COBEM99

S3 Ciências dos Materiais

Title:

MECHANICAL BEHAVIOR OF A WARM-ROLLED VANADIUM MICROALLOYED MEDIUM CARBON STEEL

Summary :

ABSTRACT. THE APPLICATION OF SMALL MICROALLOYING ADDITIONS IN CARBON STEEL IS WELL KNOWN. ADDITION ELEMENTS SUCH AS NIOBIUM AND VANADIUM CAN HAVE A NUMBER OF EFFECTS ON THE MICROSTRUCTURE WHICH AFFECT THE MECHANICAL PROPERTIES OF MICROALLOYED STEELS. THESE EFFECTS INCLUDE NITROGEN FIXING, GRAIN REFINEMENT, INTERLAMELLAR SPACING AND PRECIPITATION STRENGTHENING. IN MEDIUM CARBON STEELS THE LIMITED SOLUBILITY OF NIOBIUM IN AUSTENITE AT NORMAL SOAKING TEMPERATURES RESTRICTS THE POTENTIAL OF THIS ELEMENT. HOWEVER, AS VANADIUM SHOWS A HIGH LEVEL OF SOLUBILITY, SIGNIFICANT LEVELS OF DISPERSION STRENGTHENING IN VANADIUM MICROALLOYED STEELS HAVE ALLOWED THE DEVELOPMENT OF MEDIUM CARBON FORGING STEELS FOR SEVERAL APPLICATIONS SUCH AS CONNECTING RODS AND STEERINGS LINKAGES. THE STRENGTH LEVEL ATTAINED IN MICROALLOYED MEDIUM CARBON STEELS AND COST SAVINGS BY DEVELOPING THE PROPERTIES WITHOUT HEAT TREATMENT HAVE RESULTED IN AN EXTENSIVE APPLICATION OF THOSE STEELS IN INDUSTRIAL SCALE. THIS WORK HAS STUDIED THE MECHANICAL BEHAVIOR UNDER WARM WORK OF A VANADIUM MICROALLOYED MEDIUM CARBON STEEL IN THE INTERCRITICAL TEMPERATURE RANGE FOCUSED IN THE DECOMPOSITION OF THE FERRITE-AUSTENITE. ISOTHERMAL CONTINUOUS AND INTERRUPTED TORSION TESTS WERE CARRIED OUT FOR TEMPERATURES RANGING FROM 1100 C TO 600 C AND WITH DEFORMATION RATE OF 0.5 AND 1.S-1 . KEYWORDS: MICROALLOYED STEEL, WARM WORK, TORSION TESTS

Author :

Balancin, Oscar 0
Lourenço, Nicélio José

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