摘要
采用扫描电镜(SEM)、电子背散射衍射(EBSD)技术和室温拉伸测试等研究了Nb、V、Ti微合金化元素对20MnSi钢显微组织和力学性能的影响。结果表明:Nb、V、Ti微合金化及其所形成的第二相粒子可以阻碍试验钢的晶界迁移、细化晶粒尺寸,经热轧-空冷后晶粒明显细化,晶粒尺寸可达12级,综合力学性能明显优于20MnSi穿水钢筋,并达到新国标中400 MPa级钢筋所要求的性能指标。根据理论模型计算,晶界强化、固溶强化和位错强化增量分别约占屈服强度的54%、22%和17%,而由于微合金化元素含量较低且所形成的第二相粒子体积分数较低,析出强化增量在试验钢屈服强度中的占比仅约7%,表明Nb、V、Ti微合金化设计而导致的晶粒细化对试验钢力学性能提升所产生的贡献十分显著。
Effect of Nb,V and Ti microalloying elements on microstructure and mechanical properties of 20MnSi steel was studied by means of scanning electron microscopy(SEM),electron backscatter diffraction(EBSD)technique and room temperature tensile testing.The results show that the microalloying of Nb,V,Ti and the formed second phase particles can hinder the grain boundary migration and refine the grain size of the experimental steel.After hot rolling and air cooling,the grain size is significantly refined,reaching a level of Grade 12.The comprehensive mechanical properties of the experimental steel are significantly better than those of the 20MnSi water quenching steel bars,and meet the performance indicators required by the new national standard for 400 MPa grade steel bars.According to theoretical model calculations,the increments of grain boundary strengthening,solid solution strengthening and dislocation strengthening account for about 54%,22% and 17% of the yield strength,respectively.However,due to the low content of microalloying elements and the low volume fraction of the formed second phase particles,the precipitation strengthening increment accounts for only about 7% of the yield strength of the experimental steel,indicating that the grain refinement caused by the design of Nb,V and Ti microalloying contributes significantly to the improvement of the mechanical properties of the experimental steel.
作者
蒲春雷
姜嫄
闫洞旭
方实年
丁汉林
朱国辉
PU Chun-lei;JIANG Yuan;YAN Dong-xu;FANG Shi-nian;DING Han-lin;ZHU Guo-hui(Department of Intelligent Development,MCC Huatian Engineering and Technology Corporation,Nanjing 210019,China;School of Iron and Steel,Soochow University,Suzhou 215137,China;School of Metallurgical Engineering,Anhui University of Technology,Maanshan 243002,China)
出处
《材料热处理学报》
CAS
CSCD
北大核心
2023年第7期99-106,共8页
Transactions of Materials and Heat Treatment
基金
国家自然科学基金(52174367)
安徽省重点研究和开发计划项目(201904a05020008)。
