Method of hot rolling nickel-iron magnetic sheet stock

Claim 1

A PROCESS FOR THE PRODUCTION OF NICKEL-IRON ALLOY SHEET STOCK HAVING IMPROVED MAGNETIC PROPERTIES, WHICH PROCESS INCLUDES THE STEPS OF FORMING A NICKEL-IRON ALLOY CONSISTING ESSENTIALLY OF SUBSTANTIALLY EQUAL PARTS OF NICKEL AND IRON, LESS THAN ABOUT .035% CARBON, AND SULFUR BETWEEN .0030% AND .010%, OTHER ALLOYING INGREDIENTS BEING MINOR IN AMOUNT, CASTING THE SAID ALLOY INTO INGOTS, HOT ROLLING THE SAID INGOTS TO AN INTERMEDIATE GAUGE OF ABOUT .125" TO ABOUT .180" UNDER SUCH CONDITIONS THAT THE HOT ROLLING WILL BE CONNECTED WITH THE INGOTS AT TEMPERATURES FROM ABOUT 2200*F. TO ABOUT 2300*F., THAT THE TEMPERATURE OF THE MATERIAL WHEN AT A SLAB THICKNESS OF SUBSTANTIALLY 3" TO 6" AND READY FOR FURTHER ROLLING WILL RANGE FROM ABOUT 1850*F. TO ABOUT 2050*F., THAT THE HOT ROLLING IS FINISHED AT TEMPERATURES OF ABOUT 1300*F. TO ABOUT 1500*F. AND THAT THE HOT ROLLED MATERIAL IS COILED AT A TEMPERATURE NOT GREATER THAN ABOUT 11000* F., COLD ROLLING THE MATERIAL TO A FINAL GAUGE OF ABOUT 1/4 TO ABOUT 14 MILS AND THEN SUBJECTING THE COLD ROLLED MATERIAL TO AN ANNEAL IN DRY HYDROGEN AT A TEMPERATURE OF SUBSTANTIALLY 1800*F. TO SUBSTANTIALLY 2200*F. FOR ABOUT ONE TO FOUR HOURS.