1. Product Introduction & the Standard

　　1). The product is a new generation monolithic material for the building of electric furnace bottoms. Simple setting & easy maintenance allow the material to be utilized on un-limited sizes, types & models of furnaces. Its service life is several times even several dozens times higher than brick laid bottoms. In recent years, it has been widely used as an idealistic bottom building material in electric furnaces with alternative currency, direct currency, normal power, high power & super high power.

　　2. Operation Process on Electric Furnace Bottom Ramming

　　1). Before ramming, the furnaces bottom's permanent lining needs to be completely cleaned cleaned away. Nothing should be leftover.

　　2). The ramming material be laid homogeneously on the furnace bottom. Each layer be thick as 120-150mm (while number of layers be decided according to the whole thick ness of the bottom). The last layer be thick as 100mm.

　　3). Cover the surface of the ramming material with antiquated plastic woven bags or canvas (to prevent dusts during ramming).

　　4). Ram & press with vibrators, swage hammers or wooden hammers. The shrinkage rate is to be 15-20%.

　　5). After ramming, each layer is to be inspected by steel-bar insertion method on the quality. The pressure on the steel-bar is 10kg, while the insertion depth is to be 30mm maximum.

　　6). For furnace slopes, the ramming is better with steel mold layer after layer. Tiering ramming can be applied when operation conditions are limited. The tiering gradient, however, has to be 40 degree maximum. The height be limited under the slag line.

　　7). When the ramming on the bottom & the slopes are over, cover the surface with antiquated steel plates or iron sheets. This is to prevent the heavy impact from the charging of heavy steel objects.

　　8). The first charge is to be only light & thin materials. Heavy objects may break the bottom or the slope.

　　9). Fluxing oxygen blowing is prohibited for the first charge, to make the furnace atmosphere steady. Some 10-15 minutes of power cut needs to be applied at each down-to-bottom penetration & before each charging. This is to allow the vapor be released from the ramming materials. When the molten steel temperature reaches 1650C, the holding time before discharging has to be longer than 30 minute. The whole melting time is to be longer than 3 hours.

　　10). Hot fettling can be applied when pits coming out from the furnace bottom after a long service time: Discharge the molten steel completely. Blow the residual slag completely with oxygen or compressed air. Hang the ramming material to the fettling position & drop down. Press it firmly with swage hammers, then it is ready for further service.

　　11). When cold fettling is to be applied, the furnace body should be inclined to prevent the residual steel be consolidated at the furnace bottom. Otherwise the furnace bottom can be damaged when the solid steel be removed. The cold fettling to the furnace slopes is to be done after the impurity materials be cleared away from the surface.

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