Cemented carbide is an alloy material made of hard compound of refractory metal and bonding metal through powder metallurgy process. It has the properties of high hardness, wear resistance, strength and toughness. Because of its unique properties, it is often used to make rock drilling tools, mining tools, drilling tools, measuring tools and so on. It is widely used in petroleum and natural gas, chemical industry, construction machinery, fluid control and other fields. Cemented carbide is a material pressed by powder metallurgy. Today, Chuangrui Xiaobian will introduce to you several major problems that we often encounter in the pressing process, and briefly analyze the reasons.
1. The more common pressing waste in the cemented carbide pressing process is delamination
Appearing along the edge of the pressure block, at a certain angle to the pressure surface, forming a neat interface is called delamination. Most of the layering starts at the corners and extends into the compact. The reason for the delamination of the compact is the elastic internal stress or elastic tension in the compact. For example, the cobalt content of the mixture is relatively low, the hardness of the carbide is high, the powder or particle is finer, the molding agent is too small or the distribution is not uniform, the mixture is too wet or too dry, the pressing pressure is too large, the unit weight is too large, and the pressing force is too high. The block shape is complex, the mold finish is too poor, and the table surface is uneven, which may cause delamination.
Therefore, improving the strength of the compact and reducing the internal stress and elastic back whistle of the compact is an effective method to solve the delamination.
2. The phenomenon of uncompressed (displayed particles) will also occur during the pressing process of cemented carbide.
Because the size of the pores of the compact is too large, it cannot completely disappear during the sintering process, resulting in more special pores remaining in the sintered body. The pellets are too hard, the pellets are too coarse, and the loose material is too large; the loose pellets are unevenly distributed in the cavity, and the unit weight is low. may cause uncompressed.
3. Another common pressing waste phenomenon in cemented carbide pressing is cracks
The phenomenon of irregular local fracture in the compact is called crack. Because the tensile stress inside the compact is greater than the tensile strength of the compact. The internal tensile stress of the compact comes from the elastic internal stress. Factors that affect delamination also affect cracking. The following measures can be taken to reduce the occurrence of cracks: prolong the holding time or pressurize multiple times, reduce the pressure, unit weight, improve the mold design and appropriately increase the thickness of the mold, speed up the demoulding speed, increase the molding agent, and increase the bulk density of the material.
The entire production process of cemented carbide is very critical. Zhuzhou Chuangrui Cemented Carbide Co., Ltd. has specialized in cemented carbide production for 18 years. If you have any questions about cemented carbide production, please pay attention to Chuangrui's official website.
Post time: May-31-2023