Cast non-ferrous metals include aluminum alloys, magnesium alloys, copper alloys, zinc alloys, titanium alloys, and bearing alloys. The equipment for smelting and refining non-ferrous metals includes furnaces, online degassing equipment, ceramic foam filtering unit. Crucible furnaces are generally used in small and medium-sized factories.
Cast Non-ferrous Metals
Casting aluminum alloys are divided into four categories: aluminum-silicon, aluminum-copper, pot magnesium, and aluminum-zinc. Among them, the most potable alloys used in aluminum-silicon alloys generally use crucible furnaces or reverberatory furnaces.
Aluminum alloy has a low melting point and good fluidity, but it is easy to get gas during the melting process. Most of the gas in the aluminum liquid is hydrogen (about 80%), and there are quite a lot of oxidation slags such as Al2O3. Therefore, degassing and slag removal are the key to smelting.
In order to avoid metal overheating, the melting time should be shortened as much as possible, and the suction should be reduced. In addition, grain refinement (modification) is also required. Refining agents are often used in production, or refining agents and modifiers are used separately.
The refining agent based on sodium nitrate and graphite is a so-called “non-toxic” refining agent developed in the 1970s. In order to change the microstructure of the aluminum alloy, refine the grains, and improve the mechanical properties, the aluminum alloy needs to be modified, and strontium modifiers are widely used in the production.
There are dozens of purification methods for aluminum alloy melt, which can be summarized into three categories, namely, non-chemical reaction degassing, chemical reaction degassing, and mixed degassing. Non-chemical reaction degassing includes blowing inert gas, vacuum treatment, filtration, gas electromigration, and ultrasonic treatment. Chemical reaction degassing mainly refers to the removal of hydrogen from rare earths. Mixed degassing mainly includes gasification flux, blowing active gas and blowing active flux, etc.