Coated hard alloy cutting tools are the preferred choice for machining titanium alloys

The various properties of titanium make it a highly attractive component material, but many of these properties also affect its machinability. The commonly used titanium alloys in industry are two-phase titanium alloys, namely (α β) titanium alloys. TC4 and TC6 are commonly used in aviation engine fuel accessories, with TC4 being a typical representative of this type of alloy.

The various properties of titanium make it a highly attractive component material, but many of these properties also affect its machinability. The commonly used titanium alloys in industry are two-phase titanium alloys, namely (α β) titanium alloys. TC4 and TC6 are commonly used in aviation engine fuel accessories, with TC4 being a typical representative of this type of alloy. Titanium alloy materials have high hardness, poor cutting performance, and are prone to work hardening, which poses difficulties for cutting. AVIC West Control has conducted in-depth research on parts made of TC4 materials in titanium alloys, especially in turning processes, and has gained some experience.

Firstly, the elastic modulus of titanium alloy is small, with TC4 having an elastic modulus of E=110GPa, which is about half that of steel. En plus, its thermal conductivity is low, resulting in significant elastic deformation of the workpiece caused by cutting forces. En même temps, high and concentrated cutting forces are generated during the machining process. This can easily cause vibration and vibration during cutting, reducing the accuracy of the workpiece. Therefore, it is necessary to improve the rigidity of the machining system.

Secondly, the local high temperature generated by titanium alloy during cutting makes it easy for titanium to absorb oxygen and nitrogen from the atmosphere, thus forming a hard and brittle outer skin. This will cause work hardening on the machining surface of the workpiece, and the work hardening speed is fast, resulting in serious scratches on the tool surface, which is prone to chipping during the cutting process.

In addition, the physical and chemical properties of titanium alloy materials themselves make them highly compatible with the workpiece during cutting. When the cutting tool comes into contact with the workpiece during cutting, it is prone to sticking, increasing the friction between the tool and the workpiece and generating a large amount of cutting heat. The large amount of cutting heat generated as a result cannot be dissipated through the chips in a timely manner, greatly reducing the service life of the tool. Therefore, cutting tools for processing titanium alloys must have high thermal hardness.

The processing of titanium alloy here can be regarded as a systematic engineering, which requires consideration from multiple perspectives such as processing equipment, cutting tools, cutting parameters, coolant, etc. In terms of processing equipment, titanium alloy processing requires machine tools with good processing performance and sufficient cooling, so CNC lathes with high processing accuracy are selected for processing equipment. The spindle vibration is minimal during processing, and the processing stability is good.

The tool materials used for titanium alloy processing have good hardness and wear resistance, excellent heat resistance, high strength and toughness at high temperatures, as well as certain impact and damage resistance. Tools that meet the above requirements include ceramic tools, coated hard alloy tools, cubic boron nitride tools (CBN), and diamond-like carbon tools (PCD). Among them, coated hard alloy cutting tools are inexpensive, have good thermal conductivity and high hardness, and also perform well in red hardness and toughness. Although their heat resistance and chemical stability are inferior to ceramic, cubic boron nitride (CBN), and diamond-like cutting tools, they have higher impact resistance and damage resistance than ceramic and diamond-like cutting tools. Therefore, it has become the preferred cutting tool for processing titanium alloys. Coated hard alloy cutting tools are the preferred choice for machining titanium alloys