A method for dynamic control of the converter process in the blowing of oxygen in steel-making by means of exhaust gas analyses with the help of a process model with static process computation and with the help of a sub-model, which is independent of the process model, with dynamic process observation, which operates as a process observer based on waste gas analysis, wherein the process model and the sub-model are components of a regulating circuit which comprises process observation and management with a measuring system, signal preparation, the sub-model as process observer, and process checking or process management, as well as a process procedure with a converter and process control or process operation, and in which waste gas samples, which comprise at least the waste gas constituents O 2, CO and CO 2, of the converter are analysed in the measuring system, and the obtained signals, which correspond with the analytical values, are prepared in the signal preparation, and subsequently thereto data correcting the original process model by static process computation flow from the sub-model into the process control or management for process control or process operation, wherein with the help of the sub-model, which is independent of the process model, computation is carried out, through a feasible combination of the obtained constituent signals, of detection values for the critical decarburisation instant (t' crit) and for the end of O 2 blowing (t' EoB), by which the oxygen content predicted by the process model is corrected at the start of the process and adapted to the actual conditions towards the end of the decarburisation period, wherein the critical decarburisation time (t' crit) is expressed by: t = t crit ' when CP t ≥ CPP and CP t = N 2 ∧ n / CO ∧ m wherein CCP = limit parameter, CP = (N 2)^n / ^m for converters with a gap and low CO post-combustion, CP = (N 2 /CO 2)^s for converters without a gap and high CO post-combustion, and the end of O 2 blowing (t' EoB) is expressed by: t = t' EoB when EoB t ≥ EoBP 1 and EoB = CO + CO 2 − rPC wherein post-combustion in %= PC = CO 2 /(CO + CO 2) 100 and EoBP1 = limit parameter, and the parameters in the equations for the critical decarburisation instant and for the end of O 2 blowing are dependent on the converter design and particularly on the availability of gap adjustment and are to be adapted at regular intervals, wherein the adjustment ranges are n = 6 - 7; m = 3 - 6; s = 3 - 4; r = 0 - 5. CCP = limit parameter, CP = (N 2)^n / ^m for converters with a gap and low CO post-combustion, CP = (N 2 /CO 2)^s for converters without a gap and high CO post-combustion, and the end of O 2 blowing (t' EoB) is expressed by: t = t' EoB when EoB t ≥ EoBP 1 and EoB = CO + CO 2 − rPC wherein post-combustion in %= PC = CO 2 /(CO + CO 2) 100 and EoBP1 = limit parameter, and the parameters in the equations for the critical decarburisation instant and for the end of O 2 blowing are dependent on the converter design and particularly on the availability of gap adjustment and are to be adapted at regular intervals, wherein the adjustment ranges are n = 6 - 7; m = 3 - 6; s = 3 - 4; r = 0 - 5. post-combustion in %= PC = CO 2 /(CO + CO 2) 100 and EoBP1 = limit parameter, and the parameters in the equations for the critical decarburisation instant and for the end of O 2 blowing are dependent on the converter design and particularly on the availability of gap adjustment and are to be adapted at regular intervals, wherein the adjustment ranges are n = 6 - 7; m = 3 - 6; s = 3 - 4; r = 0 - 5.