POTENTIAL FOR IMPROVEMENTS IN MECHANICAL PROPERTIES OF AISI 9260 STEEL BY QUENCHING AND PARTITIONING HEAT TREATMENT
POTENCIAL PARA MELHORIAS NAS PROPRIEDADES MECÂNICAS DO AÇO AISI 9260 ATRAVÉS DO TRATAMENTO TÉRMICO DE TÊMPERA E PARTICIONAMENTO
Lauro Correa Romeiro, Nestor Cezar Heck, Danilo Assad Ludewigs
Abstract
In this work the quenching and partitioning (Q&P) treatment is applied to AISI 9260 steel combining different quenching temperatures (QT), and partitioning times and temperatures in order to evaluate mechanical properties (e.g. ultimate tensile strength, elongatin, toughness, and their combination). AISI 9260 steel, besides having the advantage of a lower cost than most of the low alloy steels, can achieve high retained austenite (RA) fraction levels through the application of the Q&P treatment thanks to its few alloying elements, mainly silicon. The importance of RA lies in its ability to improve ductility and toughness; in this work, RA is determined via X-ray diffraction analysis (XRD) and the mechanical properties are assessed through conventional tensile test and, fracture toughness test (FT) – FT being seldom reported in several Q&P studies. The results of the present work suggest that the Q&P treatment applied to AISI 9260 steel could increase its industrial use by virtue of a good combination of strength, ductility and toughness.
Keywords
Resumo
Neste trabalho, o tratamento de têmpera e particionamento (Q&P) é aplicado ao aço AISI 9260 combinando diferentes temperaturas de têmpera (QT) e tempos e temperaturas de particionamento para avaliar as propriedades mecânicas (resistência à tração, alongamento, tenacidade e sua combinação). O aço AISI 9260, além de ter a vantagem de um custo menor do que a maioria dos aços de baixa liga, pode alcançar altos níveis de fração de austenita retida (AR) através da aplicação do tratamento Q&P graças aos seus poucos elementos de liga, principalmente silício. A importância da AR consiste na sua capacidade de melhorar a ductilidade e a tenacidade; neste trabalho, a AR é determinada por análise de difração de raios-X (DRX) e as propriedades mecânicas são avaliadas através de ensaio de tração convencional, e do teste de tenacidade à fratura (FT) - FT é raramente relatado em vários estudos com tratamento Q&P. Os resultados do presente trabalho sugerem que o tratamento Q&P aplicado ao aço AISI 9260 pode ampliar seu uso industrial em virtude de uma boa combinação de resistência, ductilidade e tenacidade.
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Referências
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