Metal Degassing Equipment mainly processes molten aluminum containing a certain amount of hydrogen and other residues (alkali metals, slag inclusions). It is extremely critical equipment to improve the purity of aluminum melt. Aluminum and its alloys are one of the most severely polluted by inclusions and hydrogen, and their purity will greatly affect the quality of the metal.
The purity of aluminum is mainly determined by dissolved hydrogen and non-metallic inclusions. Hydrogen is the only gas that dissolves in large amounts in the aluminum melt. The solubility of hydrogen in aluminum liquid and solid phases is 0.65ml/100gAl and 0.034ml/ 100gAl, the difference is about 19.1 times.
In addition to the water vapor reaction and the charge, the inclusions in the aluminum melt are mainly formed by the reaction of aluminum and oxygen during the melting process. Therefore, when the metal aluminum is melted into a liquid state, hydrogen and inclusions will inevitably exist. Therefore, the aluminum melt must be degassed and filtered before casting, otherwise, it will cause poor mechanical properties of the aluminum produced, surface defects, pores, and cracks, which restrict the application of high-performance aluminum alloy.
At present, the purification effect of the furnace refining treatment of aluminum alloy melt commonly used in the industry is limited, and the melt is prone to secondary pollution during the flow process, so it is difficult to control the impurities in the melt (hydrogen, alkaline metals, non-metallic inclusions). The ingot cannot meet the usual quality requirements, it must be further purified, which has developed the on-line degassing and filtration purification treatment technology outside the furnace. Compared with the furnace treatment, the purification treatment outside the furnace has a good purification effect, no secondary pollution of the melt, low labor intensity, and no pollution. The combination of continuous casting or continuous casting and rolling can realize continuous and automatic casting production. Online degassing filtration system continues to mature, and has become an important means for the development of the world’s aluminum industry.
Hydrogen is a harmful gas in molten aluminum. Pre-furnace detection of the hydrogen content of molten aluminum is an important process to ensure the quality of castings. Especially when large-capacity furnaces are used for mass production, the use of Metal Degassing Equipment to remove hydrogen and slag becomes indispensable.
If the hydrogen content in the alloy ingot or cast-rolled sheet is too high, it will appear in the aluminum alloy product in the form of hydrogen bubbles because it is too late to escape during the solidification process.
When the alloy slab or cast-rolled coil is rolled to a certain thickness, holes will appear at the place where the hydrogen bubbles appear, which will cause the rolled strip to break and cause the product to be scrapped.