摘要
本研究设计了4组Nb添加量依次为0、0.025%、0.085%、0.180%的低合金高强钢,通过OM、SEM/EDS和力学性能测试,研究了Nb微合金钢的微观组织和强韧化机制。结果表明,未添加Nb的钢组织由粗大的多边形铁素体和少量贝氏体组成,而Nb微合金钢组织主要由细小的针状铁素体和贝氏体构成,且随着Nb含量的增加,析出相NbC的数量增多,晶粒逐渐细化。当Nb含量为0.085%时,钢具有最佳的综合力学性能,这可以归因于硬质相贝氏体以及细小的晶粒所带来的细晶强化作用,另一方面,弥散分布的细小析出相NbC(尺寸分布在50~300 nm)保证了钢的组织均匀性,0.085%Nb钢表现出最为稳定的低温冲击韧性。
In this study,four groups of high-strength low-alloy(HSLA)steels with Nb addition of 0,0.025%,0.085%,and 0.180%,respectively,were designed.OM,SEM/EDS and mechanical property tests were employed to investigate the microstructure and strength-toughening mechanisms of Nb micro-alloyed steels.The results show that the steel without Nb addition primarily consists of coarse polygonal ferrite and a small amount of bainite,while the microstructure of Nb micro-alloyed steel is predominantly composed of fine acicular ferrite and bainite.As the Nb content increases,the number of NbC precipitates increases,and the grains gradually refine.The steel with 0.085%Nb exhibits the optimal comprehensive mechanical properties,which can be attributed to the hardening effect of bainitic phase and grain refinement due to fine grains.On the other hand,the fine and uniformly disper-sed NbC precipitates(with a size distribution between 50 nm and 300 nm)ensure the homogeneity of the steel microstructure.Consequently,the steel with 0.085%Nb demonstrates the most stable low-temperature impact toughness.
作者
林轩艺
王红鸿
鄢文泽
Lin Xuanyi;Wang Honghong;Yan Wenze(State Key Laboratory of Refractories and Metallurgy,Wuhan University of Science and Technology,Wuhan 430081,China)
出处
《武汉科技大学学报》
CAS
北大核心
2023年第3期175-179,共5页
Journal of Wuhan University of Science and Technology
基金
国家自然科学基金面上项目(51971165).
关键词
NB微合金化
低合金高强钢
NB含量
细晶强化
NBC
低温冲击韧性
Nb micro-alloying
HSLA steel
Nb content
grain refinement strengthening
NbC
low-temperature impact toughness
作者简介
林轩艺(1999-),男,武汉科技大学硕士生.E-mail:1395244242@qq.com;通讯作者:王红鸿(1967-),女,武汉科技大学教授,博士生导师.E-mail:wanghonghong@wust.edu.cn。
