This article reports a new generation of Q460 multi-functional construction structural steel,which has high strength(yield strength larger than 460 MPa),excellent toughness(higher than 110 J/cm2 at-60℃),lower yield ratio(lower than 0.8),good fire resistance(yield strength at 600℃ larger than two-thirds of its room-temperature yield strength)and better cor-rosion resistance.The effects of finish cooling temperature(FCT)on the microstructure and properties were studied by scanning electron microscopy(SEM),transmission electron microscopy(TEM),emission electron probe micro-analysis(EPMA),electron backscattering diffraction(EBSD),tensile tester,impact tester,periodic immersion cycle acceleration test and electrochemical experiment.The results show that the strength and toughness are simultaneously improved by decreasing the FCT due to more lath-like bainite with large number of dislocations,refined martensite/austenite(M/A)with higher carbon concentration and increased high angle boundaries.In addition,the fire resistance of the newly developed Q460 steel is obviously better than the conventional one,which is mainly due to non-recrystallized lath-like bainite with high dislocation density at elevated temperature.The corrosion resistance of the new Q460 steel is also improved due to the addition of Cu and Cr.

Zhenye Chen;Zhangguo Lin;Jianjun Qi;Yang Feng;Liqing Chen;Guodong Wang

State Key Laboratory of Rolling and Automation,Northeastern University,Shenyang 110819,China;User Technology Department,Technology Research Institute of HBIS,Shijiazhuang 050000,China

金属学报（英文版）

[1]Zhenye Chen;Zhangguo Lin;Jianjun Qi;Yang Feng;Liqing Chen;Guodong Wang-.Microstructures and Mechanical Properties of a New Multi-functional 460 MPa Grade Construction Structural Steel)[J].金属学报（英文版）,2022(07):1131-1142

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