彩涂铝板外表出现瑕疵的原因

1彩涂铝板弯（折）辊不正，如压延机轴承发热，使辊的两端膨胀，结果压出的板材中心厚，两端薄；压延前，板材波动过大，使压延量过大，进而发生弯曲；板材压延时，送料不正确，容易引起弯曲；板厚差大时，容易引起弯曲。

1. The bending (folding) roll is not correct, such as calender bearing heating, so that the two ends of the roll swell, the result of pressing out the plate center thick, two ends thin; before calendering, the plate wave is too large, so that the amount of calendering is too large, and then the bending occurs; when the sheet is calendered, the feeding is not correct, it is easy to cause the bending; when the plate thickness difference is large, it is easy to cause the bending.

2. Bubble on the surface: there is dirt on the uneven surface of ingot, which is not cleaned before charging; after etching and washing, there are traces of etching and washing on the surface of ingot and aluminum plate; if the heating time is too long or the temperature is too high, he surface of ingot will be oxidized; if the temperature is too high, the surface of ingot will be oxidized;
3. Ingot cracking: too much reduction during hot rolling, cracking from ingot end; ingot heating temperature too high or too low.
4. When there are defects such as segregation, slag inclusion, scab and crack on the surface of ingot, milling should be carried out (see milling surface of non-ferrous alloy ingot), which is an important factor to ensure good surface quality of finished products.
5. Hot rolling: the hot rolling of aluminum alloy ingots is to provide billets for cold rolling, or directly produce hot rolled thick plates.
6. The hot rolling process includes pass reduction, rolling temperature, rolling speed and lubrication cooling.