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Enhancement of Mechanical Properties in Bainitic Steel Processed from Different Austenitization Temperatures
Author(s) -
Mandal Gurudas,
Tewary Nisith Kumar,
Ghosh Swarup Kumar
Publication year - 2018
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.201700259
Subject(s) - materials science , bainite , microstructure , metallurgy , ultimate tensile strength , martensite , ferrite (magnet) , austenite , lath , ductility (earth science) , carbide , isothermal process , austempering , composite material , creep , physics , thermodynamics
A novel high strength steel has been thermo‐mechanically controlled processed (TMCP) with 750 °C finish rolling temperature followed by air cooling. Subsequently, the air‐cooled steel is partially and fully austenitised separately prior to isothermal bainitic treatment (IBT) followed by air cooling. TMCP steel reveals a congregation of ferrite–bainite–martensite microstructure resulting in an effective combination of strength and ductility. After IBT, multiphase microstructures comprising ferrite, carbide‐free lath microstructure (martensite and bainite), and retained austenite up to 12% are obtained which may be due to combined addition of Si and Al. The attractive combination of yield strength (575–699 MPa), tensile strength (1252–1262 MPa), and total elongation (14–16%), as well as continuous yielding behavior, are suitable for structural and automotive applications.