Due to titanium alloy contain a variety of alloy element, which contains some high activation energy element, its status in the alloy is relatively stable, so the titanium alloy in plastic deformation has great energy, also has certain processability. However, the thermal conductivity of titanium alloy is poor. In the cutting process, the cutting heat will be concentrated on the cutting tool. Therefore, the thermal load of titanium alloy material is large and the tool is damaged. Therefore, the common method to improve the production efficiency by increasing the amount of excision per unit time range is not suitable for the processing of titanium alloy materials. Therefore, the proper processing method should be chosen for different titanium alloy materials.
(1) titanium alloy has high strength, high toughness and high hardness, so it has a serious hardening problem during cutting and processing, which requires annealing. Especially when there is a scratch or cut workpiece surface, because it is sensitive to strain rate, prone to scratches or cracks in the process of machining, so must control the machining speed, with low speed.
Generally, titanium alloy has good thermal stability and high temperature resistance. Compared with aluminum alloy, the strength of titanium alloy is much higher. When cutting, the thermal conductivity of titanium alloy is very low, equivalent to a small part of iron and aluminum materials, and its heat is concentrated on the cutting edge. When the temperature exceeds a certain standard, can produce Gao Huaxue activity, react with hydrogen and oxygen in the air, thus reducing its plasticity, when in contact with the blade and chip will increase of tool wear.
(3) cutting, because there is friction between titanium alloy and tool, with the increase of friction velocity, the higher the temperature is, the greater the power, tool wear, and easy to bond, thus greatly shorten the service life of cutter. Therefore, the reasonable selection of cutting tools is also very important, usually choose some hard alloy materials such as tungsten cobalt carbide tools. In this way, the adverse stress can be effectively prevented and the precision of component can be guaranteed.
These characteristics of titanium alloy in the cutting process make it very difficult to machining, which leads to lower production efficiency and higher production cost. Therefore, in the machining process of titanium alloy, it is necessary to improve the processing scheme and adjust the reasonable processing parameters so as to improve the processing quality of titanium alloy.
