Several main reasons and precautions for cracking of aluminum sheet after bending:
Hardness of aluminum sheet
The hardness of the aluminum sheet is too high and it is easy to crack. This requires the selection of high-quality aluminum sheets, mainly depending on the alloy and state of the aluminum sheets. The hardness of the 6 series and 7 series is higher than that of the 1, 3, and 5 series. It needs to be annealed to the O state before it can be bent. There is also the quality of the aluminum sheet.
The thickness of the aluminum sheet
Too thick aluminum sheet is not easy to bend, we understand it as soon as we think about it, and try to use thinner aluminum sheet.
The distance of bending R angle
The larger the bending R angle, the higher the success rate, so try to increase the bending R angle as much as possible.
Aluminum sheet texture direction
The bending direction should be perpendicular to the grain direction of the aluminum sheet, not parallel
For aluminum sheet parts that require drawing, it is best to be bent and then stretched when the process permits, otherwise the probability of bending and cracking will be increased.
First of all, the status is the most important
The state is divided into full hard, semi-hard, and soft state (usually the soft state is called O state), the full-hard bending effect is basically not good (the aluminum sheet state is H18, H19, H38, etc. are all hard), and the semi-hard state Almost all aluminum sheets can be bent (H24 is also semi-rigid). Bending in the O state is definitely no problem, but because it is too soft, basically it is less bending in this state.
The second is that you have to choose pure aluminum or alloy aluminum
The hardness of pure aluminum is not very high. You can use 1100, 1050, 1060, etc., it is recommended to use 1100 H26 alloy aluminum with a better hardness, and you can use semi-hard conditions such as 3003, 3005, 5052.
It is recommended that the sample be determined for specific conditions. If 6061, 2024, 7075 are used because the hardness is too high, especially the T6 state, it should not be bent. Unless it is heated and then bent, the difference between a good quality aluminum sheet and a poor quality aluminum sheet is If there are differences in oxidation performance, tolerance, surface effect, crystal accuracy and uniform stability, the difference in bending effect alone is not big.