Selection of cutting fluid

tool steel
Its heat resistance temperature is about 200-300 ℃, and it can only be used for cutting general materials. It will lose its hardness at high temperatures. Due to the poor heat resistance of this type of cutting tool, it is required that the cooling effect of the coolant be good, and emulsion is generally preferred.
high speed steel
This material is a high-grade alloy steel based on chromium, nickel, tungsten, molybdenum, vanadium (some even contain aluminum), and their heat resistance is significantly higher than that of tool steel, with a maximum allowable temperature of up to 600 ℃. Compared with other high-temperature resistant metal and ceramic materials, high-speed steel has a series of advantages, especially its high toughness, suitable for geometrically complex workpieces and continuous cutting processing. Moreover, high-speed steel has good machinability and is easily accepted in price. When using high-speed steel cutting tools for low-speed and medium speed cutting, it is recommended to use oil-based cutting fluids or emulsions. During high-speed cutting, due to the high heat generation, it is advisable to use water-based cutting fluid. If oil-based cutting fluid is used, it will produce a lot of oil mist, pollute the environment, and easily cause workpiece burns, decreased machining quality, and increased tool wear.
Hard alloy
The hard alloy used for cutting tools is composed of tungsten carbide (WC), titanium carbide (TiC), tantalum carbide (TaC), and 5-10% cobalt. Its hardness greatly exceeds that of high-speed steel, and the maximum allowable working temperature can reach 1000 ℃. It has excellent wear resistance and can reduce the bonding phenomenon between chips when processing steel materials. When selecting cutting fluids, the sensitivity of hard alloys to sudden heating should be considered, and the tool should be heated evenly as much as possible, otherwise it may lead to edge breakage. When processing general materials, dry cutting is often used. However, during dry cutting, the temperature rise of the workpiece is relatively high, which makes it prone to thermal deformation and affects the machining accuracy of the workpiece. Moreover, cutting without lubricants increases power consumption and tool wear due to high cutting resistance. Hard alloy cutting tools are relatively expensive, so from an economic perspective, dry cutting is also not cost-effective. When selecting cutting fluids, the thermal conductivity of oil-based cutting fluids is generally poor, and the risk of sudden tool cooling is lower than that of water-based cutting fluids. Therefore, it is generally advisable to choose oil-based cutting fluids containing anti-wear additives. When using coolant for cutting, it is important to cool the tool evenly. Before starting cutting, it is best to cool the tool with coolant beforehand. For high-speed cutting, it is necessary to spray the cutting area with a large flow rate of cutting fluid to avoid uneven heating of the tool and the occurrence of edge breakage. It can also reduce the oil fume pollution caused by evaporation due to high temperature.
ceramics
Made by sintering alumina, metals, and carbides at high temperatures, this material has better high-temperature wear resistance than hard alloys. Generally, dry cutting is used, but water-based cutting fluid is also commonly used to ensure uniform cooling and avoid high temperatures.
diamond
It has extremely high hardness and is generally used for cutting. To avoid high temperatures, like ceramic materials, water-based cutting fluids are often used in many cases.