Titanium various properties make it become the powerful attraction of component materials, but many of these attributes also affects its machinability. Titanium alloy is commonly used in industry for two-phase titanium alloys, namely (alpha beta) titanium alloy, in TC4, TC6 is commonly used in aircraft engine fuel accessories, including TC4 is a typical representative of this kind of alloy.
Titanium various properties make it become the powerful attraction of component materials, but many of these attributes also affects its machinability. Titanium alloy is commonly used in industry for two-phase titanium alloys, namely (alpha beta) titanium alloy, in TC4, TC6 is commonly used in aircraft engine fuel accessories, including TC4 is a typical representative of this kind of alloy. Titanium alloy material, high hardness and cutting performance is poor, and easy to produce work hardening phenomenon, brought difficulties to machining. For titanium alloy TC4 in this kind of material of the parts, especially the turning processing craft, catic west point to do a thorough research, and achieved some experience.
First of all, the elastic modulus of titanium alloy is small, the elastic modulus E of TC4 = 110 gpa, approximately half of the steel, and low thermal conductivity, which caused by cutting force the work piece of elastic deformation is large, at the same time can produce high and relatively concentrated in the manufacturing process of cutting force. So there was a tremor, prone to vibration caused by cutting lower precision of workpiece, thus to improve the machining system rigidity.
Second, in the machining of titanium alloy produced by the local high temperature, it is easy to absorb the oxygen and nitrogen in the atmosphere of titanium, thus forming the outside of hard and brittle. This can cause work hardening phenomenon on the surface of the workpiece processing, and work hardening speed, makes the tool surface have serious scratches and is easy to collapse edge phenomenon in cutting process.
In addition, the physical and chemical properties of titanium alloy material itself make its machining affinity with the workpiece, cutting tool and workpiece contact phenomena are prone to stick the knife, increasing the friction between cutter and workpiece, produce large amounts of heat cutting. The resulting a large number of distributed heat cutting can be collected through the chip, greatly reduce the service life of the cutting tool. So the processing of titanium alloy cutting tools must possess high hardness.
The titanium alloy processing can be seen as a system engineering, need from processing equipment, cutting tools and cutting parameters, such as cooling fluid considering a number of angles. In terms of processing equipment, the titanium alloy processing need machine processing performance is good, cool enough, so the machining equipment selection of high precision CNC lathes, machining spindle vibration when the tiny machining stability is good.
For better hardness and wear resistance of titanium alloy processing cutting tool material, has excellent heat resistance, at high temperatures can maintain high strength and toughness, as well as the damage resistance and impact resistance. Satisfies the requirements of the cutter has: ceramic cutting tool, coated carbide tool, cubic boron nitride (CBN) tool and diamond cutting tool (PCD) etc. Including coating cemented carbide cutting tools are cheap, and has good thermal conductivity and high hardness, also performed well in such aspects as red hardness and toughness, although than ceramic, cubic boron nitride (CBN), class, thermal stability and chemical stability of diamond tool is less, but better than the ceramic and class diamond tool with high impact resistance and damage resistance. Therefore has become a preferred processing titanium alloy cutting tools.