NUST MISIS scientists have developed a model-free technology to manufacture aircraft parts from titanium alloys for the Russian aircraft industry. The new technology, planned to be used in the manufacturing of parts for the MC-21, is noticeably cheaper, more environmentally safe, and allows for more precise components than current techniques.
Specialists from the Engineering Center “Foundry Technologies and Materials” at NUST MISIS have abandoned the classic casting technology of titanium alloys and suggested a model-free technology.
“NUST MISIS scientists have developed a unique, import-substituting technology that allows for the use of domestic raw materials and equipment. Professor Vladimir Belov and his research team have presented several developments for the aerospace complex during the past several years. The developments were awarded State Prizes and the highest awards at prestigious international exhibitions. In 2016, their inventions were awarded both the gold medal at the International Exhibition of Inventions—Geneva and the Moscow Government’s prize for young scientists”, said Alevtina Chernikova, Rector of NUST MISIS.
The new technology`s secret is the use of graphite rough materials of a complex configuration produced by milling on machines with numerical control. Graphite barely interacts with the titanium melting process, so the obtained castings are thin-walled, without a contaminated saturated layer which reduces the titanium’s ductility. The traditional technology creates castings with thicker walls, so the products feature a saturated layer which needs to be removed.
The new technology will allow for products made entirely from domestic raw materials (current ceramic forms which are supplied from abroad are used) and more importantly, aircraft parts with greater dimensional accuracy than we currently have. Another advantage of model-free technology is its low cost and environmental safety in comparison with western analogues.
“The main advantage of our technology is that we managed to make a casting which has a wall thickness of only
3-4 mm.There are no similar technologies in the world right now. In the manufacture of castings through other technologies the wall thickness is 10 mm, and the process requires environmentally harmful etching procedures — namely the removal of excess material with chemical acid. A whole line of environmentally harmful production is created for this procedure. Model-free casting doesn’t require etching and casting is much easier, while also reducing the wall thickness. Similarly, the new technology allows us to minimize the cost for the mechanical treatment of products”, said Professor Vladimir Belov, head of the research team, head of the Department of Foundry Technology & Artistic Processing of Materials at NUST MISIS, and the Director of the NUST MISIS Engineering Center of Foundry Technologies and Materials.
This technology is ideal for advanced Russian projects in the aircraft industry, such as the short-medium haul passenger airplane, the MC-21. With the help of this new technology, specialists have already casted details for the PD-14. The detail—a lite-welded construction of the internal intermediate case of the turbine—consists of seven pillars, an inner case, and a rolled ring.
The MC-21 will be able to compete successfully with the Chinese Comac C919, the Boeing-737 MAX, and the Airbus A320neo. The aircraft is planned to be delivered to Malaysia, Egypt and Azerbaijan; companies from Malaysia and Egypt have already signed purchasing agreements, and the signing of an agreement with Azerbaijan will be held in February 2017.
“The improvement of jet-engines is always a way to improve the traction of recoil from one kilogram of aircraft design. The conditions of modern competition are such that those planes that can achieve higher fuel efficiency than its competitors rule the market. Creating intricacies instructures and technologies requires new technological solutions. Nowadays linear technologies in aircraft engine construction get new development and the work done by NUST MISIS in the field of thin-walled titanium casting is undoubtedly relevant and requires further development”, said Alexei Ionov, Deputy Director of the Department of Production Technologies of Engines for Flying Vehicles at the Moscow Aviation Institute.
The developers have spent 3 years on the creation of this technology. Now specialists are continuing to develop the technology—they are looking for a way to make graphite molds reusable. The experimental-industrial testing has already been conducted and work has turned to making a new set of castings for the technology`s integration into aircraft production.