Process for improving stress corrosion cracking resistance of alloyed steel in hydrogen sulphide atmosphere

Claim 1

A PROCESS FOR MANUFACTURING AN ALLOYED STEEL ELEMENT HAVING FINE SPHEROIDIZED CARBIDE PARTICLES UNIFORMLY DISTRIBUTED IN THE FERRITIC IN A MOIST ATMOSPHERE CHARGED SION CRACKING RESISTANCE IN A MOIST ATMOSPHERE CHARGED WITH HYDROGEN SULFIDE INCLUDING THE STEPS OF AUSTENITIZING AN ALLOYED STEEL ELEMENT HAVING A COMPOSITION COMPRISING FROM 0.10 TO 0.25% CARBON, FROM 0.10 TO 0.50% SILICON, FROM 0.30 TO 1.0% MANGANESE, FROM 1 TO 14% CHROMIUM, FROM 0.40 TO 1.5% MOLYBDENUM, FROM 0.10 TO 0.60% VANADIUM, FROM 0 TO 1% NICKEL, AND MINOR QUANTITIES OF OTHER ELEMENTS SUCH AS SULFUR UP TO 0.030%, PHOSPHORUS UP TO 0.025%, COPPER UP TO 0.20%, THE REMAINDER BEING SUBSTANTIALLY ALL IRON, AT A TEMPERATURE BETWEEN 975* AND 1100* C., COOLING THE STEEL AT A SPEED AT LEAST EQUAL TO 30* C. PER MINUTE BETWEEN 850* AND 600* C., AND THEN TEMPERING THE STEEL AT A TEMPERATURE BETWEEN 725* AND 800* C. FOR A PERIOD OF TIME SUFFICIENT TO PRODUCE A YIELD POINT BETWEEN 55 AND 65 KG./MM.2, ACCORDING TO THE AMOUNT OF CARBON.