How to choose a cutting fluid for difficult-to-machine titanium alloys?
January 09, 2022
Titanium alloy has the characteristics of high specific strength, corrosion resistance, high temperature resistance and fatigue resistance. Titanium alloy of the same size weighs only 60% of steel, but it is stronger than alloy steel. Titanium alloys have been widely used so far, but cutting processing is by no means easy. It is often difficult to choose milling cutters for processing titanium alloys. The sticky cutters are not hard enough to break easily. It is a common public problem. Why is it so difficult to process titanium alloys? It has the following four processing characteristics: 1. Gas impurities (oxygen, nitrogen, hydrogen, etc.) are chemically active and easy to hybridize with gas; 2. Titanium alloy has low plasticity and is easy to deform during cutting; 3. Severe work hardening will occur when titanium alloy is processed; 4. Tungsten carbide is easy to form during the machining process to reduce the cutting performance.
How to choose the right cutting fluid when cutting titanium alloy? When cutting titanium alloys, there are generally two kinds of cutting fluids to choose from, namely emulsions and water-soluble cutting fluids with extreme pressure additives. The formula of extreme pressure emulsifier: petroleum sodium sulfonate 10%, oleic acid 3%, lead petroleum sulfonate 6%, triethanolamine 3.5%, chlorinated paraffin 4%, No. 20 motor oil 70.5%, chlorinated stearic acid 3% . The formula of water-soluble cutting fluid with extreme pressure additives: chlorinated fatty acid, polyvinyl chloride 0.5%-0.8%, trisodium phosphate 0.5%, triethanolamine 1%~2%, sodium nitrite 1.2%, water, and the rest. For drilling, reaming, reaming, broaching, tapping and other processes, extreme pressure soluble oils with greater lubrication should be used as cutting fluids, such as castor oil, oleic acid, sulfurized oil, and chlorinated oil. The cooling and lubrication method is best to adopt high-pressure spray cooling method, high-pressure internal cooling method, etc., so that it can play a good role in cooling and lubrication. The cutting fluid flow rate is not less than 15~20L/min.
