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Teach you to play with the operation skills of graphite rotor in graphite products

It is known in industryGraphite rotorIf it is used in the degasser, the main causes of damage are:

One is high-temperature oxidation: visible oxidation of graphite occurs in the air above 600 ℃, and the products of carbon oxidation reaction are CO and CO2 gas, which can not protect the rotor; Generally speaking, the degassing box can not be completely sealed, and most of the box cavities are not filled with protective gas, so the oxidation of graphite rotor is inevitable. As a result of its oxidation, the shaft diameter of the rotor shaft gradually decreases until it is broken and scrapped.

The graphite rotor is immersed in the aluminum liquid in the degassing box by secondary liquid scouring, and generally rotates at the speed of 200R / min ~ 400R / min and strongly agitates the aluminum liquid, which will cause strong scouring and friction to the rotor. In particular, the contact part between the liquid level and the rotor will gradually become thinner, and finally it will be broken and scrapped. Influence of transmission system: the transmission system of the degassing device is unstable, especially the connection with the rotor is not concentric, and the rotor swings during operation. On the one hand, the friction between the rotor and the sealing plug causes damage; On the other hand, increasing the rolling of the liquid surface will aggravate the oxidation and scouring of the rotor and accelerate the loss of the rotor.

So how to reduce these damages? This involves the use and operation skills of the graphite rotor, that is, Xiaobian should take everyone to play with the life of the rotor. Let me tell you through five points:
1. Preheating before use:Graphite rotor of aluminum melting furnaceBefore immersion in molten aluminum, preheat it for 5min ~ 10min at about 100mm above the liquid surface to avoid the impact of quenching on the material; The rotor must be filled with gas before being immersed in liquid; The air supply can only be stopped after the rotor raises the liquid level to prevent the air hole of the rotor nozzle from being blocked.

2. Isolation of air: nitrogen or argon is introduced into the purification box to ensure positive pressure in the box and isolate external air to prevent oxidation of graphite rotor.

3. Rotor immersion depth: the graphite rotor is immersed into the aluminum melt at a reasonable depth, so that the strengthening sleeve is exposed to the aluminum liquid surface by about 80mm and immersed below the liquid surface by about 60mm, which can effectively increase the rotor's anti-oxidation loss and erosion wear time.

4. Stable transmission system: graphite rotor and transmission system are connected by connecting rod (pipe). Deformation of connecting rod under high temperature for a long time or looseness of relevant parts of transmission equipment will affect the rotor's alignment and operation stability, which is easy to causeGraphite rotorBreakage or collision may cause damage.

5. Purity of argon or nitrogen: if the argon or nitrogen gas flowing into the aluminum melt is impure due to leakage of pipes, joints and other components, the upper part of the rotor will be seriously oxidized, and even several rotor air holes at the lower part will be oxidized, which will greatly shorten the service life of the rotor.

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