Airway Defects in Continuous Casting and Rolling Process

Airway defects in continuous casting can be divided into mild and severe cases. On the cross-section of the cast rolling plate, there are some micro holes in the cross-section of the cast rolling plate, which are not continuous crystallization, but holes appear in the serious cases. Air passage is a serious defect in the production of plate and foil.

Airway Defects in Continuous Casting

Airway Defects in Continuous Casting Causes

The main reason for the gas generation channel is that the hydrogen content in the melt is too high. At the crystallization front, because the solubility of hydrogen in solid aluminum is very small, the hydrogen content in the melt at the crystallization front is higher. At this time, if the grains are coarse, dendrites develop, and form poor feeding voids, or other inclusions help hydrogen nucleate, hydrogen in the melt will precipitate here and become hydrogen bubbles.

Due to the continuous casting and rolling process, the gas is not easy to enter the solid due to the rolling effect. In the production process, the bubbles constantly accept the supersaturated hydrogen discharged from crystallization and grow up gradually. When the bubbles grow to a certain extent, the supersaturated hydrogen will continuously precipitate into gas channels.

Airway Defects in Continuous Casting Elimination Method

The hydrogen content in the melt was reduced to below 0.15 ml / 100 g Al by strengthening refining. Al-Ti-B grain refiner was used to refine the grains.

The impurities in liquid aluminum can be filtered out by using the filter device to reduce the nucleation particles of hydrogen.

The slag running and outgassing during coil cutting.

AdTech offers fluxes for refining in the furnace, online degassing system and CFF filtering system for molten aluminum purification. The online degassing unit has dual functions: processing and heating. It can remove hydrogen (H) and slag from molten aluminum. Otherwise, they will affect the quality and mechanical properties of the alloy. The online degassing unit has dual functions: processing and heating. The CFF filter system is suitable for filtering the inclusions and small particles in the molten aluminum. It adopts the new technology of high fused silica and has a long life. The filtering equipment replaces the ceramic tube filter equipment and common plate filter equipment. This plate filtering unit can effectively filter the micron impurities.