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S3 Ciências dos Materiais |
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Title:
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ABNT M2 HIGH SPEED STEEL HEAT TREATMENT.
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Summary :
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THIS PAPER DESCRIBES THE AUSTENITIZING AND TEMPERING CONDITIONS INFLUENCE IN ABNT M2 MICROSTRUCTURE AND HARDNESS. THE AUSTENITIZATION TEMPERATURES USED CHANGED FROM 900OC TO 1200°C FOR PERIODS UP TO 30 MINUTES; AT TEMPERING, TEMPERATURE WAS CHANGED BETWEEN 250°C AND 700°C, FOR PERIODS UP TO 120 HOURS. IT WAS FOUND THAT MAXIMUM HARDNESS IS ACHIEVED WHEN AUSTENITIZATION WERE CONDUCTED AT 1175°C FOR 5 MINUTES, AND AUSTENITIZATION AT 900°C AND 1000°C ARE NOT SUFFICIENT TO GIVE THE CORRECT AUSTENITE FORMATION AND CARBIDE DISSOLUTION, GIVING STRUCTURES OF LOW HARDNESS. AUSTENITIZING AT 1220°C, OR FOR TIME PERIODS BIGGER THAN 5 MINUTES, RESULTS IN EXCESSIVE GRAIN GROWING AND THE LOWEST UNDISSOLVED CARBIDE FRACTION, RESULTING IN HIGHER BRITLENESS AND POOR ABRASION RESISTANCE. IN TEMPERING, THE MAXIMUM HARDNESS RESULTING FROM CARBIDE PRECIPITATION (CALLED SECONDARY HARDENING) OCCURS AT 550°C FOR 2,5 HOURS, AND MICROSTRUCTURE DIFFERENCES COULD ONLY BE OBSERVED WITH OPTICAL MICROSCOPY AFTER THE HIGHEST TIME AND TEMPERATURE USED.
KEY WORDS: HIGH SPEED STEEL, ABNT M2, HEAT TREATMENT.
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Author :
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MAGNABOSCO, RODRIGO 0
Oliva-Jr., Roberto Zitelman
Passos, Ronan Rocha S.
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Paper View :
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