Difficulty Analysis Of Hot Forming Of Titanium Alloy Bar

      The geometric accuracy deviation of titanium alloy bar is mainly caused by the elastic complex after the hot forming, the geometric precision does not meet the quality requirements, must carry on the heavy manual dressing.

      TC4 titanium alloy has a series of advantages, such as excellent corrosion resistance, low density, high specific strength, good toughness and weldability, etc. It has been successfully applied in aerospace, petrochemical, shipbuilding, automobile and pharmaceutical sectors. TC4 titanium alloy will form a layer of oxide skin on its surface during the thermal forming process, and the color of oxide skin will be different due to the different thermal forming temperature. When the temperature of hot forming is about 600℃, the oxide skin is blue. When the temperature of hot forming was about 850℃, the oxide skin was gray and reddish. But when the hot forming temperature is 900℃, the oxide skin is gray. With the increase of temperature, the difficulty of skin removal increases gradually. At home and abroad, the removal of titanium alloy oxide skin mostly adopts the two-step method, namely melting alkaline washing, then pickling; However, the temperature of molten alkali washing medium is higher, which can reach about 450℃, and it is easy to cause premature aging enhancement of αplusβandβtitanium alloy semi-products, which brings difficulties to further processing. In addition, hot alkaline cleaning followed by nitric acid and hydrofluoric acid cleaning may also lead to hydrogen embrittlement corrosion on the surface of titanium alloy.