carbide tool is made of high hardness and melting point of carbide (called hard phase) and metal binder (called bonding phase) by powder metallurgy method, the hardness of 89 ~ 93HRA, far higher than high speed steel, at 5400C, hardness can reach 82 ~ 87HRA, and high speed steel at normal temperature hardness (83 ~ 86HRA) the same.The hardness of cemented carbides varies with the properties, quantity, particle size of carbides and the content of metal bonded phase, and generally decreases with the increase of the content of metal bonded phase.At the same content of bonded phase, the hardness of YT alloy is higher than that of YG alloy, and the alloy with TAC (NbC) added has higher hardness at high temperature.
Flexural strength and toughness:
the flexural strength of cemented carbide is in the range of 900 ~ 1500MPa.The higher the content of metal bonding phase, the higher the bending strength.When the content of adhesive is the same, the strength of YG type (WC-Co) alloy is higher than that of YT type (WC-TiC-Co) alloy, and the strength decreases with the increase of TiC content.Cemented carbide is brittle material, and its impact toughness is only 1/30 ~ 1/8 of high speed steel at normal temperature.
The application of cemented carbide cutting tools is commonly used
Class YG alloys are mainly used for processing cast iron, nonferrous metals and nonmetallic materials.Fine grain cemented carbide (such as YG3X, YG6X) in the amount of cobalt at the same time than the middle grain hardness and wear resistance to be higher, suitable for processing some special hard cast iron, austenitic stainless steel, heat resistant alloy, titanium alloy, hard bronze and wear-resistant insulation materials.
The outstanding advantages of YT type cemented carbides are high hardness, good heat resistance, high hardness and compressive strength at high temperature than YG type, good oxidation resistance.Therefore, when the knife is required to have higher heat resistance and wear resistance, the grade with higher TiC content should be selected.YT alloy is suitable for processing plastic materials such as steel, but not titanium alloy, silicon aluminum alloy processing.
YW alloy has the properties of YG and YT alloy and has good comprehensive performance. It can be used for processing steel material, cast iron and non-ferrous metals.This kind of alloy, with appropriate increase of cobalt content, has high strength and can be used for rough machining and intermittent cutting of a variety of difficult to machine materials.