WC-Co cemented carbide (tungsten-cobalt cemented carbide) material is a kind of cemented carbide, which has the characteristics of high hardness, good wear resistance and stable chemical properties. It is mainly used in the manufacture of metal processing tools, mining tools, Wear parts.
Traditional WC-Co cemented carbide materials have uniform internal and external structures and consistent mechanical properties. When the hardness of the material is high, the wear resistance is better, but at the same time, the strength and toughness of the material will be significantly lower. On the contrary, when the strength and toughness are good, the hardness of the material will decrease, and the wear resistance of the material will be reduced accordingly. It can be seen that for traditional WC-Co cemented carbide materials, hardness and toughness are difficult to balance.
So, how to solve the contradiction between the hardness and toughness of cemented carbide materials? The common way is to put hard "armor" on the cemented carbide material, that is, to coat the surface of the cemented carbide substrate with better strength and toughness with high hardness PVD and CVD coatings. Although this is an effective method, there is a physical bond between the coating and the cemented carbide base material, and it is inevitable that the coating will peel off under external load or thermal stress during use.
However, pain points are also breakthrough points for innovation. According to market research by 3D Science Valley, the additive manufacturing of cemented carbide materials - 3D printing process, in this process, the WC-Co cemented carbide layer and diamond layer in the cemented carbide-diamond composite are 3D printed by means of Implement layer-to-layer combination. This kind of bonding is carried out by chemical bonding. Compared with the traditional physical bonding, this bonding method is stronger, can avoid the peeling of the coating during use, and has better hardness.
The additive manufacturing process is electron beam melting (EBM) 3D printing technology based on powder bed fusion, and based on this process, the research on the components of WC-Co cemented carbide layer-diamond composite material and the process parameters of material additive manufacturing is carried out. .
Material research includes the mass content and particle size of Co in WC-Co cemented carbide, the particle size and purity of diamond material, and the mass ratio of the two materials. In terms of process parameters, Hunan Yishu Intelligent Manufacturing explored the 3D printing parameters of this composite material, such as the scan rate, current, and melting temperature of electron beam melting scanning.
Through the samples manufactured by the above process, it is possible to obtain cemented carbide with thermal conductivity of 500-550W/mK, friction coefficient of 0.3-0.5, thermal expansion coefficient of 0.9-1.18×10-6 and hardness of 4800-5000HV- The diamond composite material has good hardness and impact toughness of 300-320J, which can well avoid the peeling of the coating.
3D Science Valley
Review
EBM 3D printing technology provides a new possibility for the processing of carbide-like wear-resistant material parts, and the application of this technology can be extended to more types of cemented carbide materials.
According to the market observation of 3D Science Valley, the material company VBN has developed 5 kinds of cemented carbide materials suitable for EBM 3D printing. The hardness, chromium content or carbide content of these materials are different for different segments. For example, one of the materials that can be used to make machining tools has a very high content of fine, well-dispersed carbides and is suitable for making hobbing knives, forming knives, electric cutting knives and wear parts. VBN has demonstrated that this material and additive manufacturing process can produce machining tools with higher productivity.
