Method of processing steel

Claim 1

A METHOD OF PROCESSING STEEL TO PRODUCE A SUBSTANTIALLY NON-AGING,DUCTILE PRODUCE COMPRISING: (A) ADDING TO A MELT OF ALUMINUM-KILLED STEEL WHICH HAS A CARBON CONTENT OF AT LEAST 0.08%, NOT MORE THAN 0.6% MANGANESE AND NOT MORE THAN 0.02% SILICON, A NITROGEN-BEARING COMPOUND IN AN AMOUNT TO PROVIDE A FINAL NITROGEN CONTENT IN THE STEEL OF FROM 0.00, TO 0.015% BY WEIGHT AND THEN SOLIDIFYING SAID MELT, (B) SUBSTANTIALLY COMPLETELY DISSOLVING SAID NITROGEN IN SAID STEEL BY MAINTAINING SAID STEEL AT NITROGEN-DISSOLUTION TEMPERATURE, (C) HOT ROLLING SAID STEEL AT A TEMPERATURE ABOVE ABOUT 1520*F., (D) RAPIDLY COOLING THE HOT ROLLED STEEL TO A TEMPERATURE BELOW ABOUT 1100*F. TO MINIMIZE PRECIPITATION OF ALUMINUM-NITRIDE AND THEREAFTER COLD REDUCING SAID STEEL, (E) ANNEALING SAID COLD REDUCED STEEL FOR A TIME SUFFICIENT TO OBTAIN A RECRYSTALLIZED, ELONGATED GRAIN STRUCTURE WHEREIN THE GRAINS ARE NOT LARGER THAN ASTM NO. 7 AND TO PRECIPITATE ALUMINUM-NITRIDE AROUND SAID GRAINS WHEREBY THE GROWTH OF SAID GRAINS DURING ANNEALING IS RESTRICTED BY SAID ALUMINUMNITRIDE, AND (F) TEMPER ROLLING TO INCREASE THE YIELD STRENGTH OF THE STEEL.

Claim 2

A METHOD OF PROCESSING STEEL TO PRODUCE A SUBSTANTIALLY NON-AGING,DUCTILE PRODUCE COMPRISING: (A) ADDING TO A MELT OF ALUMINUM-KILLED STEEL WHICH HAS A CARBON CONTENT OF AT LEAST 0.08%, NOT MORE THAN 0.6% MANGANESE AND NOT MORE THAN 0.02% SILICON, A NITROGEN-BEARING COMPOUND IN AN AMOUNT TO PROVIDE A FINAL NITROGEN CONTENT IN THE STEEL OF FROM 0.00, TO 0.015% BY WEIGHT AND THEN SOLIDIFYING SAID MELT, (B) SUBSTANTIALLY COMPLETELY DISSOLVING SAID NITROGEN IN SAID STEEL BY MAINTAINING SAID STEEL AT NITROGEN-DISSOLUTION TEMPERATURE, (C) HOT ROLLING SAID STEEL AT A TEMPERATURE ABOVE ABOUT 1520*F., (D) RAPIDLY COOLING THE HOT ROLLED STEEL TO A TEMPERATURE BELOW ABOUT 1100*F. TO MINIMIZE PRECIPITATION OF ALUMINUM-NITRIDE AND THEREAFTER COLD REDUCING SAID STEEL, (E) ANNEALING SAID COLD REDUCED STEEL FOR A TIME SUFFICIENT TO OBTAIN A RECRYSTALLIZED, ELONGATED GRAIN STRUCTURE WHEREIN THE GRAINS ARE NOT LARGER THAN ASTM NO. 7 AND TO PRECIPITATE ALUMINUM-NITRIDE AROUND SAID GRAINS WHEREBY THE GROWTH OF SAID GRAINS DURING ANNEALING IS RESTRICTED BY SAID ALUMINUMNITRIDE, AND (F) TEMPER ROLLING TO INCREASE THE YIELD STRENGTH OF THE STEEL.