A multipurpose continuous processing line able for heat treating and hot dip coating a steel strip containing: an annealing section (1) for heating the steel strip to a predetermined annealing temperature and for maintaining the steel strip at said annealing temperature, a first transfer section (2), an overaging section (3) able to maintain the temperature of the steel strip between 300° C. and 700° C., a second transfer section (4) able to adjust the temperature of the steel strip to allow the hot dip coating of the strip and, a hot dip coating section (5), wherein the first transfer section (2) includes, in sequence, a cooling section (21) and a heating section (22).