Influence of Vacuum Stress Relieving Annealing on Residual Stress of TC21 Titanium Alloy
The residual stress of TC21 titanium alloy was measured at the temperatures of vacuum stress relieving annealing ranging from 500 ℃ to 650 ℃ with an interval of 50 ℃,the time of 2 h and 4 h by blind-hole method.The results show that the residual stress obviously decreases with the increase of annealing temperatures and time.After the heat treatment of 600 ℃× 2 h/ AC,the residual stress decreases 80%,reaches to about 34 MPa,which coincide with the result of microstructure analysis.Thus the optimalized heat treatment process is 600 ℃× 2 h/AC for TC21 titanium alloy.