Fabrication of large scale bars of Ti-6Al-4V ELI for aerospace application

This paper researched the production and mechanical properties of large scale Ti-6Al-4V ELI bars. Three times vacuum arc melting were used to fabricate big Ti-6Al-4V ELI ingots. The chemical elements of impurity and aluminum, vanadium were analyzed from the top, middle and bottom of ingot. The chemical elements of cross section also were analyzed. The difference of main and impurity elements are very small. To get the homogeneous mechanical properties was very difficult to fabricate the large scale Ti-6Al-4V ELI bars. A special forging technology was adopted to improve the metallurgy microstructure for large scale bars afterwards. The macro and micro structures become finer and finer from the beginning to the end during forging. The very fine grain and very homogenous microstructure are observed in large scale bars from phi 200mm to phi 650mm.The mechanical properties and the damage tolerance properties indicate that the large scale bars could be used to make the important parts of aircraft.