Aluminum alloy production practice has proved that hydrogen is the only gas that can be dissolved in a large amount in aluminum or aluminum alloy, and the most soluble gas in aluminum alloy. So the aluminum alloy refining is an important step. When smelting aluminum alloy, the refining agent should be added in proportion. The refining agent is generally 0.3% of aluminum alloy. The degassing time is not enough. A seamless steel pipe is used. The scouring agent is sprayed with nitrogen or argon at 20 cm at the bottom of the aluminum liquid. After scouring and spraying, nitrogen or argon is blown for another 15-20 minutes. After scouring, it is sedated for 10-15 minutes, the aluminum slag is stripped off, and poured with a ceramic foam filter.
Various casting nonferrous metals have the characteristics of absorbing gas. The alloy liquid in the process of smelting or heat preservation increases the solubility of the absorbed gas rapidly as the temperature of the alloy increases. Therefore, in addition to correctly controlling the entire smelting and pouring process, the alloy liquid should be kept as low as possible at high temperature to avoid overheating of the alloy liquid. For alloys that are easily absorbed, smelting under the protection of the covering agent should be adopted. Only in this way can air holes and pinholes be avoided.
In order to reduce the oxidation of aluminum alloy, in addition to selecting the appropriate furnace for melting, the holding furnace should be used for heat preservation in the die casting production. Avoid melting and die casting production, reduce stirring as much as possible, keep the liquid oxide film intact, and avoid unnecessary alloy liquid overheating and shorten the time of the alloy in the holding furnace as much as possible.