Análise crítica do ensaio de determinação da curva mestre (ASTM E 1921) aplicado a um aço da classe API 5L X80. / Critique analyse of essay of determination of master curve (ASTM E 1921) applied the an API 5L X80 steel.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2011

RESUMO

One of the key aspects of structural integrity is the consideration of scale effects characteristic of materials wich present quase-brittle behavior. The Master curve method, designed for ferritic steels operating at temperatures in the materials corresponding to the ductile-brittle transition. This method combine charpy impact testing and a few fracture toughness tests in standard specimens and is supposedly able to reproduce the materials fracture toughness in the whole ductile-to-brittle transition temperature interval for any characteristic size of the structure. This method relies on the basic hypothesis that fracture is initiated by cleavage the most brittle micro constituent (generally ferrite). This work investigates this hypothesis by comparing the fracture surfaces obtained under the loading conditions of the different mechanical tests used in the method (tensile, impact and J.R. curve) for the determination of the master curve of an API 5L X80 steel. The results show that these fracture surfaces indicate the action of different fracture micro mechanisms raising doubts on the applicability of the method.

ASSUNTO(S)

aço (propriedades mecânicas) ductile ductilidade ensaios dos materiais fracture mechanics fracture thougness materials essay mecânica da fratura steel (mechanics propriety) tenacidade dos materiais

ACESSO AO ARTIGO

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