What if the metalworking oil rusts? Here is the answer you want
February 24, 2023
Rust of metalworking oil Cutting oil is often used in metal processing and treatment process. How to prevent metal from corrosion and corrosion during processing is an important performance index of metal processing oil. Corrosion is a chemical reaction of partial or total stripping, dissolution or softening of metal surface. "Corrosion" includes not only ferrous metals, but also other non-ferrous metals. Generally, the corrosion problems encountered in the process of metal processing can be divided into two situations: the rust of the machine tool after long-term use and the corrosion of the processed metal products. The metal processing oil should solve two aspects of corrosion problems: preventing the corrosion of the processed metal objects and preventing the corrosion of the machine parts (metal parts that complete the processing task). There are four kinds of metals most common in industry, steel, aluminum, magnesium and titanium.
What factors will cause metal corrosion and corrosion? In addition to the components of the metalworking oil itself, the factors affecting corrosion include water/humidity, temperature, air quality, whether the oil is contaminated (acid, salt, other liquids such as chemical liquids, other oils, etc.), bacteria, etc., which will lead to uneven concentration in different areas of the metal surface, cracks and nicks on the metal surface, or galvanic corrosion between dissimilar metals. Corrosion problems in metal processing Rust problem of steel: Iron and steel are the most common metals with low price and high strength, and the disadvantage is easy to corrode (rust). The corrosion inhibitors commonly used in metalworking oil include amine compounds. Amines are critical to the antirust ability. Pay attention to check the content of amine when testing. In actual use, the factors affecting this performance include poor water quality, high bacterial content, high humidity, and acid in the air. Solution: The use of oily cutting oil can prevent the occurrence of steel rust on the premise of ensuring the processing quality. Corrosion of aluminum: The density of aluminum is only about 1/3 of that of iron. The advantage is that it is not easy to corrode. However, in some cases, aluminum will corrode, such as contacting with some metal salts (such as chlorides), high PH value, and contacting with other metals to form galvanic corrosion. The common corrosion inhibitors of aluminum metal processing oil include silicate and phosphate ester. Solution: using sulfurized lard as the main extreme pressure additive and reducing the proportion of chlorinated paraffin can effectively prevent aluminum corrosion. Corrosion problems in magnesium processing: The density of magnesium metal is smaller than that of aluminum (2/3 of aluminum), but its strength is good. Magnesium has two disadvantages: flammability, active chemical properties, and reaction with water to generate hydrogen, which is flammable and explosive. This problem is particularly important when using water-based processing fluids. Solution: Metal processing oil can be used to react with magnesium sheet to collect and measure the volume of hydrogen generated, so as to judge the strength of the reaction between metal processing oil and magnesium. In addition, attention should be paid to the corrosion degree of magnesium sheet. Corrosion of titanium metal: Titanium has the advantages of low density, high strength, the highest strength-weight ratio and corrosion resistance. However, the thermal conductivity is poor, so the heat dissipation capacity is poor. During processing and cutting, heat is easily concentrated on the cutting surface and contact surface. The elasticity of titanium metal is very good, which means that during processing, titanium material is easy to spring away and deviate from the force during processing, unless the force is large during processing. Titanium is corrosion resistant, but it is easy to cause stress corrosion and cracking under high temperature. Solution: The precision cutting oil for processing titanium alloy can be used to provide excellent extreme pressure and anti-wear performance and ensure product quality under the premise of protecting the machine tool equipment.
