At present, the cost of titanium alloy is still too high, which seriously restricts its application.Compared with the cost of steel and aluminum alloy, the cost price of titanium alloy is about 17 times that of steel and 4.5 times that of aluminum alloy.According to the statistical analysis of Boeing company in the United States, among the total cost of aviation titanium alloy materials from raw materials to finished products storage, the cost of titanium sponge raw materials accounts for 46%, and the cost of smelting, processing and forming, heat treatment and inspection accounts for 54%.From the perspective of cost composition, there are three main technological approaches for the development of low-cost preparation and processing technology of titanium alloy: first, to solve the low-cost problem of titanium metal extraction metallurgy, to develop new technology of continuous and efficient extraction metallurgy, to reduce the cost of titanium sponge raw materials;The second is to develop new technology of making titanium alloy with short process and high efficiency, which can greatly reduce the cost of making titanium alloy.The third is to adopt the new technology of near-net forming with high efficiency and low cost, which can greatly improve the utilization rate of titanium alloy materials and then greatly reduce the use cost of titanium alloy.
One. New technology of titanium metal extraction metallurgy
New clean titanium extraction process
This new clean titanium extraction and smelting process USES titanium dioxide and carbon as raw materials to prepare ti-c-o with good electrical conductivity by thermal reduction at a temperature of 1500 ℃, and USES it as anode for electrolysis in the molten salt system at 400-1000 ℃. The carbon and oxygen obtained on the cathode are both lower than that of 5×10-4 metal titanium.
FFC Cambridge process
FFC Cambridge Process is an electrochemical method of reducing solid metals, especially oxides, to purer metals or alloys in a molten salt by placing them in a cathode.FFC Cambridge process is seen as a potential refining method that may in the future replace some existing metal production methods, such as the kroll process, which has long been used to refine titanium.
Two. New technology for efficient preparation of titanium alloy
The development of new technology of efficient preparation of titanium alloy mainly includes four directions, including low-cost titanium alloy design, short-flow melting and rolling technology, optimization and improvement of processing properties of titanium alloy, and optimization and innovation technology of titanium alloy preparation and processing.Specific examples are as follows: low-cost titanium alloy manufacturing technology USES Fe, Si, Al, Sn (Cu, Cr, Mn) +O, N, H and other low-cost elements instead of V, Mo, Nb, Ta and other expensive elements to reduce the problem of raw materials.Nanjing university of technology of titanium alloy continuous casting and rolling (CC - HR) new technology of short process a titanium and titanium alloy rolling technology and equipment, low cost in the argon gas protection or inert gas atmosphere, using more than 65 kw plasma gun as a heat source, through the induction furnace, rolling units, idler pulley component implementation of titanium and titanium alloy round, flat ingot casting of continuous casting and continuous rolling, decrease the cost of titanium alloy processing more than about 30%.The titanium and titanium alloy produced has uniform composition, no segregation and no metallurgical quality problem.
Third, improve the utilization rate of titanium materials
By using powder metallurgy near net forming technology and additive manufacturing technology, the high utilization rate of titanium alloy materials was realized.
Powder metallurgy near net forming technology
In order to reduce the cost of titanium and titanium alloy products, foreign countries have developed non-cutting, less cutting near net forming process, and powder metallurgy technology is one of the near net forming process.The material utilization ratio of general forgings is only 10% ~ 15%, and that of general castings is 45%.At present, the main powder metallurgy near net forming technologies at home and abroad are shown in the above table.At present, additive manufacturing technology is applied in the processing of titanium alloy parts, including laser selective melting forming, electron beam fuse forming, laser stereoscopic forming and electron beam selective melting forming.With the progress of science and technology, the application scope of titanium alloy materials will not be limited to aerospace, national defense and medical and health, and titanium alloy 3D printing technology will continue to improve and develop.In the 17th session of the national academic exchange conference of titanium and titanium alloy, professor of nanjing university of technology institute of materials/Chang Hui, vice President of the professor said: "if cost reduces about 50% titanium alloy, titanium alloy dosage will have made very great increase, especially in the field of Marine engineering and weapon equipment, of course in the field of civil consumption will also get a boost.It is estimated that the consumption will reach 300,000 to 600,000 tons/year, which will be 5 to 10 times higher than the current consumption of 60,000 tons/year.By then, China's titanium industry will have reached a new level."