ARJ21 aircraft is basically built by Aluminum Alloy, the quality of aluminum parts more than 75% aircraft net mass, Aluminum Alloy commonly used almost all used, but some more, some less, no matter is the deformation of Aluminum Alloy, or Aluminum Alloy alloy casting, almost all lines are used. The skin plate is forty or fifty kg, small G rivets, but the quantity is very many, up to four a. The number of parts of the ARJ21 airliner is millions, but the fastener is the largest, and the oldest place in the fastener is the old rivet. Rivets may have come out for thousands of years, and they have been used on airplanes for 112 years.
In the ARJ21 regional jet main structure in aluminum is the most used 2XXX and 7xxx alloy, and the alloy is a new generation of manufacturing aluminum used for the prototype of evidence is provided by Alcoa Corp, over a great distance from the west coast of the US across the ocean to Chinese, plates from Iowa (Iowa) Davenport rolling plant (Davenport Works), extrusion and Forging Factory (Lafayette Works) is the Lafayette production, there are also some extrusions from South Korea's long Aluminum Inc, it is a Alcoa Corp in South Korea owned aluminum extrusion company. 2XXX series and 7xxx series alloy accounted for 98% of the total amount of aluminum in the main structure of ARJ21. The prototype machine has not been manufactured with Chinese aluminum products. It is to obtain airworthiness certificate, not to say that Chinese 1kg can not be manufactured. With the airworthiness certificate obtained, the amount of domestic aluminum will be increased year by year.
The deformation of Aluminum Alloy 2524-T3 ARJ21 regional jet for the total amount of sheet, 60%; followed by 7xxx alloy 7050, 7150, 7055, which accounted for about 35% of all applications in T77, T7 said after the solution treatment after aging treatment, the strength of the material although it can reach the maximum a little lower, but the resistance to stress corrosion cracking and intergranular corrosion ability is greatly enhanced.
Full use of 2524-T3 alloy for skin
2524-T3 alloy is really a very cattle 2XXX alloy, ARJ21-700 feederliner all the skin it all, all are made of the pre stretched plate, including the fuselage fuselage skin, fuselage skin, wings, wing and fuselage skin, skin flap, skin butt, sub wing skin flap tail skin, skin, skin, elevator tail rudder and aileron, adjust skin skin and adjustment film, slat skin, elevator tab. The 2524 alloy was born in 1995, and was registered in the same year in the American aluminium Association, while its grandfather "grandfather" 2024 alloy was born in 1934. 2024 alloy 2524 alloy is the sixth generation of the family, in the main components (Cu, Mg, Mn) the content of roughly equal, such as 2024 alloy containing 3.8% 4.9%Cu, while the 2524 alloy was 4% 4.5%Cu; the content of magnesium alloy 2024 is 1.2% - 1.8%, 1.2% - 1.6% and 2524 alloy containing Mg 2024 alloy; with 0.30% 0.9%Mn, while the content of alloy 2524 was 0.45% 0.7%Mn, thus, the alloy 2024 main alloying elements content range than the 2524 alloy and 2524 alloy is loosened, the production difficulty slightly larger.
But the impurity content of 2524 alloy less than 2024 alloy, is a very clean alloy, its impurities Si, Fe, Cr contents were 0.06%, 0.12%, 0.05%, 12%, 2024 respectively, only 24%, 50% alloy, the content of other impurities also fell sharply, and the impurity phase the number is much less, the conventional mechanical properties of the alloy and 2024 alloy, but its fracture toughness and resistance to stress corrosion cracking, fatigue crack propagation resistance than alloy 2024 is strong, but also more resistant to damage tolerance, so its comprehensive performance better than the 2024 alloy, it is a better generation. Parts made with it are more durable, longer maintenance, lower maintenance costs, and safer aircraft.
T3 said sheet after solution treatment after stretching, and then aging treatment (after natural aging) to the user, the user is used for processing parts, because the tension before the user processing parts, it is known as the pre tension, tensile permanent deformation is 1.5% - 3%. The memory sheet after quenching with huge internal stress, surface compressive stresses, internal tensile stress, if not eliminate them, the user using the processing parts will deform into scrap, pre stretching is to eliminate the quenching residual stress, easy to machining workpiece smoothly. The pre stretched aluminum alloy plate is called pre stretched plate, which is used to make aircraft skin, and it is a kind of high-tech product. In the Pre Stretch drawing machine, Chinese can produce pre stretched plate enterprises in Northeast Light Alloy Co. Ltd., Southwest Aluminum (Group) Co., Ltd., Nanshan light alloy company, Aleris International (Zhenjiang) Co., Ltd. 7.
The ARJ21 aircraft parts made of 2024 type alloy are: the wing lower plate with 2524-3511 alloy processing, the wing beam web processed with 2324-T39 alloy. Wing beam manufacturing of 2026-T3511 alloy for the lower edge of the head, the 2026 alloy is registered in 1999 in the United States Aluminum Association Inc in America with a Al-Cu-Mg alloy, its Cu, Mg and Mn content than the 2524 alloy is lower, but the difference is not too large, the content difference between 0.05% - 0.25 and it contains%Zr, Si impurities Fe, Cr, Zn, Ti is lower than the full 2524 alloy, so its comprehensive performance of 2524 alloy is better than T3511, said after the solution treatment after extrusion tensile, tensile permanent deformation of 1%