Stress relaxation tests and tensile strength tests for TA15 titanium alloy sheet were carried at elevated
temperatures. The stress relaxation behavior and influence of different factors were discussed. Flow stress rules for hot
deformation of TA15 alloy were obtained. It was concluded that the residual stress falls fast at the first stage, while
slowly at the second stage at 600 to 700℃, and the residual stress approaches a limit after 1 500 seconds. The influence
of temperature on the stress relaxation is obvious, the higher the temperature is, the faster the stress relaxes. Initial
stress, pre-strain, rolling direction have small effect on stress relaxation, and the influence is less with the rise of
temperature. With the temperature increasing the flow stress of TA15 alloy is decreases at 675℃ to 800℃. The flow
stress followe the first class of constitutive equation.