How to anneal the cold rolled titanium alloy sheet?

The tear fire conditions should be set according to the processing method and application of the product. The annealed structure is uniform equiaxed structure. Because titanium is easy to be oxidized, an oxide film will be formed in an atmosphere containing trace oxygen at high temperature, and there will be back fire color. Therefore, the annealing of cold-rolled titanium coil should be carried out in a vacuum annealing furnace. According to the application, it is sometimes carried out in the atmospheric annealing furnace, and then the pickling treatment of alkali molten salt is carried out to remove the surface oxide scale.

Before vacuum annealing, the cold rolled coil must be cleaned to completely remove the grease such as rolling oil. Generally, it is degreased with alkali washing. The cleaned cold rolled coil is heated after vacuum exhaust in the vacuum annealing furnace. 

The temperature rise shall be carried out in stages to alleviate the temperature difference between the inside and outside of the coil. After vacuum exhaust for some time, it is replaced with helium and stirred with a forced fan to produce convective heat conduction and uniform temperature. Vacuum exhaust shall be maintained at 400 ~ 500 ℃ to obtain a cleaner surface. The annealing temperature is 600 ~ 650 ℃ and the holding time is 5 ~ 10h. Plus the heating time and cooling time, the treatment time of one furnace is about 10 ~ 50h. The atmospheric annealing temperature is 700 ~ 800 ℃, and the holding time is short. The hanging chain type annealing furnace can produce coils with good flatness and reduce the orthopedic load of finishing process.

After atmospheric annealing, remove phosphorus with alkali molten salt (about 500 ℃), and then pickling. The final annealed materials shall be leveled or straightened as required, and then cut edges, strips and plates. They shall leave the factory after surface quality inspection.