Effect of Nb on the Microstructure and Properties of Cold Rolled and Annealed Mo Microalloyed Bainitic Steel  

作　　者：Yi Zhang Guang Xu Li Wang Yaowen Xu Zhengliang Xue 

机构地区：[1]Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education,Hubei Collaborative Innovation Center for Advanced Steels,Wuhan University of Science and Technology,Wuhan 430081,China [2]State Key Laboratory of Development and Application Technology of Automotive Steels(Baosteel Group),Shanghai 201900,China

出　　处：《Journal of Harbin Institute of Technology(New Series)》2016年第4期52-58,共7页哈尔滨工业大学学报（英文版）

基　　金：Sponsored by the National Natural Science Foundation of China(Grant No.51274154);the National High Technology Research and Development Program of China(Grant No.2012AA03A504);the State Key Laboratory of Development and Application Technology of Automotive Steels(Baosteel Group);Key Project of Hubei Education Committee(Grant No.20121101)

摘　　要：Two kinds of low carbon bainitic steels,Nb-free Mo bearing and Nb + Mo addition steels,were cold rolled and annealed to investigate the effect of micro-alloying element Nb on the microstructure and properties of Mo microalloyed low carbon high strength bainitic steel. No precipitates were observed in Nb-free Mo bearing steel,whereas,two types of precipitates,i.e.,Nb( C,N) and composite( Nb,Mo)( C,N),were observed in the Nb + Mo microalloyed steel,resulting in precipitation strengthening. The strength of Mo bearing steel was improved by addition of Nb under the same annealing conditions. The grain size of Nb addition steel was almost the same as Nb-free steel. Unlike the obvious grain refinement and precipitation strengthening in hot rolling,the increase in yield strength of Nb addition steels in cold rolling and annealing mainly results from the precipitation strengthening,while the effect of grain refinement strengthening can be almost ignored.Two kinds of low carbon bainitic steels,Nb-free Mo bearing and Nb + Mo addition steels,were cold rolled and annealed to investigate the effect of micro-alloying element Nb on the microstructure and properties of Mo microalloyed low carbon high strength bainitic steel. No precipitates were observed in Nb-free Mo bearing steel,whereas,two types of precipitates,i.e.,Nb( C,N) and composite( Nb,Mo)( C,N),were observed in the Nb + Mo microalloyed steel,resulting in precipitation strengthening. The strength of Mo bearing steel was improved by addition of Nb under the same annealing conditions. The grain size of Nb addition steel was almost the same as Nb-free steel. Unlike the obvious grain refinement and precipitation strengthening in hot rolling,the increase in yield strength of Nb addition steels in cold rolling and annealing mainly results from the precipitation strengthening,while the effect of grain refinement strengthening can be almost ignored.

关 键 词：RECRYSTALLIZATION ANNEALING low carbon bainitic steel NB MO cold ROLLING 

分 类 号：TG113.11[金属学及工艺—物理冶金] TG156.1[金属学及工艺—金属学]