Titanium alloy is a widely used metal material due to its low density, high specific strength, excellent corrosion resistance, high heat resistance, toughness, plasticity and weldability. Its applications are wide-ranging, including aerospace, automotive, medical, sporting goods, and electrolysis industries. However, its high hardness, low thermal conductivity, and low modulus of elasticity can pose a challenge in processing the material. Thus, this paper presents different measures in cutting and processing titanium alloy based on its unique process characteristics.
The main advantages are as follows.
1. Titanium alloy has high strength and low density (4.4kg/dm3), lightweight, for some large structural parts to reduce the weight of the solution.
Titanium alloy possesses remarkable thermal strength as compared to aluminum alloy. It can retain high strength even at temperature ranges of 400 to 500℃ and performs with great stability. On the contrary, aluminum alloy can only operate at a working temperature that is not more than 200℃.
Titanium alloy possesses a superior inherent corrosion resistance as compared to steel. This particular quality of titanium alloy ensures lower costs related to the routine maintenance and operation of the aircraft.
The characteristics of titanium alloy processing are mainly as follows.
With a thermal conductivity that is only 1/4 of steel and 1/13 of aluminum, tc4 experiences poor heat dissipation and cooling effects during cutting processes. Copper exhibits a thermal conductivity that is 1/25 of tc4. As a result, using tc4 can shorten the lifespan of cutting tools due to its low ability to dissipate heat.
The low modulus of elasticity in materials can cause issues during machining as the surfaces can rebound, leading to an increase in contact area between the tool and machined surface. This can result in a reduction in the tool's durability and compromised dimensional accuracy of the parts being machined.
3. Hardness factor. The low hardness value of titanium alloy processing will be sticky, chip stained on the cutting edge near the front surface of the tool to form a chip tumor, affecting the processing effect; the high hardness value of titanium alloy processing is easy to make the tool produce chipping and abrasion. These characteristics lead to the titanium alloy metal removal rate being low, only 1/4 of the steel parts, and the processing time being much longer than the same size steel parts.
The chemical affinity of titanium is noteworthy, as it can readily chemically react with air's principal components, such as nitrogen, oxygen, and carbon monoxide. This interaction creates a TiC and TiN hardened layer on the surface of the alloy, providing increased durability and enhanced protection. However, when exposed to high temperatures, titanium can also react with the tool material, which ultimately causes a reduction in tool durability. Therefore, it is essential to consider the potential reactions of titanium when selecting a tool material to ensure long-lasting applications.
5. Inadequate safety performance during the cutting process. Titanium is a combustible metal, and the high temperatures and sparks generated during the micro-cutting process may cause titanium chips to ignite.