Melting III:

        Once the final scrOnce enough scrap has been melted to accommodate the second charge, the charging process is repeated. Once the final scrap charge is melted, the furnace sidewalls are exposed to intense radiation from the arc. As a result, the voltage must be reduced. Alternatively, creation of a foamy slag will allow the arc to be buried and will protect the furnace shell. In addition, a greater amount of energy will be retained in the slag and is transferred to the bath resulting in greater energy efficiency.

ap charge is fully melted, flat bath conditions are reached. At this point, a bath temperature and sample will be taken. The analysis of the bath chemistry will allow the melter to determine the amount of oxygen to be blown during refining. At this point, the melter can also start to arrange for the bulk tap alloy additions to be made. These quantities are finalized after the refining period.

        Graphite electrodes are composed of a mixture of finely divided, calcined petroleum coke mixed with about 30% coal tar pitch as a binder, plus proprietary additives unique to each manufacturer. This mixture is extruded at approximately 220 F, the softening temperature of pitch, to form a cylindrical rod known as a "green electrode". The green electrode is now given a controlled bake in a reducing atmosphere at temperatures as high 1800 F and again impregnated with pitch to increase its strength and density and lower the electrical resistivity. The electrodes are now ready to be graphitized, i.e. converting the amorphous carbon into crystalline graphite. This is accomplished by passing an electric current through them and heating them to as much as 5000 F. The graphitizing consumes as much as 3000-5000kWH/ton of electrode. The final product is strong, dense,and has a low electrical resistivity. Lastly the electrode is machined to its final shape. Into each end of the electrode is a recess in which threads are machined. These are used to accept a threaded nipple manufactured in the same way so the electrode column can be lengthened as it is consumed.

         Operating instruction:

        1.Special hoist tools should be used to hoist the graphite electrode.

        2. The graphite electrode must be kept away from moisture.

        3. Before making connection, the user has to make sure that the socket and the nipple thread remain intact.

        4. The nipple and socket threads should be blown with compressed air.

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