关键词: TC4钛合金, 螺栓, 热处理, 滚压, 螺纹缺陷

Abstract: Due to the high strength and poor plasticity of TC4 titanium alloy, defects such as cracks, folds and shear stress lines at the thread root often occur during thread rolling of TC4 titanium alloy bolts. By adjusting heat treatment process parameters (solution treatment temperature, aging temperature, aging holding time) and rolling process parameters (feeding time, spindle speed, pressure holding time), the effects of heat treatment and rolling processes on the thread defects of the TC4 titanium alloy bolts were investigated. The results show that as the solution treatment temperature decreases or the aging temperature increases, the shear strength of the material decreases, the depth of thread tip defects reduces, and there are no thread root defects. With the increase of aging time, the shear strength of the material changes slightly, the depth of thread tip defects shows no significant difference, and there is no impact on thread root defects. The feed time, spindle speed and pressure holding time during thread rolling are reflected in the contact friction time between the thread rolling die and the workpiece. The longer the friction time, the more serious the thread defects.

Key words: TC4 titanium alloy, bolt, heat treatment, rolling, thread defects