What are the basic knowledge of cemented carbide tool materials？
2023年 09月 02日
What are the basic knowledge of cemented carbide tool materials?
Cemented carbide is the most widely used high-speed machining (HSM) tool material. This type of material is produced by powder metallurgy and consists of hard carbide (usually tungsten carbide WC) particles and a softer metal bond Composition. At present, there are hundreds of WC-based cemented carbides with different compositions. Most of them use cobalt (Co) as a binder. Nickel (Ni) and chromium (Cr) are also commonly used binder elements, and other elements can also be added. Some TCGT Insert alloying elements. Why are there so many carbide grades? How does a tool manufacturer choose the right tool material for a particular cutting process? In order to answer these questions, let us first understand the various characteristics that make cemented carbide an ideal tool material.
Hardness and toughness:
WC-Co cemented carbide has unique advantages in both hardness and toughness. Tungsten carbide (WC) itself has a high hardness (more than corundum or alumina), and its hardness rarely decreases when the working temperature rises. However, it lacks sufficient toughness, which is an essential performance for cutting tools. In order to take advantage of the high hardness of tungsten carbide and improve its toughness, people use metal bonding agents to bond tungsten carbide together, so that this material has Threading Inserts a hardness far exceeding that of high-speed steel, while also being able to withstand most cutting processes. Cutting force. In addition, it can withstand the high cutting temperatures generated by high-speed machining.
Nowadays, almost all WC-Co tools and Inserts are coated, so the role of the base material seems to be less important. But in fact, it is the high elastic modulus of WC-Co material (a measure of stiffness, the room temperature elastic modulus of WC-Co is about three times that of high-speed steel) that provides a non-deformable substrate for the coating. The WC-Co matrix can also provide the required toughness. These properties are the basic characteristics of WC-Co materials, but it is also possible to customize the material properties by adjusting the material composition and microstructure when producing cemented carbide powder. Therefore, the suitability of tool performance and specific processing depends to a large extent on the initial milling process.
