The excellent characteristics of titanium alloy are: small density (4.51g/cm3, 57% of steel), high strength (tensile strength 680-1180Mpa), high hardness (30-40HRC), wide operating temperature range (high heat 600℃, low temperature -253℃), good corrosion resistance, no magnetic, small thermal conductivity, low damping performance.
In recent years, titanium alloy in aerospace, ocean engineering, shipbuilding, automotive, chemical, electronics, medical, electric power and other industries demand is increasing, the broad market demand is gradually accelerating the development of titanium alloy forging process and technology.
This article mainly explains the titanium tube manufacturer of titanium alloy heat treatment types and heat treatment specifications. If there is any improper, please correct.
01, titanium alloy heat treatment types
The common heat treatment methods of titanium alloy are annealing, solution and aging. Annealing is suitable for all kinds of titanium alloy, mainly in order to obtain the best mechanical properties, eliminate stress, improve plasticity and stabilize the structure. Solution and aging treatment are the main means of strengthening titanium alloy.
Stress relief annealing
Annealing temperature is 100-250℃ lower than recrystallization temperature.
The purpose is to eliminate or reduce the internal stress in the process of processing, prevent and reduce deformation.
Complete annealing
Also known as recrystallization annealing
The annealing temperature is close to the recrystallization temperature and β transition point, and recrystallization mainly occurs during the annealing process, and the temperature is higher than the recrystallization temperature of the alloy.
The purpose is to reduce hardness, increase plasticity, stabilize microstructure and improve machining performance.
Double annealing
Including high temperature and low temperature annealing, air cooling after annealing; The high temperature is 20-160℃ below the β transition point, and the low temperature is 300-500℃ below the phase transition point.
The purpose is to improve the stability of the organization and performance.
Isothermal annealing
Special form of double annealing
First heating to beta transition point below 20-160℃, after insulation, transfer to low temperature furnace (600-650℃) insulation, and then out of the oven air cooling to room temperature.
It is suitable for titanium alloy with high content of β-stable elements. It adopts slow cooling to decompose β-phase fully.
The goal is to stabilize the organization.
Solution treatment
α+β two-phase zone transition temperature above, β transition point below 28-83℃ heating, special cases can also be heated above the β transition point, then quenching.
The objective is to obtain a high proportion of metastable β phase with aging enhancement.
Aging treatment
Generally between 425-650℃ heating, aging temperature and aging time can be determined according to the aging hardening curve;
The purpose is to promote the decomposition or precipitation of metastable β phase, so as to improve the alloy strength.