In addition to chemical composition, the cast rolling plate quality mainly includes grain size, gas and slag inclusion.
In addition to the proportion of electrolytic aluminum liquid and solid material will affect the internal quality of cast rolling plate, the melt refining is the key. In order to make the gas and slag in molten aluminum float to the surface of molten aluminum for enough time, the gas and slag inclusion in molten aluminum can float to the surface of molten aluminum for enough time, and then remove the slag inclusion.
In the process of powder injection refining, the refining agent is evenly sprayed into the liquid aluminum to ensure the purity of nitrogen. Our company uses self-made nitrogen, the purity can be controlled above 99.9995%.
The on-line degassing unit and CFF filter box is used between the holding furnace and the front box. In the degassing unit, graphite rotor and permeable brick are installed at the bottom of the degassing box, so that the nitrogen can refine the aluminum liquid in the degassing box, and carry out the slag and gas. The on-line grain refiner is Al Ti B wire. The inclusion in liquid aluminum was filtered by ceramic foam filter filtration.
After the on-line treatment system, the hydrogen content in molten aluminum can be controlled within 0.12 ml / (100 Gal), and more than 90% can be filtered out if the slag content is more than 5 μ m, and the grain size of cast rolling plate can be effectively controlled, which provides a good internal quality blank for the production of PS plate base, wire drawing panel, double zero foil and other cast rolling coils.
Cast Rolling Plate Quality Control
The shape of cast rolling plate mainly includes the same plate difference, longitudinal thickness difference and crown.
The shape of cast rolling plate is closely related to the length of casting and rolling zone, roll deflection, rolling force, preset roll gap, cooling water temperature, mill stiffness, bearing clearance and roll crown. In production, in addition to strict control of casting and rolling process parameters and bearing assembly accuracy, it is also necessary to reasonably adjust the roll crown and grinding accuracy.
Generally, the crown of casting roll should be determined according to the grade of aluminum alloy and roll diameter. By adjusting the crown of casting roll, the crown of cast rolling plate can be controlled between 0.2% and 0.8%. The shape is adjusted according to the requirements of subsequent cold rolling, the variation range of crown is controlled within 0.6%, the same plate difference is controlled within 0.03 mm, and the longitudinal thickness difference is controlled within 0.12 mm.