Effect of Second Annealing on Properties and Microstructures of Commercial Pure Titanium

The microstructures and mechanical properties of cold rolled commercial pure titanium after second annealing was studied.The results show that:the second annealing has no effect on grain size of the factory state pure titanium belt,but it plays an important role in improving the commercial pure titanium plastic processing performance.Moreover,the number of twins increases with the increasing annealing temperature.When the second annealing temperature is lower than 650℃,the yield stress/tensile strength remains unchange.When the second annealing temperature is higher than 650℃,the yield strength decreases obviously; 710℃×60 min annealing can obviously reduce the yield strength and improve its elongation without changing the tensile strength of pure titanium,the sample exhibits excellent processing performance.