What are the heat treatment methods for tungsten and its alloys?
Tungsten and its alloys have high hardness, extremely fast work hardening speed, and extremely high additional stress, so heat treatment is necessary. There are several methods.
1. Stress relief annealing
Tungsten has a high room temperature hardness, but the hardness decreases rapidly as the temperature increases. In order to be processed at a higher temperature without recrystallization, the stress relief annealing method can be used.
2. Recrystallization annealing
In the billeting stage of tungsten and its alloys, recrystallization annealing is often used in order to reduce or eliminate the inhomogeneity of the structure.
3. Deformation heat treatment
The solubility of carbides in precipitation-strengthened tungsten alloys in the matrix increases with increasing temperature. Therefore, thermomechanical heat treatment can be used to dissolve the carbides during early processing, and then complete the final processing at a practically feasible low temperature in order to induce Any dissolved carbide is precipitated as fine particles as possible, and the fine subcrystalline structure is introduced as much as possible by cold working.
