Difference between annealed and hot rolled titanium alloys

First, the concept of annealed state and hot rolled state
Titanium alloy is a kind of high strength, low density, corrosion resistant metal material, widely used in aviation, aerospace, metallurgy, chemical industry and other fields. Titanium alloys can be processed in a variety of ways to obtain different material states, among which annealed and hot rolled state is one of the common states.

The annealing state refers to the processing state where the titanium alloy is heated to a certain temperature and then slowly cooled to room temperature. In this process, the grain size of titanium alloy increases, the internal stress is released, the hardness of the material is reduced, and it has certain plasticity and toughness.

Hot rolled state refers to the processing state of titanium alloy after heating to high temperature, pressing and deformation on the roller table. In this process, the titanium alloy is subjected to strong plastic deformation, the grain size is refined, the hardness is increased, the mechanical properties and strength are improved.

Second, the difference in the degree of cold deformation
During the preparation of titanium alloys, cold deformation processing is often required to improve the material properties. The difference between annealed state and hot rolled state is mainly due to the difference in the degree of cold deformation.

Titanium alloys in annealed form usually undergo a small deformation to maintain their plasticity and toughness. The hot rolled titanium alloy is deformed greatly to improve its hardness and strength.

Third, the difference in grain size and hardness
The grain size of titanium alloy is an important parameter that affects the material properties. The smaller the grain size, the better the corrosion resistance of the material, the higher the strength and plasticity.

The grain size of the annealed titanium alloy is large, generally between 1-10 microns. Because the grain is re-grown during the annealing process, the hardness of the material is reduced. On the contrary, the hot rolled titanium alloy has a small grain, usually between 0.1-1 microns, and the material hardness and strength are relatively high.

Fourth, mechanical properties and application differences
The mechanical properties of titanium alloys are also directly affected by the state of the material. The strength and hardness of the annealed titanium alloy are relatively low, but it has good plasticity and toughness, which is suitable for manufacturing high-strength and high-toughness parts. The hot-rolled titanium alloy has higher strength and hardness, and is suitable for manufacturing high-strength and high-stiffness parts.

In addition, the application field of titanium alloys is also limited by the state of the material. For example, in equipment that needs to operate at high temperatures, hot-rolled titanium alloys are usually used because they can maintain high mechanical properties and high temperature oxidation resistance.