建筑钢结构进展2025，Vol.27Issue(7)：94-107,14.DOI:10.13969/j.jzgjgjz.20240208001
火灾后低合金结构钢低周疲劳性能演化机理研究
Post-Fire Low-Cycle Fatigue Mechanism of Low-Alloy Structural Steel
摘要
Abstract
Most steel structures in high seismicity regions may continue serving after the occurrence of a non-critical fire event.In this paper,the low-cycle fatigue properties of Q345 steel after fire damage are systematically studied from macro and micro levels by the combination of experimental exploration with theoretical analysis.A total of 60 Q345 carbon steel specimens are examined,which are heated to different temperatures and cooled by different ways,followed by either incremental-amplitude cyclic loading or constant-amplitude low-cycle/extremely low-cycle fatigue loading.The typical fracture failure mechanism of the specimens is analyzed by scanning electron microscope(SEM)and metallurgical microscopy(MM).The test results show that water immersion cooling with a rapid cooling speed following a medium or large fire(heated to 750℃or 1 000℃)has a significant impact on the cyclic behavior of the Q345 steel.In these cases,the formation of martensite with high strength and poor ductility results in an increase in the cyclic stress,a decrease in the ductility and a sharp reduction of the fatigue life.These phenomena indicate that the seismic performance of steel structures may be significantly compromised after rapid cooling from a medium or large fire.Other heating-cooling processes have less pronounced effects on the hysteretic and low-cycle fatigue properties of the material.关键词
多灾害/火灾/低合金结构钢低周疲劳性能/电镜扫描/金相观察/滞回性能Key words
multi-hazard/fire/low-alloy structural steel low-cycle fatigue(LCF)performance/scanning electron microscope(SEM)/metallurgical microscopy(MM)/hysteretic behavior分类
矿业与冶金引用本文复制引用
顾跃跃,霍红伟,任海辉,郭煜斌,戴书洋,方成..火灾后低合金结构钢低周疲劳性能演化机理研究[J].建筑钢结构进展,2025,27(7):94-107,14.基金项目
国家自然科学基金(52378177,52078359),上海市"曙光计划"(22SG18) （52378177,52078359）
