Method of hardening hypereutectoid steels

Claim 1

A METHOD OF HARDENING HYPEREUTECTOID STEELS HAVING LESS THAN ABOUT 5% TOTAL ALLOY CONTENT COMPRISING HEATING SAID STEEL TO A TEMPERATURE IN THE RANGE OF ABOUT 1700 TO ABOUT 200*F. FOR A TIME SUFFICIENT TO FORM AUSTENITE AND TO DISSOLVE IN SAID AUSTENITE ALL CARBIDES, RAPIDLY QUENCHING TO BELOW THE MS TEMPERATURE TO FORM A MIXTURE OF MARTENSITE AND AUSTENTITE, REHEATING INTO THE BAINITE FORMING TEMPERATURE RANGE AND HOLDING THEREIN FOR A TIME SUFFICIENT TO TRANSFORM SUBSTANTIALLY ALL THE AUSTENTITE TO BAINITE AND TO TEMPER THE MARTENSITE TO A MIXTURE OF FINE CARBIDES AND FERRITE, REHEATING TO A TEMPERATURE IN THE RANGE OF 1425 TO 1600*F. FOR A TIME SUFFICIENT TO CONVERT SUBSTANTIALLY ALL FERRITE TO AUSTENTITE BUT INSUFFICIENT TO CAUSE SUBSTANTIAL GROWHT OF ANY FINE CARBIDES PRESENT AND FINALLY COOLING TO HARDEN THE STEEL AND PRODUCE A FINE-GRAINED STRUCTURE WITH AN AUSTENITE GRAIN SIZE FINER THAN ASTM #10 AND A DISPERION OF UNIFORMLY FINE CARBIDES.

Claim 2

A METHOD OF HARDENING HYPEREUTECTOID STEELS HAVING LESS THAN ABOUT 5% TOTAL ALLOY CONTENT COMPRISING HEATING SAID STEEL TO A TEMPERATURE IN THE RANGE OF ABOUT 1700 TO ABOUT 200*F. FOR A TIME SUFFICIENT TO FORM AUSTENITE AND TO DISSOLVE IN SAID AUSTENITE ALL CARBIDES, RAPIDLY QUENCHING TO BELOW THE MS TEMPERATURE TO FORM A MIXTURE OF MARTENSITE AND AUSTENTITE, REHEATING INTO THE BAINITE FORMING TEMPERATURE RANGE AND HOLDING THEREIN FOR A TIME SUFFICIENT TO TRANSFORM SUBSTANTIALLY ALL THE AUSTENTITE TO BAINITE AND TO TEMPER THE MARTENSITE TO A MIXTURE OF FINE CARBIDES AND FERRITE, REHEATING TO A TEMPERATURE IN THE RANGE OF 1425 TO 1600*F. FOR A TIME SUFFICIENT TO CONVERT SUBSTANTIALLY ALL FERRITE TO AUSTENTITE BUT INSUFFICIENT TO CAUSE SUBSTANTIAL GROWHT OF ANY FINE CARBIDES PRESENT AND FINALLY COOLING TO HARDEN THE STEEL AND PRODUCE A FINE-GRAINED STRUCTURE WITH AN AUSTENITE GRAIN SIZE FINER THAN ASTM #10 AND A DISPERION OF UNIFORMLY FINE CARBIDES.