Process for producing doubly oriented cube-on-face magnetic sheet material

Claim 1

IN A PROCESS FOR PRODUCING MAGNETIC SHEET OF A THICKNESS OF AT LEAST 8 MILS WITH CUBE-ON-FACE, DOUBLE ORIENTED CRYSTAL ORIENTATION, THE STEPS COMPRISING, HOT ROLLING AN INGOT OF A MAGNETIC SILICON-IRON ALLOY CONTAINING FROM 2% TO 5% SILICON, FROM 0.05% TO 0.4% MANGANESE AND AT LEAST ONE OTHER ELEMENT SELECTED FROM THE GROUP CONSISTING OF FROM 0.1% TO 2% MOLYBDENUM, FROM 0.1% TO 2.0% CHROMIUM AND FROM 0.1% TO 1% NICKEL TO A SLAB OF PREDETERMINED THICKNESS OF AT LEAST 8 MILS SLAB AT LEAST TO A FINAL GUAGE THICKNESS OF AT LEAST 8 MILS TWICE, EACH COLD ROLLING STEP EFFECTING A DEFORMATION OF AT LEAST 30% AND NOT MORE THAN 80% IN THICKNESS, INTERMEDIATE ANNEALING THE SHEET AT LEAST ONCE A TEMPERATURE OF FROM 975* C. TO 1200* C. IN AN ATMOSPHERE OF DRY HALOGEN FOR A PERIOD OF TIME TO PRODUCE PRIMARY RECRYSTALLIZATION AND GRAIN GROWTH IN WHICH THE AVERAGE GRAIN DIAMETER IS AT LEAST HALF THE THICKNESS OF THE SHEET WHICH RECRYSTALLIZED SHEET WILL RESPOND TO FURTHER PROCESSING TO BECOME DOUBLY ORIENTED, AND AFTER THE FINAL COLD ROLLING STEP HEAT TREATING THE MAGNETIC SHEET AT A TEMPERATURE OF FROM ABOUT 1100* C. TO 1350* C. IN AN ATMOSPHERE OF DRY HALOGEN HAVING A DEW POINT OF AT LEAST -30* C. FOR A PERIOD OF TIME SUFFICIENT TO PROMOTE SUBSTANTIALLY COMPLETE SECONDARY GRAIN GROWTH, THE SHEET AT THE TIME OF SECONDARY RECRYSTALLIZATION HAVING A SULFUR CONTENT OF BELOW 0.001% BUT ABOVE ABOUT 0.00003% AND AN OXYGEN CONTENT BELOW 0.005%, WHEREBY TO PRODUCE A DOUBLY ORIENTED CUBE-ON-FACE MAGNETIC SHEET OF THE FINAL THICKNESS.