METHOD OF CONTROL OF HEATING METAL IN BELL-TYPE FURNACE Russian patent published in 2000 - IPC

FIELD: metallurgy; heat treatment of ferrous metals; control and regulation processes; manufacture of wide-strip steel. SUBSTANCE: method includes stepped heating at respective number of intervals; flow rate of fuel is changed at temperature of heating medium equal to 650 to 680 C; simultaneously, the following data are calculated: base time τ_b of temperature rise to preset magnitude where τ_t is total preset time of heating metal; is total preset holding time, from 2 to 4, rate of temperature rise every 5 minutes and remaining time of attaining preset magnitude τ_r . Magnitude τ_r is compared with actual remaining time τ_f at τ_f > τ_r, flow rate of fuel is reduced or is left without change, provided rate of temperature rise in first three five- minute cycles is constant. Flow rate of fuel is varied till temperature of shield gas under muffle of bell-type furnace T_g has reached preset magnitude T_d.r., after which intervals are made for minimization of deviation of T_g.i. from T_d.r. at continuous measurement of magnitudes T_g.i. and T_c.i.; fixed magnitudes T_g.f. and T_c.f. are compared with magnitudes T_d.i. and T_g.p., T_g.i. and T_g.f., T_c.i. and T_с.f. flow rate of fuel is changed in proportion with sign and magnitude of algebraic sum. EFFECT: reduced consumption of fuel; reduced temperature drops in volume of charge; increased yield of metal of complex drawing category. 1 dwg, 1 tbl