Titanium Alloy Die Forging Process: Perfect Transformation From Billet To Two-phas

Titanium alloy die forging processTitanium alloy, as a kind of lightweight, high-strength and excellent corrosion-resistant material, has a wide range of applications in aviation, medical, chemical and other fields. Die forging process is a key link in titanium alloy processing, and its quality directly affects the performance of the final product.
This paper will focus on the seven elements of titanium alloy die forging process: billet preparation, heating, lubrication, forging, cleaning, mold design and two-phase titanium alloy forging for a detailed discussion.
First, billet preparation of titanium alloy billets in the die forging must be carefully prepared. The surface of the billet should be roughly machined or roughly ground to ensure that the surface is flat and free of obvious defects and impurities. Bars are usually processed by turning or centerless grinding. Billet cutting is recommended to be carried out with a band saw machine in order to avoid the heat affected zone and oxidation that may result from undercutting by gas cutting.
Second, heating in the heating process, first of all, to remove the slag and oxidized skin on the bottom of the furnace to ensure a clean environment in the furnace. Titanium alloy should be heated with oxidizing atmosphere to slow down the saturation process of hydrogen and reduce the oxidation of titanium alloy and gas pollution. At the same time, the heating temperature and time should be strictly controlled to minimize grain growth. The mold should also be preheated to 250-350°C in advance and held for more than 12 hours to reduce the temperature difference between the mold and the titanium alloy.

Third, lubrication of titanium alloy in the forging process fluidity is poor, so the mold should be lubricated before forging. Lubrication can improve the fluidity of titanium alloy and prevent the forging piece from sticking to the mold. Commonly used lubricants include mixtures of colloidal graphite and water or mixtures of graphite and oil-based or water-based.
Fourth, the die forging deformation of forged titanium alloy is generally controlled between 40% and 80%. After the last heating, the whole metal should have uniform deformation and the temperature distribution during deformation should be uniform to prevent deformation at too low a temperature leading to cracking. For two-phase titanium alloys, sufficient deformation is particularly important, because its grain refinement can not be achieved through heat treatment methods, but only through deformation.
V. Cleaning up the surface of titanium alloys after forging will form a brittle oxide layer, which may lead to cracking of the metal under the surface layer during the next forging. Therefore, after each fire die forging, the oxide layer should be removed using methods such as blowing sand method.
Six, mold design titanium alloy forging mold design is different compared with steel forging mold. Titanium alloy forging mold shrinkage is small, usually with steel forging mold shrinkage ratio of 1:1.87. In the use of the same depth and the same complexity of the mold, forging titanium alloy molds than forging steel molds to be 50% thicker. In addition, the radius of the round corner of the mold should be larger, the surface finish of the die chamber requires higher.
Seven, two-phase titanium alloy forging in the full-phase region of the forging of two-phase titanium alloy, can improve the forging performance of titanium alloy at high temperatures or to improve the notch toughness of forgings. In order to obtain a high comprehensive performance of forgings, the microstructure of the alloy after forging should be controlled within a certain range. The content of isometric phase should be controlled between 15% and 30%, too much will lead to a reduction in notch toughness, and too little will reduce the elongation. If the phase content in the forging is too much, it can be restored by heat treatment to restore its performance.
To summarize, the titanium alloy die forging process is a complex and delicate process involving several key elements. By carefully controlling each link, the quality and performance of titanium alloy forgings can be ensured to be optimized.