⑴ Types of carbide cutting toolsAccording to the main chemical composition, cemented carbide can be divided into tungsten carbide-based cemented carbide and titanium carbon (nitride) (TiC(N))-based cemented carbide.Tungsten carbide-based cemented carbide includes three types: tungsten cobalt (YG), tungsten cobalt titanium (YT), and rare carbide added (YW). Each has its own advantages and disadvantages. The main components are tungsten carbide (WC) and titanium carbide. (TiC), tantalum carbide (TaC), niobium carbide (NbC), etc. The commonly used metal bonding phase is Co.Titanium carbon (nitride)-based cemented carbide is a cemented carbide with TiC as the main component (some add other carbides or nitrides). The commonly used metal bonding phases are Mo and Ni.ISO (International Organization for Standardization) divides cutting carbide into three categories:Category K, including Kl0~K40, is equivalent to my country’s YG category (the main component is WC.Co).P category, including P01 ~ P50, is equivalent to my country's YT category (the main component is WC.TiC.Co).M category, including M10~M40, is equivalent to my country's YW category (main component is WC-TiC-TaC(NbC)-Co).Each grade represents a series of alloys ranging from high hardness to maximum toughness with a number between 01 and 50.⑵ Performance characteristics of carbide cutting toolsThe performance characteristics of carbide cutting tools are as follows:① High hardness: Carbide cutting tools are made of carbides with high hardness and melting point (called hard phase) and metal binders (called bonding phase) through powder metallurgy, with a hardness of 89 to 93HRA. , much higher than high-speed steel. At 5400C, the hardness can still reach 82~87HRA, which is the same as the hardness of high-speed steel at room temperature (83~86HRA). The hardness value of cemented carbide changes with the nature, quantity, particle size of carbides and the content of the metal bonding phase, and generally decreases with the increase in the content of the bonding metal phase. When the binder phase content is the same, the hardness of YT alloys is higher than that of YG alloys, and alloys added with TaC (NbC) have higher high temperature hardness.② Bending strength and toughness: The bending strength of commonly used cemented carbide is in the range of 900 to 1500MPa. The higher the metal binder phase content, the higher the flexural strength. When the binder content is the same, the strength of YG type (WC-Co) alloy is higher than that of YT type (WC-TiC-Co) alloy, and as the TiC content increases, the strength decreases. Cemented carbide is a brittle material, and its impact toughness at room temperature is only 1/30 to 1/8 that of high-speed steel.⑶ Application of commonly used carbide cutting toolsYG alloys are mainly used for processing cast iron, non-ferrous metals and non-metallic materials. Fine-grained cemented carbide (such as YG3X, YG6X) has higher hardness and wear resistance than medium-grained carbide with the same cobalt content. It is suitable for processing some special hard cast iron, austenitic stainless steel, heat-resistant alloy, Titanium alloy, hard bronze and wear-resistant insulating materials, etc.The outstanding advantages of YT type cemented carbide are high hardness, good heat resistance, higher hardness and compressive strength at high temperatures than YG type, and good oxidation resistance. Therefore, when the knife is required to have higher heat resistance and wear resistance, a grade with a higher TiC content should be selected. YT alloys are suitable for processing plastic materials such as steel, but are not suitable for processing titanium alloys and silicon-aluminum alloys.YW alloy has the properties of YG and YT alloys, and has good comprehensive properties. It can be used to process steel, cast iron and non-ferrous metals. If the cobalt content of this type of alloy is appropriately increased, the strength can be very high and can be used for rough machining and interrupted cutting of various difficult-to-machine materials.