en CN

Graphite rotor use and maintenance matters

June 19, 2023

1、The rotating nozzle is made of high purity graphite. The structure of the nozzle not only considers that bubbles should be dispersed, but also uses the centrifugal force generated by stirring the aluminum alloy melt to make the melt enter the nozzle and evenly mix with the horizontal gas ejection, forming a gas/liquid flow ejection, increasing the contact area and contact time between the bubbles and the aluminum alloy liquid, and improving the effect of gas removal and purification.


2、Before dipping into aluminum liquid, the graphite rotor is preheated for 5 min~10 min at about 100 mm above the liquid level to avoid the impact of rapid cooling on the material; The small series of Qingdao durable high-tech graphite rotor introduces that the rotor must first pass into the gas before immersion; The air supply can be stopped only after the rotor raises the liquid level to prevent the stoma of the rotor nozzle from being blocked.


3、The general service life is required to reach more than one month. Its durability is 3-4 times better than that of non-oxidation resistant rotors. About 700 ℃ can be up to 55-65 days, more than 1000 ℃ can be up to 25-35 days, on the surface of the anti-oxidation protective coating, the service life can be extended to 50-60 days.


4,The main reason for the damage of graphite rotor is high temperature oxidation: graphite is mainly composed of carbon, graphite in more than 600℃ air conditions visible oxidation phenomenon, carbon oxidation reaction products are CO and CO2 gas, can not play a protective role on the rotor; The degassing box can not be sealed, and most of the chamber is not filled with protective gas protection, the oxidation of graphite rotor is inevitable. The result of oxidation is that the shaft diameter of the rotor shaft gradually decreases until it is broken and scrapped.