Uma metodologia para a avaliação dos gradientes de tenacidade a fratura ao longo da camada cementada do aço SAE 5115 / A model for fracture toughness evaluation of the carburized layer for SAE 5115 steel

AUTOR(ES)
DATA DE PUBLICAÇÃO

2005

RESUMO

The purpose of this work is to propose a model for evaluating the fracture toughness along the SAE 5115 steel carburized layer. Due to the small thickness of those layers, it is impossible to machine specimens from those layer in accordance with standards. For simulating the microstructures of the carburized layer in order to get samples for tensile and the fracture toughness testing, specimens of SAE 5115, 5140, 5160, and 52100 steels assuming the local influence just of the variation of the content of carbon and considering that the contents of the other alloy elements are essentially constant. The specimens after electroplated copper layer were heat treated in an industrialload of carburizing, quenching, and tempering for they be submitted to the thermal effects without absorption of carbono The results of the microstructure analysis and microhardness, tension, and fracture toughness tests were placed in a single graph and compared with the profile of the carburizing of the steel SAE 5115 heat treated in the same conditions. It was confirmed that the fracture toughness varies inversely proportional to the microhardness (HV1) and that the forecast of the behavior of a crack in a carburized layer can be made through equation or it designs that relate the microhardness (HV1) with the fracture toughness (KIC or CTODc)

ASSUNTO(S)

aço - fadiga metallography steel fadigue metalografia fracture mechanics fractography mecanica da fratura case hardening aço de alta resistencia high strength steel fractografia processo de endurecimento superficial

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