METHOD OF HIGH-TEMPERATURE THERMOMECHANICAL TREATMENT OF (ALPHA+BETA)-TITANIUM ALLOYS Russian patent published in 2017 - IPC C22F1/18 

FIELD: metallurgy.

SUBSTANCE: method of high-temperature thermomechanical treatment of (α+β)-titanium alloy is proposed. The method comprises the first step of heating to a temperature lower than the temperature of polymorphic transformation of the alloy at a rate of 210-400°C/min, deformation at a constant temperature, the first cooling stage with rate of 30-50°C/min, the second heating stage to a temperature lower than the temperature of polymorphic transformation of the alloy by 60-100°C, the second cooling stage and the third heating stage to a temperature lower than the temperature of polymorphic transformation by 470-510°C, followed by a final cooling. Before the first heating stage, preliminary heat treating is carried out in vacuum at a temperature lower than the temperature of polymorphic transformation of the alloy by 250-350°C, the first heating stage is performed to a temperature lower than the temperature of polymorphic transformation of the alloy by 310-350°C, deformation at a constant temperature is carried out with a degree of 5-10%, the second cooling stage is carried out in two stages. In the first stage the alloy is cooled at a rate of 100-120°C/min for 2.5 minutes, in the second stage the alloy is cooled at a rate of 3000-3600°C/min to room temperature, after the third stage of heating the alloy is held at the heating temperature for 5-10 hours.

EFFECT: increased ultimate resistance of the treated alloy up to 1200-1270 MPa, flow point up to 1180-1250 MPa and endurance limit up to 410-450 MPa.

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