In order to cooperate with the cooling and increasing speed of casting and rolling, based on the increase of the nozzle roll gap, the flow pattern of the nozzle must be improved to make the flow field, temperature field and concentration field in the tip cavity uniform.
Due to the cooling and increasing speed of casting and rolling, it is bound to increase the flow of molten aluminum in the casting nozzle per unit time. Under normal circumstances, the height of the liquid level in the front box must be increased to ensure the liquid supply. However, due to the existence of a certain gap between the casting nozzle and the roll, the aluminum melt can be prevented from penetrating into the gap between the nozzle and roll under the action of the surface tension of the gap, so that the casting can be carried out. Under certain conditions, the surface tension of aluminum melt is certain. Therefore, the pressure of the aluminum melt in the gap is limited. Especially as the gap between the nozzle rollers increases, the pressure it bears decreases.
In order to improve the surface quality of the cast-rolled strip, the nozzle roll gap is increased. Simply increasing the liquid level to ensure the full flow of the melt will cause the nozzle roll gap to be oxidized and folded due to the pressure of the melt, and it is undesirable to return to aluminum.
In order to increase the flow of molten aluminum in the casting nozzle in a single time, by optimizing the flow method of the casting and rolling nozzle, the distance between the side stops is increased, so that the metal flow at the two ends far away from the outlet is increased, and the casting nozzle is strengthened. The side aluminum liquid is supplied to increase the temperature of the side metal.
Reduce the distance between the intermediate blocks to slow down the flow of the intermediate metal and reduce the temperature appropriately. And increase the supply of molten aluminum in the stage distribution, ensuring that the liquid aluminum is more quickly and evenly distributed in the mouth cavity under the condition of a certain front box liquid level, so that the metal temperature of the entire cross section is uniform and improves The pressure uniformity and temperature uniformity of the fluid in the casting nozzle cavity are improved, so as to improve the flow field, temperature field, and concentration field of the casting tip cavity, and reduce the uneven distribution of the temperature field and pressure field in the casting nozzle cavity. Internal and surface quality defects of the rolled coil.