MICROSTRUCTURE AND MECHANICAL PROPERTIES OF Nb MICROALLOYED Q370qE-HPS BRIDGE STEEL PRODUCED BY TMCP
A high-performance Q370qE-HPS bridge steel with low carbon content(≤0.10wt%),Nb microalloying(0.025-0.050wt%)and low carbon equivalent(CEV)(≤0.38%)has been produced using TMCP procedure.The microstructure and mechanical properties of typical steel plates and layers parallel to rolling surface were characterized.The results show that the microstructure consists of fine-grained quasi-polygonal ferrite(QPF),less pearlite and a large number of fine dispersed Nb-rich precipitates.Consequently,an excellent combination of high strength,high toughness and low yield-to-tensile strength ratio(YR)is obtained.In addition,the QPF grain refinement and pearlite reduction take place simultaneously with increasing distance from central to surface of an identical plate or decreasing thickness of plate,leading to increase in yield strength(Rp0.2),impact energy(EKV2,-40℃)and YR,and approximately the same tensile strength(Rm).The effect of QPF grain size on Rp0.2 and effects of QPF grain size and pearlite area fraction on EKV2(-40℃)can be described by Hall-Petch formula and Boltzmann model,respectively,while the YR is in a good linear relation to QPF grain size and pearlite area fraction.
Nb microalloying Bridge steel TMCP Microstructure Mechanical properties
Xi Tian Qingfeng Wang Hongyan Sun Ming Li Zhibin Fu Jun Hong Houxin Wang Aimin Guo
State Key Laboratory of Metastable Materials Science and Technology,Yanshan University,No. 438 Hebei State Key Laboratory of Metastable Materials Science and Technology,Yanshan University,No. 438 Hebei Nanjing Iron and Steel Company Limited,Xie Jiadian,Luhe District,Nanjing,Jiangsu Province,210035,Chi CITIC-CBMM Microalloying Technology Center,No. 6 Xinyuan South Road,Chaoyang District,Beijing,100004
国内会议
杭州
英文
947-954
2015-11-11（万方平台首次上网日期，不代表论文的发表时间）