Common heat treatment methods include annealing, solid solution and aging treatment. Annealing is to eliminate internal stress, improve plasticity and microstructure stability, so as to obtain better comprehensive properties. Alpha alloy and usually (alpha + beta) alloy annealing temperature in (alpha + beta) ─ to beta phase transition point below the 120 ~ 200 ℃; The solid solution and aging treatment is to get the martensite 'phase and the metastable phase from the rapid cooling at high temperature, and then the decomposition of these metastable phases in the heat insulation at medium temperature to get the fine dispersion of the second phase particles such as phase or compounds, so as to strengthen the alloy. Usually (alpha + beta) alloy quenching in (alpha + beta) ─ and beta phase transition point below 40 ~ 100 ℃, metastable beta alloy quenching in (alpha + beta) ─ and beta phase transition point above 40 ~ 80 ℃. Aging treatment temperature of 450 ~ 550 ℃.
In conclusion, the heat treatment process of titanium alloy can be summarized as follows:
(1) stress relief annealing: the purpose is to eliminate or reduce the residual stress generated in the processing process. Prevent chemical erosion and reduce deformation in some corrosive environments.
(2) complete annealing: the purpose is to obtain good toughness, improve machining performance, facilitate reprocessing and improve the stability of size and structure.
(3) solid solution treatment and aging: in order to improve its strength, titanium alloy and stable titanium alloy cannot be strengthened heat treatment, only annealing in production. + titanium alloys and metastable alloys containing a small amount of phase can be further strengthened by solid solution treatment and aging.
In addition, in order to meet the special requirements of the workpiece, the industrial use of double annealing, isothermal annealing, heat treatment, deformation heat treatment and other metal heat treatment process.
