In the 1960s, the United States began to research the investment casting technology of titanium alloy, and successively completed the investment ceramic shell, graphite mold machining and HIP hot isostatic pressing technology, which has been widely used. Since 1972, cast titanium alloys have been officially used in aircraft, first used in non-critical static structural parts with small stress, such as engine hood, diaphragm, oil duct, etc. With the improvement of casting performance, titanium alloy investment castings have also been used in some key load-bearing parts, such as the CF6 – 80 engine mounting hanger investment castings developed with Ti – 6Al – 4V titanium alloy, which have undergone long-term service assessment, The operation has been relatively good.
The overall titanium alloy intermediate casing of the CF6 – 80C2 engine in the United States is produced by investment casting, and the overall overall outline dimension is up to φ 1300mm × 368mm。 GE90 engine fan hub manufactured by American PCC company has a diameter of 2000 mm, a minimum wall thickness of 1.0~2.0 mm, and a dimensional tolerance of ± 0.13 mm. PCC also used investment casting to prepare the front part of the combustion chamber of the C – 17 aircraft, with a length of 760 mm and a width of 1.25 mm, replacing 17 components, saving more than 40% of the cost (see Figure 1).
Figure 2 shows a typical titanium alloy casting case with a diameter of 782mm and a mass of 82kg. At present, the rear mounting frame of the Boeing 777 engine, the world’s largest twin-engine wide-body passenger aircraft, uses titanium alloy precision castings, which has achieved a zero breakthrough in the use of titanium alloy investment castings in civil aircraft. In view of the use requirements of high safety and reliability of passenger aircraft, it is of great significance. The titanium alloy brake torque tube manufactured by British Doncaster Company using centrifugal investment casting technology is used for A380 passenger aircraft, which is the first time in Europe to use titanium alloy brake torque tube investment casting to replace the previous forgings.