There are three elements about hot sizing: the right thermal temperature, the time to keep the temperature and the pressure of sizing. When hot sizing, engage a pressure to the part and just ensure the part is right attached into the matrix. Too much power for sizing is not necessary, on contract, it will make the matrix or worktable deformed. Therefore, about the result of hot sizing, there are mainly two ingredients to consider: temperature and time and temperature is the key factor. Only under certain temperature to initiate heat effect can resilience be eliminated. The so-called “Heat Specification” therefore mainly means the temperature and time for sizing.

Generally, a suitable specification for a certain type of titanium plate must ensure the part meets following basic requirements below after sizing:

1. The shape, surface quality and size of the titanium part should accord with the requirement of inspection.

2. The mechanical performance of the titanium material is basically stable and reach the standard of performance under the indoor temperature and using temperature.

3. The remained stress inside the part is basically reduced to zero.

4. The threshold value of hydrogen content for the material after hot sizing is 150 p.p.m.

5. The total thickness of oxidation scale and gas-permeability layer cannot exceed half of the deviation value.

6. There are no changes about the metallographic structure of the material, and there is no sign of overheat or expansion for crystalline grain.

After meeting the requirements above, keep the temperature as low and the time short as possible during the sizing process. As for the pressure, if it makes sure that the part can be pushed and attached into the matrix, then it will be just fine.