Titanium is a new type of metal, alloy hardness greater than HB350 particularly difficult machining

Titanium is a new type of metal, alloy hardness greater than HB350 particularly difficult machining, less than HB300 is prone to stick a knife phenomenon, but also difficult to cut. However, only one aspect of the hardness of titanium machining difficult, the key is the combined effect of its machinability of chemical, physical and mechanical properties of titanium foil itself between. Cutting Titanium has the following characteristics:
(1) deformation coefficient is small: This is a significant feature of titanium machining, deformation coefficient is less than or close to one. Chip away the knife sliding friction surface greatly increases the previous accelerated tool wear.
(2) high cutting temperatures: As low thermal conductivity of titanium alloy (equivalent to only 1/5 ~ 1/7 45 steel), the contact length of the chip and the rake is very short, the heat generated when cutting difficult to pass out, concentrated in a smaller range of the cutting area and near the cutting edge, high cutting temperatures. Under the same cutting conditions, the cutting temperature higher than 45 steel cutting more than doubled.
Cutting force (3) per unit area on the big: the main cutting force of about 20% smaller than when cutting steel, due to the length of the chip and the rake face contact is extremely short, the contact area on the cutting forces unit greatly increased, likely to cause chipping. Meanwhile, due to the small elastic modulus of the titanium plates alloy, the processing in the radial force prone to bending deformation, causing vibration, increased tool wear and affects the accuracy of parts. Therefore, the required process system should have good rigidity.
(4) Chilled serious: Because the chemical activity of titanium is large, at high cutting temperature, is easy to absorb oxygen in the air and nitrogen to form a hard and brittle skin; while plastic deformation during the cutting process can also cause surface hardening . Chilled phenomenon will not only reduce the fatigue strength of the parts, but also increased tool wear, is a very important feature when cutting titanium.