FOR AN UNABLE QUALITY
To eliminate hydrogen and any impurity from the cast aluminum bath used to manufacture the industrial castings, ASEG GALLONI, together with an experienced customer has created an innovative system that combines an inert gas mixing device with vacuum.
When the aluminum/alloy loaded in the crucible has reached the molten state, two hollow graphite propellers are immersed in the bath, mixing the molten aluminum at a controllable speed and, since they are fitted with small holes, they blow inert gas at the same time. In this way, all the hydrogen and heavy scum present in the bath are made to rise to the surface. Once mixing has been completed the two propellers are extracted and vacuum casting is carried out. Thus scum remains trapped in the sprue which is subsequently cut while the alloy making up the piece is perfectly free of impurities and proposity.
“Our customer, with whom we have developed this system- says Gianluca Galloni, company president- works in the aerospace sector, hence it subjects its products to severe quality tests.
Components achieved with this innovative aluminum casting system have been compared, by X ray spectrometry, with pieces manufactured by standard machines. While castings processed with conventional systems featured porosity and impurities, the ones made with our inert gas vacuum mixing technology were completely free of any flaw”.
ASEG GALLONI has developed a device that supplies castings in aluminum and its alloys, featuring an excellent, superior quality.
By combining a special inert gas mixing system and a vacuum system, the new device eliminates porosities and impurities from casted pieces.
A detail of the mixing system.
Inert gas is blown in the molten metal through two hollow graphite propellers to bring to the surface all the hydrogen and impurities present in the bath.
Gianluca Galloni, president of ASEG GALLONI.
Computerized management of the entire process.
THE INNOVATIVE G10
Designed for industrial operators who require great casting capacity and accuracy of the final product, the G10 is an electronic induction casting machine with vacuum and pressure system for metals and industrial alloys. The system uses a low-frequency generator with proportional power control and computerized management of the entire process.
At the beginning a ‘washing’ sequence in the casting chamber is set with vacuum-blowing alternation of inert gas. Once the washing stage is over, the casting stage can begin, until the casting temperature has been attained. During this stage, the computerized system adjusts heating and emits low frequency impulses to inductively mix the mass. Depending on the set temperature value, frequency and power are adjusted irrespective of the type and amount of metal (or alloy) present in the crucible. The metal (or alloy) is thus poured in the flask and the entire chamber is pressurized (depending on the metal to be cast, it is possible to attain values up to 3 bar), compressing the molten metal in the mould.
The action of the vacuum determines a smooth surface of the manufactured object, the action of pressure gives a dense and compact consistency. The critical issue in the casting of aluminum and other light alloys lies in the presence of hydrogen dissolved in the mass. By stirring and inflating the inert gas (generally nitrogen) on the bottom of the crucible, hydrogen is removed. The formation of bubbles with a small diameter favors hydrogen’s aggregation and determines its rising to the surface to be eliminated this facilitating the surfacing of possible waste present in the mass.
The G10 can be combined with a 12000 cc crucible, for a casting capacity up to 30 kg of aluminium.