Whether it is cutting or forming, various forms of friction and a large amount of heat are generated in the operation. In most cases, Metal Working Fluid that plays the role of lubrication and cooling must be added to improve the friction state and take away most of the heat generated, so that the processing can be carried out normally and the service life of the tool or mold can be extended. With the rapid development of metal processing and the increasing amount of cutting, high-performance cutting fluid has become an indispensable part of metal processing technology. We must understand these nine properties.
1. Lubricity The friction and wear occurring in the cutting process is more complex, which includes fluid lubrication, boundary lubrication, mixed lubrication between fluid lubrication and boundary lubrication, and elastic fluid lubrication. Different cutting processes, the same cutting process but different cutting speeds, different workpiece materials, the proportion of various lubrication forms is not the same, so it is very difficult to meet the lubrication requirements of metal working fluid. 2. Cooling property Due to the large amount of heat generated in metal processing, the temperature of high-speed steel tools in cutting can reach 260~500 ℃, and the temperature of tungsten carbide tools can reach 427~650 ℃. It is required that the metal working fluid has good cooling performance. 3. Wettability and permeability In cutting, the friction should occur before the lubricant arrives. If the lubricant cannot reach the friction area in time, the performance of the lubricant is useless. Therefore, how to make the lubricant play a role in the friction area in time is very important, but the fact is that the lubricant does improve the friction state, indicating that the lubricant has reached this area when friction occurs. Many people have studied this phenomenon, some think it is capillary action, some think it is penetration or extrusion, but regardless of the conclusion, the metal working fluid is required to have good permeability. Of course, in this regard, appropriate lubricant supply methods should be used, such as high-pressure spraying, oil bath, soaking, etc.
4. Rust resistance The machined workpiece surface is the fresh surface of the material, without any protection, and is extremely vulnerable to environmental attack and damage. (First, the oxygen and humidity in the air will cause the metal on the surface to generate oxides or rust; second, the additives in the cutting fluid, especially the extreme pressure additives, contain a lot of active sulfur or chlorine, and can also generate sulfide or chloride with loose texture with the metal.) The metal processing fluid should have a certain protective performance, Make the workpiece rust proof between processes. 5. Foaming resistance The additives of the metal working fluid contain more surfactants, some of which will promote the formation of foam, while the metal working fluid will entrain air during the flow and rotation of the workpiece or cutter, providing conditions for the formation of bubbles. The foam in the liquid will make the liquid supply discontinuous, reduce the cooling and lubrication, expand the contact area with the air to accelerate the decay of the liquid, so the metal working fluid should have good Anti Foam property. 6. Mould resistance The water-based metalworking fluid contains fatty organics and bacterial nutrients, which are easy to breed bacteria and stink during use, and should have strong mold resistance.
7. Low oil mist The metalworking fluid is also splashed into the surrounding environment in the rotary processing process of some workpieces or tools. The operator inhales or contacts with the skin for a long time, which affects the health of the body. In addition to strengthening the oil mist reduction measures, the metalworking fluid itself should also have the oil mist reduction function. 8. Cleanability After the last processing, some of them are packaged or assembled as finished products, and some are rust proof and painted. Before that, the processing lubricants on the workpiece surface should be removed with alkali, detergent, solvent and other cleaning processes. The existence of these lubricant films hinders the quality of rust prevention and painting, which requires that the metalworking fluid has a good cleaning performance.
9. Annealing detergency Some processes, such as non-ferrous metals, shall be annealed after rolling, and the treated metal surface shall be bright and clean, which requires that the lubricant has good volatility, low carbon residue, and no sediment can be left on the metal surface under high temperature.
