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Influence of Temperature and Time of Austempering Treatment on Mechanical Properties of SAE 9254 Commercial Steel
Author(s) -
Cruz J. A.,
Rodrigues T. F. M.,
Viana V. D. C.,
Abreu H.,
Santos D. B.
Publication year - 2012
Publication title -
steel research international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.603
H-Index - 49
eISSN - 1869-344X
pISSN - 1611-3683
DOI - 10.1002/srin.201100174
Subject(s) - materials science , austempering , martensite , ultimate tensile strength , austenite , metallurgy , bainite , fracture (geology) , isothermal process , brittleness , brittle fracture , yield (engineering) , composite material , microstructure , physics , thermodynamics
Abstract This work describes the steps in the study and development of the high content of C, Si, and Cr in commercial steel with a nanostructured matrix of martensite, bainite and retained austenite. Specimens of this steel were austenitized at 900 °C for 5 min and isothermally heat treated at different times (0.5, 2, 24, 48 h) and temperatures (200, 220, 270 °C). Different mechanical behavior was observed for the samples treated under different conditions due to their microstructural constitution. Specimens treated for 2 h at 200 °C showed lower yield strength of 979 MPa. On the other hand a high tensile strength of 2248 MPa was reached. The sample treated at 270 °C showed higher yield strength of 1363 MPa with the same treatment time. As for the fracture analysis, the brittle fracture mechanism was predominant for the samples treated at 200 °C, while the ductile fracture mechanism was predominant for the samples treated at 270 °C.