The development of diamond tool material plays a decisive role in the progress of cutting technology. This paper mainly introduces the properties and application range of diamond, polycrystalline cubic boron, ceramic, hard alloy and high speed steel used in cutting. Cutter damage mechanism is the theoretical foundation of the cutting tool material selection reasonable, performance with rational matching of cutting tool material and workpiece material is the key basis of cutting tool materials according to the cutting tool material and workpiece material mechanics, physical and chemical properties of selection cutting tool material, good cutting effect can be attained. The selection of cutter material for piston during machining is described. High speed steel: milling, milling, milling and expansion slot milling cutter in piston machining, drilling hole with drill bit and so on are high speed steel material. Cubic boron nitride: the cubic boron nitride cutter is used in the casting iron ring groove process of the cast iron ring piston. It is also used in the machining of piston stereo.
Diamond, diamond cutting tools can use diamond material of high hardness, high wear resistance, high thermal conductivity and low friction coefficient of non-ferrous metals and non-metallic materials wear-resisting high precision, high efficiency, high stability and high surface finish machining. In cutting aluminum alloy, the PCD cutting tool is the life of a cemented carbide cutting tools of dozens of times and even hundreds, is the ideal of aluminum piston precision machining tool, has been used in finish turning ring grooves, fine boring piston pin hole, fine car live the Great Wall, essence of piston top surface fine car piston combustion chamber and the finishing process.
The performance of tool material is the basic factor that affects the surface quality, cutting efficiency and tool life. When cutting, it is the cutting part of the cutting tool directly. The cutting performance of the tool depends on the material, the geometry parameters of the cutting part and the choice and design of the tool structure. Machining of the high and low productivity and tool life, cutting tool consumption and processing costs how much, the merits of the machining accuracy and surface quality, etc., to a large extent depends on selection of proper cutting tool materials. Choosing tool material correctly is one of the important contents of designing and selecting tool.
Each variety of tool material has its specific machining range, which can only be applied to certain workpiece materials and cutting speed range. Different tool materials and the same tool life when machining different workpiece materials tend to have very big difference, such as: machining aluminum piston, the service life of diamond tool is yg carbide tool life several times to dozens times; The life of yg carbide tool is also very different when it is processed with high silicon content, medium and low aluminum alloy. Therefore, rational selection of cutting tools is the key to successful machining. Each tool material has its best processing object, which is the reasonable matching problem of cutting tool and processing object.
Hardness is the basic characteristic of tool material. The tool must be cut from the workpiece and the hardness of the tool must be greater than that of the workpiece material. The cutting edge hardness of cutting tools is usually above 60hrc. Wear resistance is the material's ability to resist wear. Generally speaking, the higher the hardness of the tool material, the better the wear resistance. The smaller the hard particles in the tissue, the more uniform the distribution, the better the wear resistance. Wear resistance is also related to the chemical composition, strength, microstructure and temperature of the friction zone. The formula can be used to represent the wearability of the material.
To make the cutting tool under a lot of pressure, as well as the impact and vibration in cutting process is often under the working conditions, and does not produce collapse and broken blade, cutting tool material, you must have enough strength and toughness.
High heat resistance material cutting performance of the main mark. It refers to the performance of the tool material under high temperature conditions to maintain a certain hardness, wear resistance, strength and toughness.
The tool material should also have the ability to resist oxidation at high temperature and good anti-bonding and anti-diffusion ability, that is, the tool material should have good chemical stability.
When cutting or using cutting fluid, the cutter is often subjected to a large thermal shock. The ability of tool material to resist thermal shock can be expressed by the thermal shock coefficient r. The definition of r is:
The thermal conductivity is large, so that the heat can be easily dispersed, and the temperature gradient on the tool surface is reduced. The thermal expansion coefficient is small, which can reduce heat distortion. The elastic modulus is small, which can reduce the amplitude of alternating stress due to thermal deformation. It is beneficial to improve the thermal shock resistance of materials.
