Abstract: Jmatpro and Deform softwares were used to simulate the solid solution and aging process (900 ℃ for 1 h, WQ and 540 ℃ for 4 h, AC) of the “A” type TC4 titanium alloy part. The results show that the cooling rate at the top and the feet of the “A” type part is higher than 10 ℃/s and about 48% martensite is produced. After aging treatment at 540 ℃, no fine acicular α′ martensite exist in the microstructure, which is composed of primary equiaxed α phase and dispersed precipitated phase (aging α phase, aging β phase). The maximum equivalent stress after solid solution is 65.6 MPa, while it is only 35.3 MPa after aging. During solid solution and aging process, the temperature gradient and stress at the bolt hole at the top of the “A” type structural part are the largest, where the deformation is changed as rapidly increasing, stably, rapidly decreasing, increasing, stabilizing and gradually decreasing, with distortion of 0.77 mm after the solid solution and aging process.

Key words: large and complex parts, TC4 titanium alloy, equivalent stress, distortion