Heat treatment technology for aviation aluminum alloy
With the development of transportation technology, aluminum alloy is widely used in aviation materials due to its light weight, high strength and convenient processing. The effective application of aluminum alloy reduces the structural weight of aircraft, improves flight performance and increases economic benefits. Therefore, more attention has been paid to aviation aluminum alloy technology.
Air - circulating electric furnace was used instead of nitre furnace in aluminum alloy heat treatment
The traditional heat treatment USES nitre furnace heating, there are serious environmental pollution, energy consumption and waste, and air circulation furnace has the advantages of quick start, good energy saving effect, quenching transfer time is fast and adjustable, to meet the requirements of different aluminum alloy parts. After heated by air circulating electric furnace, solid solution quenching has no pollution to the cooling medium, which is beneficial to popularizing the use of organic quenching medium, reducing heat treatment distortion and improving production efficiency.
The key technology of air circulation furnace is how to ensure the uniformity of furnace temperature (+ / - 3 ~ + / - 5 ℃), especially the large size of the stove, how to meet the low temperature (100 ~ 150 ℃) on furnace temperature uniformity requirements. The second key technology is how to ensure the rapid quenching transfer time, and can be adjusted and controlled according to the different requirements of the parts.
Organic quenching medium
Water or hot water is commonly used as the quenching medium for aluminum alloy, but for the case of large deformation or severe deformation during heat treatment, the hot water cannot meet the requirements, so the aqueous solution of organic quenching medium must be selected. Use organic quenching medium water solution instead of water in the air circulating electric furnace to reduce the heat treatment deformation of aluminum alloy and the correction time of sheet metal parts by more than 50%.
Since aluminum alloy material is used in aircraft manufacturing, tensile test or hardness test has been used to detect the quality of aluminum alloy heat treatment. Since aluminum alloy after heat treatment, in a strength (hardness) value, there may be two different states, on the contrary, in a state, there may be two different strength (hardness) value. Therefore, using only hardness or strength to control the quality of aluminum alloy after heat treatment is a backward detection method, can not completely ensure the quality.
Conductivity detection has the unique advantages of convenience, high efficiency, and basically not limited by the shape, weight and other conditions of the tested parts, and no damage to the parts. Since the 1980s, conductivity detection has been widely used in the heat treatment of aluminum alloy materials/parts in China.