Method of heat treating metallic pipes

Claim 1

THE METHOD OF PRODUCING HEAT TREATED PIPE HAVING A D/T RATIO IN EXCESS OF 10 COMPRISING FORMING PIPE OF STEEL CONTAINING .15 TO .50% CARBON .50 TO 2.00% MANGANESE .01 TO .15% PHOSPHORUS .06% MAX. SULPHUR BALANCE IRON AND OTHER ELEMENTS IN AMOUNTS WHICH DO NOT ADVERSELY AFFECT THE PROPERTIES, HEATING SAID PIPE TO ABOVE THE UPPER CRITICAL TEMPERATURE THEREOF, QUENCHING SAID HEATED PIPE TO OBTAIN IN SAID STEEL A MARTENSITIC STRUCTURE WHICH WHEN COMPRESSED AT A TEMPERATURE ABOVE 600 AND BELOW 1000* F. WILL FIRST INCREASE IN COMPRESSION YIELD STRENGTH AND UPON FURTHER COMPRESSION WITHIN SAID TEMPERATURE RANGE WILL THEN DECREASE IN COMPRESSION YIELD STRENGTH, THE QUENCHING OF SAID PIPE CAUSING OVALITY THEREIN, HEATING THE QUENCHED PIPE TO A TEMPERATURE WITHIN THE AFOREMENTIONED RANGE, REDUCING THE DIAMETER OF SAID PIPE AN AMOUNT SUFFICIENT TO REMOVE SAID OVALITY BUT NOT OVER 3% BY COMPRESSION WHILE IN SAID TEMPERATURE RANGE TO FIRST INCREASE THE COMPRESSION YIELD STRENGTH OF THE PIPE AND THEN DECREASE THE SAME, AND REGULATING THE AMOUNT OF COMPRESSION WITHIN SAID RANGE TO AN AMOUNT INSUFFICIENT TO REDUCE SAID YIELD STRENGTH SUBSTANTIALLY BELOW THE VALUE OF THE SAME IF THE QUENCHED PIPE WERE SIMPLY TEMPERED AT THE TEMPERATURE OF SAID HEATING AND COMPRESSION.

Claim 2

THE METHOD OF PRODUCING HEAT TREATED PIPE HAVING A D/T RATIO IN EXCESS OF 10 COMPRISING FORMING PIPE OF STEEL CONTAINING .15 TO .50% CARBON .50 TO 2.00% MANGANESE .01 TO .15% PHOSPHORUS .06% MAX. SULPHUR BALANCE IRON AND OTHER ELEMENTS IN AMOUNTS WHICH DO NOT ADVERSELY AFFECT THE PROPERTIES, HEATING SAID PIPE TO ABOVE THE UPPER CRITICAL TEMPERATURE THEREOF, QUENCHING SAID HEATED PIPE TO OBTAIN IN SAID STEEL A MARTENSITIC STRUCTURE WHICH WHEN COMPRESSED AT A TEMPERATURE ABOVE 600 AND BELOW 1000* F. WILL FIRST INCREASE IN COMPRESSION YIELD STRENGTH AND UPON FURTHER COMPRESSION WITHIN SAID TEMPERATURE RANGE WILL THEN DECREASE IN COMPRESSION YIELD STRENGTH, THE QUENCHING OF SAID PIPE CAUSING OVALITY THEREIN, HEATING THE QUENCHED PIPE TO A TEMPERATURE WITHIN THE AFOREMENTIONED RANGE, REDUCING THE DIAMETER OF SAID PIPE AN AMOUNT SUFFICIENT TO REMOVE SAID OVALITY BUT NOT OVER 3% BY COMPRESSION WHILE IN SAID TEMPERATURE RANGE TO FIRST INCREASE THE COMPRESSION YIELD STRENGTH OF THE PIPE AND THEN DECREASE THE SAME, AND REGULATING THE AMOUNT OF COMPRESSION WITHIN SAID RANGE TO AN AMOUNT INSUFFICIENT TO REDUCE SAID YIELD STRENGTH SUBSTANTIALLY BELOW THE VALUE OF THE SAME IF THE QUENCHED PIPE WERE SIMPLY TEMPERED AT THE TEMPERATURE OF SAID HEATING AND COMPRESSION.