After heat treatment of aluminum alloy forgings, due to the high temperature heating, bubbles often appear on the surface of the forgings, the bubbles are very thin, gas escapes when opened in the water, the bubbles are obviously layered, and the inner wall is corrugated and gray-black. combustion products. At the same time, the phenomenon of surface peeling often occurs, which is also due to the rough surface of the die groove, the temperature of the forging deformation process is too high, the degree is too large, the speed is too fast, the die is not lubricated or poorly lubricated, and the aluminum alloy is easy to stick to the die.
The existence of these defects makes a large number of aluminum alloy forgings scrapped due to surface problems. Some of them need to be saved for processing and use through negotiation with users and acceptance of concessions, but they also have adverse effects on enterprises.
From the quality of the surface of aluminum alloy forgings, we can see the technological level and quality management level of an enterprise, and we can see our own shortcomings. In particular, due to the surface quality problem of the forgings, grinding and repairing, the size does not meet the requirements of the drawings, the number of repetitions is many, and the pass rate of one inspection is low, resulting in a waste of manpower and material resources. Some are scrapped in batches because the final size exceeds the tolerance and does not meet the requirements for use. Some aluminum alloy forgings have a pass rate of less than 50%, which is caused by the lack of improvement in our technology level and understanding.
The mechanical properties of aluminum alloy forgings do not meet the requirements of technical standards is also a problem that often occurs in physical and chemical testing, which generally needs to be solved by supplementary aging or repeated heat treatment.
Therefore, heat treatment is very important to improve the microstructure and properties of aluminum alloy forgings. This requires the measurement of the furnace temperature uniformity and accuracy of the heat treatment furnace, and the furnace can be installed after meeting the requirements of use. At the same time, the selection of heating temperature and heating time To be appropriate, the transfer time should be as short as possible. Generally, a heating furnace with a temperature control accuracy of ±3 °C is selected to ensure that a single heat treatment can have good mechanical properties, and repeated heat treatment should be avoided as much as possible to reduce energy consumption and shorten the production cycle.
Aluminum alloy forgings account for a small proportion of the output value of the enterprise, so the quality problems that arise cannot be paid much attention to. In the technical process research, equipment transformation, forging process, and heat treatment process, there is no in-depth systematic analysis and thinking.
In particular, there is a lack of analysis and research on forging cracks, forging coarse grains, surface quality and grinding treatment, machining deformation and stress cracks. These existing problems should be systematically upgraded and improved in terms of mold machining accuracy, lubricant, heating temperature, surface protection and treatment, etc., to improve the quality stability of aluminum forgings, and to better participate in international market competition.