Aluminum alloy heat treatment replaces the salt furnace with an air circulation electric furnace
The traditional heat treatment is heated by a nitrate salt furnace, which has the disadvantages of serious environmental pollution, large energy consumption and waste, and the air circulation electric furnace has the advantages of quick start-up and good energy-saving effect, and the quenching transfer time is fast and adjustable to meet different aluminum alloy parts. Claim. After the air circulation electric furnace is heated, the solution quenching has no pollution to the cooling medium, which is beneficial to popularize the use of the organic quenching medium, reduce the heat treatment distortion and improve the production efficiency.
The key technology of the air circulation electric furnace is how to ensure the uniformity of the furnace temperature (±3 ~ ± 5 ° C), especially the requirements of the large size furnace, how to meet the furnace temperature uniformity requirements of lower temperature (100 ~ 150 ° C). The second key technology is how to ensure rapid quenching transfer time, and can be adjusted and controlled according to different requirements of parts.
Organic quenching medium
Aluminum alloy quenching medium is usually water or hot water, but for heat treatment deformation or deformation is strict, hot water can not meet the requirements, must use organic quenching medium aqueous solution. The use of an aqueous solution of an organic quenching medium instead of water on an air circulating electric furnace reduces the heat treatment deformation of the aluminum alloy and the correction work time of the sheet metal parts by more than 50%.
Since aluminum alloy materials have been used in aircraft manufacturing, tensile tests or hardness tests have been used to test the heat treatment quality of aluminum alloys. Since the aluminum alloy is heat treated, there may be two different states at one strength (hardness) value, whereas in one state, there may be two different strength (hardness) values. Therefore, it is a backward detection method to control the quality of the aluminum alloy after heat treatment using only hardness or strength, and the quality cannot be completely ensured.
The conductivity detection has the advantages of convenience, quickness, high work efficiency, and is basically not limited by the shape and weight of the object to be inspected, and has no damage to the parts. Since the 1980s, conductivity testing has been widely used in domestic heat treatment state inspection of aluminum alloy materials/parts. In GB/T12966-1991 "Aluminum Alloy Conductivity Eddy Current Test Method" standard, the test method, GJB2894-l997 "Aluminum Alloy Conductivity and Hardness Requirements" is given, and the conductivity and hardness values are specified.