What kind of cutting fluid is suitable for titanium alloy?
March 22, 2023
Due to its low density, high specific strength, high temperature resistance, good oxidation resistance and other characteristics, titanium alloy has poor thermal conductivity, which requires high cooling characteristics and excellent lubricity. When cutting titanium alloy, in order to reduce the cutting temperature, a large amount of cutting fluid with cooling effect should be poured into the cutting area. The requirements for cutting fluid include high thermal conductivity, high specific heat capacity, high heat capacity, high heat of vaporization, high vaporization speed, high flow rate and high flow rate. Generally speaking, the thermal conductivity of water is 3~5 times greater than that of oil, the specific heat capacity is 1 times greater, and the heat of vaporization is almost 10 times greater.
For titanium alloys, which are inherently difficult to machine, special cutting fluid for titanium alloys must be used for machining. 1. It has excellent anti-rust, cooling and lubricating properties. 2. It also has a strong and tough oil film, which can provide excellent protection, cooling and lubrication effects for the blade, and can ensure extremely high feed rate and cutting rate to achieve perfect surface quality, extend the tool service life and prevent the generation of tool bumps; 3. Excellent machining finish and precision; Good fluidity, outstanding permeability and good chip removal ability; 4. No oil mist, greatly reducing the impact of working environment on health. The special cutting fluid for titanium alloy can solve the machining problem of titanium alloy, which is difficult to machine.
The above is a conventional view, but also limited to the factors of processing equipment. The latest research results show that the heat of titanium alloy processing particles is extremely high, and the local heat generated is very large. Although the cooling performance of water-soluble cutting fluid is preferred, it has vaporized before reaching the cooling area. In fact, the average temperature of the central area using water-soluble cutting fluid is more than twice that using oil-based cutting fluid, and the cutting process results are not ideal. However, due to the limitations of viscosity and flash point, pure oil cutting fluid is obviously not suitable for high-speed machining, and the risk of fire is difficult to control. The titanium alloy cutting fluid cannot use the fontanel substance "chlorine" with fire extinguishing performance. Because high temperature will decompose and release hydrogen during cutting, which will be absorbed by titanium and cause hydrogen embrittlement, and may also cause high temperature stress corrosion cracking of titanium alloy. Because the chlorides in the cutting fluid may also decompose or volatilize toxic gases during use, safety measures must be taken during use, otherwise the use should be strictly prohibited. After cutting, the parts shall be thoroughly cleaned with chlorine-free detergent in time to remove chlorine-containing residues. Therefore, the supplier shall be required to avoid chlorine in the cutting fluid components when cutting titanium alloy.
If conditions permit, better lubrication and cooling effect can be obtained by using MQL atomization micro-lubrication to cut titanium alloy. Through MQL special equipment, the trace oil with extreme pressure lubrication capacity is fully mixed with compressed air to form aerosols, which are sprayed into the processing area at high pressure, avoiding the risk of fire than the pouring supply of oil-based cooling pure oil, and more than three times deeper than the water-soluble cutting fluid into the core cutting area. It has been proved by practical records that MQL micro-lubrication can extend the tool life by 8 times, and the same processing parameters can improve the machining accuracy by 1 level.
