In Order to optimize and shorten this period it is required to enter in a stove the certain amount of energy so that to minimize general duration of melting and effectively to use acting and appearing as a result of flowing of exothermic reactions warmly. An economy is attained as a result: reductions of general duration of melting; increases KPD voltaic arc; minimizations of duration of finding of liquid steel are in a stove; making foam of slag; pneumatic interfusion of bath; automations of melting; effective use of monoxide of carbon of the stove atmosphere due to the input of additional amount of oxygen in working space DSP by the special devices of different construction. A not small role in optimization of thermal balance is played by the use of physical heat of part of metal and slag, abandoned from the previous melting(«bog»).
Smelting in a stove on a liquid remain from the previous melting improves the terms formation of slag, instrumental in the early forming of slag and creates favourable terms for dephosphorizing. From the technological point of view most full the requirements of initial slag fusion are answered by the eventual slag of "liquid" period of melting of next him. composition (%): CaO 25-32; MgO 5-7; Sio2 12-15; FeO 30-35; Fe2O3 5-10; MnO 5-8. This slag in an amount 1,0-1,5 t remains in a stove together with part of metal of the previous melting. A remaining from the previous melting «bog» allows at process control to enter maximal power taking into account the temperature of lining-up walls of stove.
Steelworkers resulted in a table 1 enterprises made sure in practice, that "bog", leave from the previous melting allows quickly melt a charge and select maximal power in a stove. The stable electric mode, allowing to enter the maximally possible level of active-power in working space of stove, is provided. Warmly liquid remain in the process of melting of heaping up on the separate melting can arrive at 30% from an in theory necessary heat.
Some picture is got in Ansys.
The geometrical model of calculation area plugs in itself the layer of slag (200 mm in high) and steel (about 250 mm). Because an area has a plane of symmetry, its half is considered (geometrical sizes are accepted for 100 t of EAF).
On the topside of slag the coefficient of heat emission (550 Vt/m2K) is set, on a side became thermal stream 150000 Vt/m2. a thermal stream on the plane of symmetry is equal to the zero. Temperature of all points of slag and steel in initial moment of time 1620 hail. Duration of process 300 sec (5min.). As a result the picture of distribution of temperature is got in a slag and steel.
Minimum value of temperature 1040 degrees.
Maximal value of temperature 1620 became degrees .
Mean value of temperature 1435 became degrees.
Stake of volume became with a temperature less than 1420 degrees – 47 %.
Presently optimum mass of «bog», which must ostavlyat'sya in a stove, is not certain exactly, and this index for most enterprises hesitates scope from 10 to 15 % from general mass of melting.
About expedience of application of liquid remain in an arc steel-smelting stove from the previous melting «bog» talks circumstance that many enterprises successfully apply this technology due to the row of advantages as compared to work of EAF fully on a hard charge.
During the writing of this abstract master's degree work is not yet complete. Final completion: December of 2012. Complete text of work and materials on the topic can be got for an author or his leader after the named date.