Abstract:The mechanical properties of TA2 extruded tube were tested by uniaxial tensile test at high temperatures ranging from 700 °C to 850 °C and different strain rates changing from 4×10^-4 s^-1 to 4×10^-1 s^-1. The tube bulging test was carried out at elevated temperatures up to 950 °C to evaluate the formability of TA2 extruded tube for hot metal gas forming (HMGF). The total elongation and the maximum expansion ratio of the tube were obtained. The bursting pressure and fracturing manner were analyzed. The results show that the tensile strength of TA2 tube decreases practically with temperature increasing and strain rate decreasing. Meanwhile, the total elongation is between 142% and 331%. In tube bulging test, special experimental setup was established by the way of induction heating. The bursting pressure decreases from 6.5 MPa to 1.2 MPa as temperature increases. The maximum expansion ratio increases firstly and reaches the maximum value of about 70% at 890 °C, and then decreases. Fracture occurs along hoop direction, axial direction and random direction at different temperatures. The ideal temperature range for TA2 tube forming is from 860 °C to 920 °C in HMGF process.

Key words: TA2 Ti alloy tube; uniaxial tensile test; tube bulging test; hot metal gas forming (HMGF); bursting pressure; maximum expansion ratio (MER)