There are many types of aluminum alloy fluxes used in the melting of aluminum alloys, which can be divided into two categories: covering agents (fluxes that prevent oxidation, burning, and gas absorption of the melt) and refining agents (fluxes that remove gas and inclusions). Different aluminum alloys use different covering agents and refining agents.

However, any aluminum alloy flux used in the aluminum alloy melting process must meet the following conditions:

      1. The melting point should be lower than the melting temperature of aluminum alloy.

      2. The specific gravity should be smaller than that of aluminum alloy.

      3. Aluminum alloy flux can adsorb and dissolve inclusions in the melt, and can remove gases from the melt.

      4. It should not react chemically with metals and furnace linings. If it reacts with metals, it should only produce inert gases that are insoluble in metals, and aluminum alloy fluxes should not be soluble in molten metals.

      5. Moisture absorption should be low and evaporation pressure should be low.

      6. It should not contain or produce harmful impurities and gases.

      7. It should have appropriate viscosity and fluidity.