type molding agent under the same extrusion conditions, adding too much or not enough molding agent will both cause cracks on the products, Normally, the crack rate of paraffin wax is higher than that of A-type molding agent. Therefore, in the production process of cemented carbide extrusion products, the selection of the forming agent and the amount of control of molding agents are extremely important.

The effect of pre-sintering heating rate:

The crack of the semi-finished product is proportional related to the heating rate. With the acceleration of the heating rate, the crack increases. To reduce cracks on the product, the best way is to use different pre-sintering heating rates for different sizes of semi-finished products.

To sum up, in order to reduce the cracking phenomenon of cemented carbide extrusion products, it is important to be aware of the following points. The production process of cemented carbide extrusion products should be strictly controlled. The A-type forming agent has a better effect on preventing cracks in the products. In addition, the pre-sintering heating rate of extruded products is directly related to the occurrence of cracked waste products. Using a slower heating rate for large products and using a faster heating rate for small products are also effective ways to avoid cemented carbide extrusion crack waste.

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