Aluminum Degassing Graphite Rotors for Aluminum & Aluminum Alloy Smelting

High mechanical strength and good thermal shock resistance.
Good chemical stability, high temperature resistance and corrosion resistance.
No wettability to molten aluminum.
Do not chemically react with aluminum.

Various kinds of graphite rotors for aluminum degassing

Description

Aluminum degassing graphite rotor is a part of aluminum alloy smelting equipment, which can help remove hydrogen and oxidation residues. Aluminum degassing is a process used in the manufacturing of aluminum alloy castings. During the aluminum and aluminum alloy smelting process, hydrogen generated by chemical reaction with water vapor diffuses into the molten aluminum, causing internal structural defects in aluminum products. To avoid this defect, most aluminum plants use dissolved gas flotation to purify the molten aluminum by injecting inert gases such as nitrogen and argon into the molten aluminum. As inert gas diffuses and rises, hydrogen is brought to the surface of the molten aluminum.

The aluminum degassing graphite rotor forms bubbles on the contact surface between the molten aluminum and inert gas, and increases the gas-liquid contact area, thereby accelerating the diffusion and removal of hydrogen. At the same time, the aluminum degassing graphite rotor can also adsorb and remove oxidization residues in the molten aluminum, and improve the quality and performance of the aluminum alloy.

Features

High mechanical strength, low coefficient of thermal expansion and good thermal shock resistance.
Good chemical stability, and excellent resistant to acids, bases and organic solvents.
No wettability to molten aluminum, and do not chemically react with aluminum.

Specifications

Table 1: Specifications of Aluminum Degassing Graphite Rotor
Grade	Density (g/cm³)	Particle Size	Specific Resistance (μΩ.m)	Porosity	Shore Hardness	Compressive Strength (MPa)	Flexural Strength (MPa)	CTE (× 10^-6 °C^-1)
GE-1	1.72	0.8 / 2 mm	7.5	–	–	35	14	2.4
GE-2	1.60	0.8 / 2 mm	9.5	–	–	25	10	2.9
MD-1 (Molded)	1.78	25 μm	12	20%	48	80	40	5
IS-3 (Isostatic)	1.85	10 μm	12	13%	48	85	46	4.3
Notes: 1 MPa = 10.2 kgf/cm²; 1 W/m.k = 0.86 ^kcal/cm.h.°C These properties are typical values and not guaranteed.

Special Treatment

Impregnation anti-oxidation treatment. To extend the service life of the aluminum degassing graphite rotor shaft, we fill the pores of the graphite material with exclusive technology and nano-antioxidants, and cover the surface of the graphite rotor shaft to improve its heat resistance and anti-oxidation performance.
Coating anti-oxidation treatment. Except for the threads, exclusive coating materials are applied to the impregnated anti-oxidation graphite rotor and shaft. The coating material does not penetrate into the aluminum, but adheres well to the graphite material. Due to its heat resistance, anti-oxidation, corrosion resistance, and abrasion resistance, the service life of the aluminum degassing graphite rotor and shaft is greatly extended after further coating treatment.
Local reinforcement. Based on the actual application of the user, we can strengthen the most vulnerable parts at the lowest cost to obtain the longest service life of the aluminum degassing graphite rotor and shaft..

Working Principle

The working principle of the aluminum degassing graphite rotor is that the transmission system drives the graphite rotor to rotate, and inert gas (argon or nitrogen) is blown into the aluminum molten liquid through the rotor rod and nozzle. The high-speed rotating graphite rotor disperses the argon or nitrogen entering the aluminum molten liquid into many small bubbles, dispersed in the molten metal. When the bubbles contact each other, the bubbles in the molten liquid absorb hydrogen and oxidization impurities by relying on the gas pressure difference and surface adsorption principle, and are brought out of the molten liquid surface with the rise of the bubbles, thereby purifying the molten liquid.