A multipurpose continuous processing line able for heat treating and hot dip coating a steel strip comprising: - an annealing section comprising a preheating zone, a heating zone and a soaking zone for heating the steel strip from an ambient temperature to a predetermined annealing temperature comprised between 700°C and 1000°C and for maintaining the steel strip at said annealing temperature, - a first transfer section, - an overaging section able to maintain the temperature of the steel strip between 300° C and 700°C, the overaging section comprising controllable means able to maintain the temperature of the strip around an overaging temperature by maintaining the temperature of the strip between the overaging temperature - 10°C and the overaging temperature + 10°C, or to allow the temperature of the strip to steadily decrease between an entry temperature and an exit temperature, - a second transfer section able to adjust the temperature of the steel strip to allow the hot dip coating of the strip and, - a hot dip coating section, wherein the first transfer section comprises, in sequence, cooling means and heating means, the cooling means being able to cool the strip at an adjustable cooling rate to a predetermined quenching temperature or not to cool the strip, the cooling means being such that the cooling speed of the strip can be adjusted between 0°C/s and 70°C/s and such that the quenching temperature can be adjusted between 100°C and 500°C, the heating means of the first transfer section being controllable such that their heating capabilities are adjustable between no heating and rapid heating to a predetermined overaging temperature, the heating means comprising at least one controllable induction heater, and wherein the second transfer section comprises, in sequence, controllable cooling means and controllable heating means for adjusting the temperature of the strip by cooling or by heating, the controllable cooling means being able to cool the strip from an overaging temperature higher than the coating temperature down to the coating temperature, the controllable heating means being able to heat the strip from an overaging temperature lower than the coating temperature to the coating temperature. - an annealing section comprising a preheating zone, a heating zone and a soaking zone for heating the steel strip from an ambient temperature to a predetermined annealing temperature comprised between 700°C and 1000°C and for maintaining the steel strip at said annealing temperature, - a first transfer section, - an overaging section able to maintain the temperature of the steel strip between 300° C and 700°C, the overaging section comprising controllable means able to maintain the temperature of the strip around an overaging temperature by maintaining the temperature of the strip between the overaging temperature - 10°C and the overaging temperature + 10°C, or to allow the temperature of the strip to steadily decrease between an entry temperature and an exit temperature, - a second transfer section able to adjust the temperature of the steel strip to allow the hot dip coating of the strip and, - a hot dip coating section, wherein the first transfer section comprises, in sequence, cooling means and heating means, the cooling means being able to cool the strip at an adjustable cooling rate to a predetermined quenching temperature or not to cool the strip, the cooling means being such that the cooling speed of the strip can be adjusted between 0°C/s and 70°C/s and such that the quenching temperature can be adjusted between 100°C and 500°C, the heating means of the first transfer section being controllable such that their heating capabilities are adjustable between no heating and rapid heating to a predetermined overaging temperature, the heating means comprising at least one controllable induction heater, and wherein the second transfer section comprises, in sequence, controllable cooling means and controllable heating means for adjusting the temperature of the strip by cooling or by heating, the controllable cooling means being able to cool the strip from an overaging temperature higher than the coating temperature down to the coating temperature, the controllable heating means being able to heat the strip from an overaging temperature lower than the coating temperature to the coating temperature.