Effect of different N and Si contents on microstructures and properties of HRB400e steel containing vanadium  

作　　者：Qian Xu Dong-ping Zhan Wei-li Xu Fu-hua Fan Hong-tao Li Huai-zhu Li Shang-kun Wang 

机构地区：[1]School of Metallurgy,Northeastern University,Shenyang,110819,Liaoning,China [2]Jianlong Xilin Steel Co.,Ltd.,Yichun,153026,Heilongjiang,China

出　　处：《Journal of Iron and Steel Research International》2025年第2期452-465,共14页钢铁研究学报(英文版)

基　　金：support from the Open Competition Scientific and Technological Research Projects of Heilongjiang Province(2022ZXJ03A02);Key Research and Development Project of School-local Cooperation in Lvliang City(No.2023XDHZ05).

摘　　要：By increasing the nitrogen content in vanadium-containing steel,the mechanical properties of the steel can be effectively improved.In order to better utilize the strengthening effect of N in vanadium-containing steel and reduce the use of ferrosilicon,which will reduce production costs and provide a theoretical basis for adjusting the composition of steel bars,we designed three different vanadium-containing steel samples with varying N and Si contents.Through mechanical property testing,metallographic microscopy,scanning electron microscopy,transmission electron microscopy,and other test methods,the evolution of the structure and mechanical properties of HRB400e steel under different N and Si contents were studied.The results showed that increasing the nitrogen content in steel can improve the yield strength of threaded steel.Before nitrogen addition,the yield strength of S1 steel exceeds the national standard at 29 MPa.After increasing the N content by 0.0056%,the yield strength of the steel exceeds the national standard of 64.4 MPa.Thermodynamic calculations revealed the presence of VN,V(C,N),Si_(3)N_(4),Fe_(3)C,and M_(7)C_(3)phases in the steel,and VN,Fe_(3)C,and M_(7)C_(3)phases were found in the test steel through the transmission electron microscope and high resolution transmission electron microscope.Increasing the N content can also increase the precipitation temperature of the precipitates,allowing them to better anchor the austenite grain boundaries during hot rolling and prevent the growth of austenite grains.This conclusion was also confirmed through high-temperature coagulation experiments.After refinement of the austenite grain size,the final ferrite and pearlite structure is further refined,and their distribution becomes more uniform.

关 键 词：Vanadium-nitrogen microalloying Ultra-high strength rebar Precipitation strengthening Grain refinement strengthening 

分 类 号：TG1[金属学及工艺—金属学]