The geometric accuracy deviation of titanium alloy rods is mainly caused by the elastic interaction of the material. The hot forming of titanium alloy rods has high internal and external plasticity, high deformation resistance, and severe rebound, making it difficult to form and low geometric accuracy.
The hot forming of titanium alloy rods greatly reduces the deformation and rebound of the formed parts due to the soft ratio effect of high temperature on the material, but rebound cannot be completely eliminated. For example, the resistance heating drop forming or punch forming of titanium alloy rods. After hot forming, there is still a small amount of rebound in the field parts, and the geometric accuracy does not meet the quality requirements, requiring heavy manual trimming.
TC4 titanium alloy has a series of advantages such as excellent corrosion resistance, low density, high specific strength, good toughness and weldability, and has been successfully applied in sectors such as aerospace, petrochemical, shipbuilding, automotive, and pharmaceutical. During the hot forming process of TC4 titanium alloy, a layer of oxide skin will form on its surface. The color of the oxide skin obtained varies with the hot forming temperature. Among them, when the hot forming temperature is about 600 ℃, the oxide skin appears blue; When the hot forming temperature is about 850 ℃, the oxide skin appears gray to reddish; When the hot forming temperature is 900 ℃, the oxide skin appears gray. As the temperature increases, the difficulty of removing oxide scale gradually increases. The removal of titanium alloy oxide scale at home and abroad mostly adopts a two-step method, that is, first melt alkali washing, and then acid washing; However, the temperature of the molten alkali washing medium is relatively high, reaching approximately 450 ℃, and it is easy to cause α+β and β The premature aging strengthening of titanium alloy semi-finished products poses difficulties for further processing. In addition, cleaning with nitric acid and hydrofluoric acid after hot alkali washing may also lead to hydrogen embrittlement corrosion on the surface of titanium alloys.