摘要
贝氏体微合金钢在火灾等热扰动下更易由非平衡组织向平衡组织转变,造成材料性能下降,引发安全风险。本文采用不同回火工艺模拟不同热扰动行为,采用硬度测试、金相观察、扫描电子显微分析等手段,对低碳铌微合金钢在不同回火工艺下的组织性能转变进行讨论,揭示热扰动过程中的组织性能转变规律。结果表明,在700℃和600℃下回火的硬度变化规律基本相同,都存在硬度快速下降、缓慢下降、二次快速下降及最终稳定四个阶段。分别对应位错回复及M-A岛分解、板条贝氏体板条特征退化及贝氏体铁素体晶界迁移、贝氏体铁素体再结晶及富锰第二相形核,以及再结晶贝氏体铁素体和富锰第二相长大四个阶段。该研究为铌微合金钢在高温热扰动下的失效行为提供参考。
Under thermal disturbance such as fire,bainite microalloy steel is more likely to change from non-equilib-rium to equilibrium structure,resulting in decline in material properties and safety risks.In this paper,different tempering processes were used to simulate different thermal disturbance behaviors.The microstructure and proper-ties transformation of low carbon niobium microalloyed steel under different tempering processes was discussed by means of hardness test,metallographic observation and scanning electron microscopy analysis.The law of micro-structure and properties transformation during thermal disturbance was revealed.The results showed that the hard-ness change law of tempering at 700℃ and 600℃ wasbasically thesame,and therewerefour stagesofhardness:rapid decrease,slow decrease,secondary rapid decrease and final stability.They correspond to four stages:disloca-tion recovery and M-A island decomposition,lath bainite lath characteristic degradation and bainite ferrite grain boundary migration,bainite ferrite recrystallization and manganese-rich second phase nucleation,and recrystallized bainite ferrite and manganese-rich second phase growth.This study provided a reference for the failure behavior of niobium microalloyed steel under high temperature thermal disturbance.
作者
顾小阳
曳彦奇
GU Xiaoyang;YE Yanqi(Wide Plate Plan of Nanjing Iron and Steel Co.,Ltd.,Nanjing 210035,Jiangsu,China;State Key Laboratory of Digital Steel,Northeastern University,Shenyang 110819,Liaoning,China)
出处
《四川冶金》
2025年第4期50-54,共5页
Sichuan Metallurgy
关键词
铌微合金钢
热扰动
贝氏体
高温回火
组织性能
niobium microalloyed steel
thermal disturbance
bainite
high temperature tempering
microstructure and properties
