Aluminum alloy forging is prone to sticking to molds, has poor mobility, and is sensitive to corresponding speed changes. Therefore, higher requirements have been put forward for mold manufacturing, mold smoothness, forging deformation level, and deformation rate of forged aluminum parts. The brightness and precision of aluminum alloy molds in our country have not yet reached the requirements for precision forging, and there are mold misalignment, making it difficult to meet the requirements for dimensional tolerances and complete mass production.
For example, some forged aluminum parts abroad require a die angle of less than 1.29 ° (for aircraft aluminum alloy wheels), while the best die angles in China are above 3 °. At present, there is no forging with a small angle of 1.29 ° that can be consumed, which is mainly related to the smooth technology of forging aluminum, the processing technology of mold surface, and the forging equipment (slow speed press should be selected).
In addition, aluminum alloy forging, many foreign forged aluminum parts have non machined surfaces, and the surface of the forgings is bright and intact, giving people a good impression; On the other hand, domestic forged aluminum parts have many surface defects, polishing, and unevenness, which do not look like intact die forgings and have a great contrast with foreign forgings. This is mainly due to the low level of our entire forging process system, mainly manifested as:
① Inappropriate mold design and processing, low precision, poor smoothness, unsuitable or inaccurate billet size;
② The deformation control of each fire is unreasonable, and the deformation speed is too fast, resulting in defects such as cracks and folds;
③ Uneven appearance, large polishing amount, resulting in cracks or folds, which can easily be carried into the parts and produce adverse results.
