Method to weld billets leaving a furnace and a rolling line adopting the method

摘要

Method is for welding billets leaving a heating furnace in a rolling line, the line including, in the segment (10) between the heating furnace (11) and the first rolling stand, at least a drawing unit (14), a rollerway to transport the billets, a movable welding assembly (20) with welding jaws (31) and an emergency shears (13). The trailing end of the billet (12a) being rolled is welded to the leading end of the billet (12b) unloaded afterwards from the furnace (11) while the billets (12) are in movement by a welding assembly (20) mounted on a movable trolley (19). The movable trolley (19) is taken substantially to the rolling speed, grips the billets (12) with the jaws (31) of the welding unit (20) and welds the ends of the billets (12). The welding step is preceded by a descaling step carried out by a descaling unit (16) wherein the front faces of the billets (12) and at least those areas of the billets (12) cooperating with the jaws (31) are descaled and by a parallel plane cropping step of the trailing end and leading end of the billets (12) carried out by a cropping unit (29) mounted on the movable trolley (19) immediately upstream of the welding assembly (20). The welding step is followed by a step to remove the flashes carried out by a flash removal unit (38) while the billet (12) is in movement.