Influência da austenita retida no crescimento de trincas curtas superficiais por fadiga em camada cementada de aço SAE 8620 / The influence of retained austenite on short fatigue crack growth in case carburized SAE 8620 steel

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

02/10/1997

RESUMO

The retained austenite is always present in case carburized steel microstructure in small or high percentages. Since it is a ductile phase, its presence has long been a controversial subject. The influence of retained austenite on short fatigue crack propagation in case carburized SAE 8620 steel was studied in this work. Four-point-bend fatigue tests were carried out at room temperature in specimens without notch using three levels of stress range and a stress ratio of 0.1. Four different amount of retained austenite in the case carburized microstructure were obtained through different cycles of carburizing and heat treating. The retained austenite content was measured by X-ray technique, and the surface short crack growth was monitored by means of acetate replication technique. Crack length versus number of cycles and crack growth rate versus mean crack length were obtained as results. Specimens with higher levels of retained austenite in the carburized case showed longer fatigue life.

ASSUNTO(S)

austenita retida camada cementada case carburized crescimento de trincas curtas por fadiga retained austenite short fatigue crack growth

ACESSO AO ARTIGO

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