Processing Properties of Titanium And Titanium Alloys

Processing Properties of Titanium And Titanium Alloys

1. Machining performance

Titanium alloy has high strength and high hardness, so the processing equipment is required to have high power, and molds and tools should have high strength and hardness. During cutting, the contact area between the chip and the rake face is small, and the stress on the tool tip is large. Due to the low elastic modulus of titanium alloy, the workpiece has a large rebound during cutting, which may easily cause the aggravation of tool flank wear and deformation of the workpiece; the chemical activity of titanium alloy is very high at high temperature, and it is easy to react with gas impurities such as hydrogen and oxygen in the air. The chemical reaction produces a hardened layer, which further aggravates the wear of the tool; in titanium alloy cutting, the workpiece material is easily bonded to the tool surface, coupled with high cutting temperature, so the tool is prone to diffusion wear and adhesive wear.

2. Grinding performance

The chemical properties of titanium alloy are lively, and it is easy to be compatible with and adhere to the abrasive at high temperature, which will block the grinding wheel, resulting in increased wear of the grinding wheel, reduced grinding performance, and difficult to guarantee the grinding accuracy. Titanium alloy has high strength and high toughness, which makes it difficult to separate the grinding debris during grinding, increases the grinding force, and correspondingly increases the grinding power consumption. Titanium alloy has low thermal conductivity, small specific heat, and slow heat conduction during grinding, resulting in heat accumulation in the grinding arc area, resulting in a sharp increase in the temperature of the grinding area.

3. Extrusion performance

When extruding titanium and titanium alloys, high extrusion temperature and high extrusion speed are required to prevent excessive temperature drop, and at the same time, the contact time between the high-temperature billet and the mold should be shortened as much as possible. Due to the low thermal conductivity of titanium alloy, after the surface temperature drops, the heat of the inner billet cannot be transferred to the surface to supplement in time, and a surface hardened layer will appear, making it difficult to continue the deformation. At the same time, there will be a large temperature gradient between the surface layer and the inner layer. Even if it can be formed, it will easily cause deformation and uneven structure.

4. Forging performance

Titanium alloys are very sensitive to forging process parameters. Changes in forging temperature, deformation, deformation and cooling rate will cause changes in the microstructure and properties of titanium alloys. In order to better control the microstructure and properties of forgings, advanced forging technologies such as hot die forging and isothermal forging have been widely used in the forging production of titanium alloys in recent years. Conventional forging must be done with minimal cooling inside the forging die. The content of interstitial elements (such as O, N, C) also has a significant impact on the forgeability of titanium alloys.

5. Casting process performance

Due to the high chemical activity of titanium and titanium alloys, it is easy to react violently with N, O, and N in the air, and it is easy to react chemically with refractory materials commonly used in casting. The casting of titanium and titanium alloys, especially the investment casting is much more difficult than the investment casting of aluminum and steel, and it needs special means to realize it. The chemical composition of the alloy must be adjusted according to the requirements of the casting process.