Flute end mill is a type of high-speed machining (HSM) tool material that is widely used. This type of material is produced by powder metallurgy. It consists of hard carbide (usually tungsten carbide WC) particles and a softer metal bond. composition. 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 alloys can also be added. element. Why are there so many cemented carbide grades? How does a cemented carbide tool manufacturer choose the right tool material for a particular cutting process? In order to answer these questions, let us first understand what makes flute end mill an ideal tool Various characteristics of materials.
(1) Hardness and toughness
WC-Co cemented carbide tools have 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 a hardness far exceeding that of high-speed steel, and at the same time it can 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 blades 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 flute end mill performance and specific processing largely depends on the initial milling process.
(2) Pulverizing technology of cemented carbide tools
Tungsten carbide powder is obtained by carburizing tungsten (W) powder. The characteristics of tungsten carbide powder (especially its particle size) mainly depend on the particle size of the raw tungsten powder and the temperature and time of carburizing. Chemical control is also crucial, and the carbon content must be kept constant (close to the theoretical ratio of 6.13% by weight). In order to control the powder particle size through subsequent processes, a small amount of vanadium and/or chromium can be added before the carburizing treatment. Different downstream process conditions and different final processing uses require specific combinations of tungsten carbide particle size, carbon content, vanadium content, and chromium content. Through changes in these combinations, a variety of different tungsten carbide powders can be produced.
When tungsten carbide powder and metal bond are mixed and milled to produce cemented carbide powder, various combinations can be used. The more commonly used cobalt content is generally 3%-25% (weight ratio). If it is necessary to enhance the corrosion resistance of the tool, then nickel and chromium must be added. In addition, the metal bond can be further improved by adding other alloy components. For example, adding ruthenium to WC-Co cemented carbide can significantly improve its toughness without reducing its hardness. Increasing the content of the binder can also increase the toughness of the cemented carbide, but it will reduce its hardness.
The company focuses on aerospace, military, medical, auto parts, wind power new energy and other high-quality milling blade tap drill manufacturers, products can be divided into: tungsten stainless steel, titanium alloy, tungsten steel, cemented carbide, end mills, Various types of carbide tools such as CNC milling cutters, twist drills, etc.
