Different functions of various additives in metalworking fluid!
January 13, 2023
The function of metalworking fluid is to provide lubrication, cooling, chip removal and rust prevention effects for metal cutting, grinding and forming, so as to obtain good surface accuracy and processing quality, and extend the service life of tools and machine tools. The water-based metalworking fluid can also inhibit the propagation of microorganisms and prevent rancidity. Metalworking fluids are divided into pure oil, soluble oil, semi synthetic and fully synthetic fluids, in which different additives are added to meet different processing needs.
1. Cutting oil Cutting oil is a mineral oil or vegetable oil product that does not need to be diluted with water. Cutting oil can be mineral oil or vegetable oil itself, or it can be a composite of Base Oil and various additives. It is often used for difficult cutting and forming. When stretching, viscous oil is usually used to form a stronger hydrodynamic film. 1.1 Base oil The most basic cutting oil is composed of pure oil or naphthenic base oil with 10% - 40% boundary lubricant. These boundary lubricants can be animal oil (lard, butter, etc.) or vegetable oil (palm oil, coconut oil, etc.). These additives are usually used for light duty machining. 1.2 Functional additives For difficult processing, additives containing sulfur, chlorine and phosphorus need to be added to mineral oil. These additives can be used alone or in combination. 1.3 Chlorination additive The chlorination additive can be chlorinated paraffin, chlorinated olefin or chlorinated ester. Chlorinated additives will not cause metal discoloration, but will release a small amount of hydrogen chloride to corrode the metal. At the same time, chlorides usually have an impact on health, so their use is restricted. 1.4 Vulcanizing additive Vulcanizing additives are divided into active sulfur and inactive sulfur. If the additive contains active sulfur, the free sulfur element is easy to react with the metal surface, making the yellow metal discolor. Therefore, additives containing active sulfur are not suitable for copper processing. If the additive contains inactive sulfur, it is not easy to cause metal discoloration. Sulfide additives are generally used for tapping, thread turning and other difficult machining. 1.5 Phosphating additive Phosphating additives can work at low temperatures, but their lubricating properties are lower than those of sulfur and chlorine additives. At the same time, phosphide is the nutrient of microorganisms, which is easy to cause microbial reproduction. 1.6 Solid additives Commonly used are graphite, molybdenum disulfide, etc.
2. Soluble oil Soluble oil or emulsified oil is commonly used in metal processing. It is composed of base oil, emulsifier and special additives. Soluble oil has low cost, good cooling property and is suitable for high-speed machining. When soluble oil is mixed with water, different concentrations are used for different processing methods. 2.1 Base oil It is usually naphthenic base oil or paraffin base oil, or vegetable oil. 2.2 Emulsifier The most commonly used emulsifier is sodium sulfonate, which can be a non-ionic emulsifier such as ethoxy alcohol. The function of emulsifier is to disperse small droplets of oil in water to form an emulsion that is white to translucent. 2.3 Functional additives ● Anti rust agent: Calcium Sulfonate, alkanolamide, oxidized wax, boric acid, etc. ● pH buffer: amine ● Fungicides ● Defoamer
3. Semi synthetic metalworking fluid Semi synthetic processing fluids, like soluble oils, are water based fluids. Although semi synthetic processing fluid is usually clear and transparent in appearance, it contains 5% - 30% mineral oil. Emulsifiers and functional additives are mostly the same as those used for soluble oils. 4. Fully synthetic metalworking fluid Fully synthetic processing fluid is a water-based product without mineral oil, which is composed of a large number of rust inhibitors and lubricating additives. It is usually used for various cutting, grinding and forming processes, and is suitable for processes with good cleaning requirements, long service life and moderate lubrication.
