Flux for aluminum refining should be added in proportion. Aluminum concentrate is usually 0.3% of aluminum alloy. Methods a seamless steel pipe was used, which was inserted 20 cm away from the bottom of molten aluminum, and the refining agent was sprayed with nitrogen or argon.
After refining the spray, then blow nitrogen or argon for 15-20 minutes. After refining, let stand for 10-15 minutes, and then remove the aluminum slag.
Various cast nonferrous metals have the characteristics of absorbing gas. In the process of melting or holding, the solubility of absorbed gas increases rapidly with the increase of alloy temperature.
Therefore, in addition to the correct control of the whole melting and casting process, the heat preservation effect of liquid gold at high temperature should be reduced as far as possible to avoid overheating of the alloy liquid.
For the alloy which is easy to attract, holes and pinholes can be avoided by melting under the protection of covering agent.
In order to reduce the oxidation of aluminum alloy, in addition to selecting a suitable melting furnace, the holding furnace should also be used for heat preservation in die casting production.
Do not melt and die-casting products, reduce stirring as much as possible, and keep the oxide film on the liquid surface intact. Avoid unnecessary overheating of alloy liquid and try to shorten the time of alloy in holding furnace.
In the process of die casting, a part of the gas in the pressure chamber can not be discharged from the cavity, but into the molten metal. During the filling process, back pressure will be generated to reduce the flow rate, resulting in cold isolation, insufficient castings, blowholes and loose castings.
In order to eliminate the casting defects caused by this, the mould must be equipped with exhaust groove. The exhaust groove is usually matched with the overflow groove and is arranged at the rear end of the overflow groove. In some cases, the exhaust groove can also be set in the cavity separately.
The higher the melting temperature, the longer the melting time and retention time of aluminum after melting, the more sufficient hydrogen diffusion in molten aluminum, the greater the amount of hydrogen absorbed by molten aluminum, and the greater the probability of occurrence.
The longer the storage time of molten aluminum is, the more gas content in the aluminum alloy increases approximately. Fluxes for aluminum refining can remove gas from molten aluminum. Most aluminum foundries choose Adtech flux for aluminum refining, which has good performance in degassing and removing impurities.