Several main causes and precautions for cracking of metal aluminum sheet after bending:
1. Hardness of metal aluminum sheet
Aluminum plates are too hard and easy to crack. This requires the selection of high-quality aluminum plates, mainly depending on the aluminum plate alloy and state. The hardness of series 6 and 7 is higher than that of series 1, 3 and 5. It is necessary to anneal to o state before bending. There is also the quality of aluminum plates.
2. Thickness of metal aluminum sheet
A thick aluminum plate is not easy to bend. We understand it as soon as we think about it, and try to use a thinner aluminum plate.
3. Distance of bend R angle
The larger the bending R angle, the higher the success rate. Therefore, try to increase the bending R angle as much as possible.
4. Grain direction of metal aluminum sheet
The bending direction shall be perpendicular to the grain direction of the aluminum plate and shall not be parallel.
For aluminum sheet parts requiring wire drawing, if the process allows, it is best to draw after bending, otherwise the probability of bending cracking will be added.
First, state is the most important
The states are divided into full hard, semi hard and soft states (normally soft state is called o state). The bending effect of full hard is basically not good (aluminum plates in h18, H19 and h38 are all hard), and aluminum plates in semi hard state can be basically bent (H24 is semi hard). The o-state bending is definitely no problem, but because it is too soft, it is essentially less to use this state for bending.
The second is whether you want to choose pure aluminum or alloy aluminum.
The hardness of pure aluminum is not very high. It is OK to use 1100, 1050, 1060, etc. it is recommended to use 1100 H26 alloy aluminum with better hardness. It is OK to use 3003, 3005, 5052 and other semi-hard states.
It is recommended to determine the sample again. If 6061, 2024 and 7075 are used, they should not be bent due to their high hardness, particularly in T6 state. Unless they are heated and folded again, the difference between good quality aluminum plate and poor quality aluminum plate is that there are differences in oxidation performance, tolerance, surface effect, crystal accuracy and uniform stability, and the bending effect alone is not very distinct.