Method of controlling tensions in continuous annealing furnace and system therefor

A method of controlling tensions of a steel strip in the heating, soaking and at least one cooling zones in a continuous annealing furnace of the type including helper rolls in each of the heating, soaking and cooling zones for guiding the steel strip and tension controllers provided at an input and output of said continuous annealing furnace, said method comprising:

• providing a master speed hearth roll at a predetermined position between the helper rolls of the soaking zone and the helper rolls of the cooling zone, said master speed hearth roll acting as a boundary between said heating and soaking zones and said cooling zone;
• controlling a speed of said steel strip by controlling a speed of rotation of said master speed hearth roll to be a preset value;
• sensing a tension of said steel strip in each of said heating, soaking and cooling zones;
• controlling a tension on said steel strip in said heating and soaking zones and said tension controller at said input of said continuous annealing furnace in response only to said sensed tension in said heating and soaking zones;
• and
• controlling a tension on said steel strip in said cooling zone and said tension controller at said output of said continuous annealing furnace in response only to said sensed tension in said cooling zone.