The realization of the graphitization process
The graphitization of carbon material is carried out at a high temperature of 2300-3000 °C, so it can only be realized by electric heating in the industry, that is, the current directly passes through the heated calcined product, and the calcined product charged into the furnace is generated by the electric current at a high temperature. The conductor is again an object that is heated to a high temperature.
Furnaces currently widely used include Acheson graphitization furnaces and internal heat cascade (LWG) furnaces. The former has a large output, a large temperature difference, and a high power consumption. The latter has a short heating time, low power consumption, uniform electrical resistivity, and is not suitable for fitting.
The control of the graphitization process is controlled by measuring the electric power curve that is suitable for the temperature rise condition. The power supply time is 50-80 hours for the Acheson furnace and 9-15 hours for the LWG furnace.
The power consumption of graphitization is very large, generally 3200-4800KWh, and the process cost accounts for about 20-35% of the total production cost.
Inspection of graphitized products: appearance tapping, resistivity test
Machining: The purpose of mechanical machining of carbon graphite materials is to achieve the required size, shape, precision, etc. by cutting to make the electrode body and joints in accordance with the requirements of use.
Graphite electrode processing is divided into two independent processing processes: electrode body and joint.
The body processing includes three steps of boring and rough flat end face, outer circle and flat end face and milling thread. The processing of conical joint can be divided into 6 processes: cutting, flat end face, car cone face, milling thread, drilling bolt And slotting.
Connection of electrode joints: conical joint connection (three buckles and one buckle), cylindrical joint connection, bump connection (male and female connection)
Control of machining accuracy: thread taper deviation, thread pitch, joint (hole) large diameter deviation, joint hole coaxiality, joint hole verticality, electrode end face flatness, joint four-point deviation. Check with special ring gauges and plate gauges.
Inspection of finished electrodes: accuracy, weight, length, diameter, bulk density, resistivity, pre-assembly tolerance, etc.