Why is titanium alloy a difficult-to-process material

The physical phenomenon of titanium processing The cutting force of titanium alloy processing is only slightly higher than that of steel of the same hardness, but the physical phenomenon of processing titanium alloy is much more complicated than processing steel, which makes titanium alloy processing face huge difficulties. The thermal conductivity of most titanium alloys is very low, only 1/7 that of steel and 1/16 that of aluminum. Therefore, the heat generated in the process of cutting titanium alloy will not be quickly transferred to the workpiece or taken away by the chips, but will be concentrated in the cutting area. The temperature generated can be as high as 1,000°C, causing the cutting edge of the tool to quickly wear, crack and Generate built-up edge, wear out the cutting edge quickly, and generate more heat in the cutting area, further shortening the life of the tool. The high temperature generated during the cutting process also destroys the surface integrity of the titanium alloy parts, resulting in a slight decrease in accuracy of the parts and a work hardening phenomenon that severely reduces the fatigue strength of the parts. The elasticity of titanium alloy may be beneficial to the performance of parts, but in the cutting process, the elastic deformation of the workpiece is an important cause of vibration. The cutting pressure causes the 'elastic' workpiece to leave the tool and rebound, so that the friction between the tool and the workpiece is greater than the cutting action. The friction process also generates heat, which aggravates the problem of poor thermal conductivity of titanium alloys. This problem is even more serious when processing thin-walled or ring-shaped parts that are easily deformed. It is not an easy task to process thin-walled titanium alloy parts to the expected dimensional accuracy. As the workpiece material is pushed away by the tool, the local deformation of the thin wall has exceeded the elastic range and plastic deformation occurs, and the material strength and hardness of the cutting point are obviously increased. At this moment, machining according to the originally determined cutting speed becomes too high, which further leads to sharp tool wear. Starting with the blade to deal with the difficult problem of titanium processing The groove wear of the blade during titanium alloy processing is the local wear of the back and the front along the depth of cut, which is often formed by the hardened layer left by the previous processing. The chemical reaction and diffusion of the tool and the workpiece material at a processing temperature of more than 800 ℃ is also one of the reasons for the formation of groove wear. In the process of processing, the titanium molecules of the workpiece accumulate in the front area of u200bu200bthe blade and are 'welded' to the blade under high pressure and high temperature, forming a built-up edge. When the built-up edge is peeled from the blade, the carbide coating of the blade is taken away. Therefore, titanium alloy processing requires special blade materials and geometric shapes. Tool structure suitable for titanium processing The focus of titanium alloy processing is heat. Many high-pressure cutting fluids must be sprayed on the cutting edge in time and accurately to quickly remove the heat. There is a unique structure of milling cutter specially used for titanium alloy processing on the market.