The present article aims at elucidating the effect of thermo-mechanical controlled processing(TMCP),especially the finish cooling temperature,on microstructure and mechanical properties of high strength low alloy steels for developing superior low temperature toughness construction steel.The microstructural features were characterized by scanning electron micro-scope equipped with electron backscatter diffraction,and the mechanical behaviors in terms of tensile properties and impact toughness were analyzed in correlation with microstructural evolution.The results showed that the lower finish cooling temperature could lead to a considerable increase in impact toughness for this steel.A mixed microstructure was obtained by TMCP at lower finish cooling temperature,which contained much fine lath-like bainite with dot-shaped M/A constituent and less granular bainite and bainite ferrite.In this case,this steel possesses yield and ultimate tensile strengths of～885 MPa and 1089 MPa,respectively,and a total elongation of～15.3％,while it has a lower yield ratio of～0.81.The superior impact toughness of～89 J at-20℃was obtained,and this was resulted from the multi-phase microstructure including grain refine-ment,preferred grain boundaries misorientation,fine lath-like bainite with dot-shaped M/A constituent.

Wen-Ting Zhu;Jun-Jun Cui;Zhen-Ye Chen;Yang Zhao;Li-Qing Chen

State Key Laboratory of Rolling and Automation,Northeastern University,Shenyang 110819,China;Key Laboratory of Nuclear Materials and Safety Assessment,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China;User Technology Department,Technology Research Institute of HBIS,Shijiazhuang 050000,China;School of Materials Science and Engineering,Northeastern University,Shenyang 110819,China

金属学报（英文版）

[1]Wen-Ting Zhu;Jun-Jun Cui;Zhen-Ye Chen;Yang Zhao;Li-Qing Chen-.Correlation of Microstructure Feature with Impact Fracture Behavior in a TMCP Processed High Strength Low Alloy Construction Steel)[J].金属学报（英文版）,2022(04):527-536

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