The differences between the annealed state and the hot-rolled state of titanium alloys

I. The Concepts of annealed state and hot-rolled state
Titanium alloy is a kind of metal material with high strength, low density and corrosion resistance, which is widely used in aviation, aerospace, metallurgy, chemical engineering and other fields. Titanium alloys can be processed in various ways to obtain different material states, among which annealed state and hot-rolled state are common states.

Annealed state refers to the processing state in which titanium alloy is heated to a certain temperature and then slowly cooled to room temperature. During this process, the grain size of titanium alloy increases, the internal stress is released, the material hardness decreases, and at the same time, it possesses certain plasticity and toughness.

Hot-rolled state refers to the processing state where titanium alloys are heated to high temperatures and then pressed and deformed on a roller conveyor. During this process, titanium alloys undergo intense plastic deformation, resulting in refined grain size, increased hardness, and improved mechanical properties and strength.

Ii. Differences in the degree of cold deformation

In the preparation process of titanium alloys, cold deformation processing is often required to improve the material properties. The main difference between the annealed state and the hot-rolled state lies in the degree of cold deformation.

Annealed titanium alloys usually undergo minor deformations to maintain their plasticity and toughness. The hot-rolled titanium alloy, on the other hand, undergoes significant deformation to enhance its hardness and strength.

Iii. Differences in grain size and hardness
The grain size of titanium alloys is an important parameter affecting the material properties. The smaller the grain size, the better the corrosion resistance of the material, and the higher the strength and plasticity.

The grain size of annealed titanium alloys is relatively large, generally ranging from 1 to 10 microns. Because during the annealing process, the grains grow back and the hardness of the material decreases at the same time. On the contrary, the grains of hot-rolled titanium alloys are fine, usually ranging from 0.1 to 1 micron, and the hardness and strength of the material are also relatively high.

Iv. Differences in Mechanical Properties and Applications
The mechanical properties of titanium alloys are also directly affected by the material state. Annealed titanium alloys have relatively low strength and hardness, but they possess good plasticity and toughness, making them suitable for manufacturing parts with high strength and high toughness. Hot-rolled titanium alloys, on the other hand, have higher strength and hardness, making them suitable for manufacturing parts with high strength and rigidity.

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