If the aluminum liquid is not purified well, there will be too much hydrogen and inclusions in the aluminum liquid.
The gas will not be discharged smoothly during casting and solidification. The aluminum rod will break when pulled out.
Casting Temperature
During the continuous casting process, the casting temperature is too low, the fluidity of the molten aluminum is relatively poor, the gas in the molten aluminum escapes slowly, and the molten aluminum cannot be fed in time when it solidifies. It is easy to produce shrinkage cavities and porosity in the slab.
Casting Speed
In this case, it is easy to form a liquid cavity that is too deep, and the instability of the liquid level increases, resulting in a short-term liquid level that is too low, and the liquid flow cannot be supplied, resulting in loosening and shrinkage of the shrinking tissue.
The fast casting speed also increases the speed of the crystallization wheel.
In the case of other inconvenient process conditions, the cooling time of the slab is shortened accordingly, and the temperature is slightly higher when it leaves the crystallization wheel, which not only affects the structure of the slab but also the progress of the rolling mill.
The feed temperature is also higher. Under the condition that the cooling condition of the rolling mill remains unchanged, the aluminum rod softens and breaks because the rolling speed of each pass of the rolling mill is accelerated, the cooling temperature is reduced, and the final rolling temperature is increased.
Cooling Intensity
When the aluminum liquid is poured into the copper crystal wheel if the cooling intensity is too high, it is easy to form a cooling gradient before the aluminum liquid solidifies, causing the aluminum liquid close to the copper crystal wheel and the steel strip to cool rapidly and solidify into an aluminum billet shell, and the aluminum liquid that solidifies later in the center will flow toward The shell is replenished, resulting in porosity and shrinkage cavities in the center of the aluminum billet.
Especially when the cooling intensity is too high and the casting temperature is too low at the same time, it is easier to form loose and shrinkage cavities of the aluminum billet, and in serious cases, it may even appear obviously hollow, resulting in broken rods during the rolling process.
The original casting cooling water configuration mode is that the internal cooling starts to spray water when the aluminum liquid reaches crystallization, and the external cooling starts to spray water 250 mm after the aluminum liquid touches the steel strip.
Stop the internal and external cooling 400 mm before the slab is demolded, the cooling water distribution is 2:1, and the internal and external cooling water volume gradually increases.
The main problem with this cooling water configuration mode is that the aluminum liquid is poured into the mold cavity and is strongly cooled and the temperature drops too fast, resulting in insufficient feeding capacity when the aluminum liquid solidifies.
Casting Method
Generally, the casting method of the wheel-belt casting machine is inclined and open casting, that is, the molten aluminum is transported from the small ladle through the inclined nozzle to the crystallization mold cavity formed by the copper crystallization wheel and the steel belt.
Since the drop of the aluminum liquid reaches 200mm, the oxide film is broken and mixed into the aluminum liquid to form inclusions, and the air is mixed into the aluminum liquid to increase the content of the aluminum liquid gas slag. In addition, the casting point is controlled by people, with frequent fluctuations and large deviations.
The aluminum liquid flow tends to be biased to one side, resulting in turbulence and turbulence in the casting cavity to form air pockets and cold shuts.
In the process of horizontal continuous casting of aluminum rods, apart from the purity of the aluminum liquid itself, the reason for the breakage of the aluminum rods is that the casting temperature, casting speed, cooling intensity, and other casting processes do not match, which will cause porosity and shrinkage cavities, and eventually lead to fracture.
Luoyang HTGP is a professional aluminum melting furnace manufacturer, providing aluminum liquid of various outputs as well as professional installation and after-sales services.