Medical titanium wire The materials for processing and forging are mainly pure titanium and titanium alloys with various compositions. The original state of materials includes titanium bars, ingots, metal powders and liquid metals. The ratio of cross sectional area of metal before deformation to that after deformation is called forging ratio. Correct selection of forging ratio, reasonable heating temperature and holding time, reasonable initial forging temperature and final forging temperature, reasonable deformation amount and deformation speed have a great relationship with improving product quality and reducing cost.
Generally, small and medium-sized forgings use round or square bars as blanks. The grain structure and mechanical properties of the bar are uniform and good, the shape and size are accurate, and the surface quality is good, which is convenient for mass production. As long as the heating temperature and deformation conditions are reasonably controlled, the forging with good performance can be forged without large forging deformation. In aircraft, titanium alloy is mainly used to manufacture main load-bearing components such as girder, landing gear, hub and joint; The titanium alloy on the engine is mainly used to manufacture the adapter ring, turbine fan, compressor disk, blades and other stressed and heated parts.
If conventional forging method is used for processing titanium alloy bar, because the forging temperature range is only about loo ℃, the deformation disturbing force will increase sharply with the temperature drop of billet during forging, and a forging press with large tonnage is required. In order to reduce the forging pressure of titanium bars and segments produced in China, we have to use Danzhong forgery. The result is easy to move the high rib wave in the middle to the edge, which increases the difficulty of filling the high rib.
Therefore, effective technological measures should be taken, such as increasing the preheating temperature of the spreader to reduce the temperature drop; Use glass lubricant to prevent surface contamination and improve metal flow. What is particularly effective is to add the process locating boss. The two fire die forging is used to form the skin. The first fire is used to install the high rib groove in the lower die. The upper and lower dies with locating boss are installed on the upper rafters. The second fire is used to exchange the upper and lower dies. The boss is used for positioning. This greatly reduces the contact time between the metal filling the high rib part and the die wall, slows down the cooling effect of the die, and improves the filling performance of the titanium rod. Thus, on the 25t-m counter hammer, the titanium rod component for "normal" aircraft with a length of 1395mm and a projection area of 0.2 square meters can be successfully forged. After inspection, not only the overall dimension, twist, surface quality and hydrogen content meet the technical requirements, but also the low power is fuzzy convex.
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