The geometric accuracy deviation of the titanium alloy rod is mainly caused by the elastic recovery of the material. The titanium alloy rod is hot formed, has large deformation resistance and serious rebound, so the forming is difficult and the geometric precision is low.
The hot forming of titanium alloy rods greatly reduces the distortion and springback of the formed parts due to the softening effect of the high temperature on the material, but the rebound cannot be completely eliminated. For example, the resistance of a titanium alloy rod is heated by drop forming or offset forming. After the parts are thermoformed, there is still a small amount of rebound, the geometric accuracy is not up to the quality requirements, and heavy manual finishing must be carried out.
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 aerospace, petrochemical, shipbuilding, automotive and pharmaceutical sectors. In the thermoforming process, TC4 titanium alloy will form a scale on the surface, and the thermoforming temperature will be different, and the color of the obtained scale will be different.
At home and abroad, the removal of titanium oxide scale is mostly carried out by a two-step method, that is, first washing with molten alkali and then pickling; however, the temperature of the molten alkali washing medium is relatively high, about 450 ° C, and it is easy to cause semi-finished products of α + β and β titanium alloy. The premature aging strengthening has brought difficulties to further processing. In addition, washing with nitric acid and hydrofluoric acid after hot alkaline washing may also cause hydrogen embrittlement corrosion on the surface of titanium alloy.