| 摘要 |
AN ULTRA-HIGH STRENGTH, WELDABLE, LOW ALLOY, TRIPLE PHASE STEEL WITH EXCELLENT CRYOGENIC TEMPERATURE TOUGHNESS IN THE BASE PLATE AND IN THE HEAT AFFECTED ZONE (HAZ) WHEN WELDED, HAVING A TENSILE STRENGTH GREATER THAN ABOUT 830 MPA (120 KSI) AND A MICROSTRUCTURE COMPRISING A FERRITE (14) PHASE, A SECOND PHASE (16) OF PREDOMINANTLY LATH MARTENSITE (32) AND LOWER BAINITE, AND A RETAINED AUSTENITE (42) PHASE, IS PREPARED BY HEATING A STEEL SLAB COMPRISING IRON AND SPECIFIED WEIGHT PERCENTAGES OF SOME OR ALL OF THE ADDITIVES CARBON, MANGANESE, NICKEL, NITROGEN, COPPER, CHROMIUM, MOLYBDENUM, SILICON, NIOBIUM, VANADIUM, TITANIUM ALUMINUM, AND BORON; REDUCING THE SLAB TO FORM PLATE IN ONE OR MORE PASSES IN A TEMPERATURE RANGE IN WHICH AUSTENITE RECRYSTALLIZES; FURTHER REDUCING THE PLATE IN ONE OR MORE PASSES IN A TEMPERATURE RANGE BELOW THE AUSTENITE RECRYSTALLIZATION TEMPERATURE AND ABOVE THE AR3 TRANSFORMATION TEMPERATURE; FINISH ROLLING THE PLATE BETWEEN THE AR3 TRANSFORMATION TEMPERATURE AND THE AR1 TRANSFORMATION TEMPERATURE; QUENCHING THE FINISH ROLLED PLATE TO A SUITABLE QUENCH STOP TEMPERATURE (QST); AND STOPPING THE QUENCHING. (FIGURE 3)
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