Mn-Series Low-Carbon Air-Cooled Bainitic Steel Containing Niobium of 0.02%  

作　　者：FENG Chun FANG Hong-sheng ZHENG Yan-kang BAI Bing-zhe 

机构地区：[1]Department of Materials Science and Engineering, Tsinghua University, Beijing 100084, China

出　　处：《Journal of Iron and Steel Research International》2010年第4期53-58,共6页

基　　金：Item Sponsored by National Hi-Tech Research and Development Program of China(2007AA03Z511)

摘　　要：A new hot rolled low-carbon air-cooled bainitic steel containing Nb of 0.02% has been developed based on alloying design of the grain boundary allotriomorphic ferrite （FGBA）/granular bainite （BG） duplex steel. The as-rolled microstructure and mechanical properties of bainitie steel containing Nb of 0. 02% were investigated by tensile test, optical microscopy （OM）, scanning electron microscopy （SEM）, and transmission electron microscopy （TEM）. The results show that adding 0.02 % of Nb obviously improves the strength without sacrificing toughness of the FGBA/BG steel. Adding 0.02% of Nb not only refines the grain boundary allotriomorphic ferrite grains but also promotes the refinement of granular bainite including its bainitic ferrite and M/A island. Any Nb（C,N） has been hardly observed in the steel containing Nb of 0.02%. It is suggested that the strengthening mechanism of Nb of 0.02% can be mainly attributed to the effect of Nb in solution （solute drag-like effect） on the phase transformation rather than the precipitation strengthening of Nb（C, N） particles.A new hot rolled low-carbon air-cooled bainitic steel containing Nb of 0.02% has been developed based on alloying design of the grain boundary allotriomorphic ferrite （FGBA）/granular bainite （BG） duplex steel. The as-rolled microstructure and mechanical properties of bainitie steel containing Nb of 0. 02% were investigated by tensile test, optical microscopy （OM）, scanning electron microscopy （SEM）, and transmission electron microscopy （TEM）. The results show that adding 0.02 % of Nb obviously improves the strength without sacrificing toughness of the FGBA/BG steel. Adding 0.02% of Nb not only refines the grain boundary allotriomorphic ferrite grains but also promotes the refinement of granular bainite including its bainitic ferrite and M/A island. Any Nb（C,N） has been hardly observed in the steel containing Nb of 0.02%. It is suggested that the strengthening mechanism of Nb of 0.02% can be mainly attributed to the effect of Nb in solution （solute drag-like effect） on the phase transformation rather than the precipitation strengthening of Nb（C, N） particles.

关 键 词：low-carbon air-cooled bainitic steel NIOBIUM MICROSTRUCTURE mechanical property 

分 类 号：TG142.33[一般工业技术—材料科学与工程] U213.41[金属学及工艺—金属材料]