泡沫灭火后Q460高强钢力学性能试验研究  

Experimental Study on Mechanical Properties of High Strength Q460 Steel After Foam Extinguishing

作　　者：陈光鹏 张春涛[1,2] CHEN Guangpeng;ZHANG Chuntao(School of Civil Engineering and Architecture,Southwest University of Science and Technology,Mianyang 621010,China;Shock and Vibration of Engineering Materials and Structures Key Laboratory of Sichuan Province,Mianyang 621010,China)

机构地区：[1]西南科技大学土木工程与建筑学院,绵阳621010 [2]工程材料与结构冲击振动四川省重点实验室,绵阳621010

出　　处：《材料导报》2021年第6期6151-6156,共6页Materials Reports

基　　金：国家自然科学基金(51508482);全国大学生创新创业训练计划(S202010619026);西南科技大学研究生创新基金(20ycx0044)。

摘　　要：对室温及200~900℃高温自然冷却和泡沫灭火冷却后的Q460高强钢开展静力拉伸试验研究,获得高温及不同冷却方式后Q460高强钢的力学性能参数,并与Q235和Q690钢高温后力学性能变化规律进行对比分析,建立Q460高强钢力学性能参数随温度和冷却方式变化的数学模型。结果表明:Q460高强钢在不同温度和冷却方式下呈现不同的表观特征;温度和冷却方式对弹性模量的影响较小,却对Q460高强钢的强度和伸长率有较大影响,温度低于500℃时,Q460高强钢高温冷却后的强度和伸长率与常温时接近,但随温度的升高,强度降低而伸长率增大;温度高于500℃后,Q460高强钢自然冷却后的强度和伸长率发生明显变化,900℃时,Q460高强钢的屈服强度、极限强度和伸长率分别为常温时的38%、67%和107%;泡沫灭火冷却后Q460高强钢的力学性能参数发生明显变化的温度为600℃,900℃时Q460高强钢的屈服强度、极限强度和伸长率分别为常温时的39%、67%和131%。基于试验数据,建立了不同冷却方式下Q460高强钢的力学性能参数随温度变化的数学模型,可对火灾后Q460高强钢的力学性能进行有效评估。High strength Q460 steel is extensively used in building construction due to its potential benefits over high strength and cost efficiency.Its performance in fire is very important to assess the extent of its fire damage and reusability.This paper presents the details of an experimental investigation on the post-fire mechanical properties of high strength Q460 steel after air and firefighting foam cooling.Tensile tests are performed on specimens exposed to elevated temperatures varying from 200℃to 900℃and then cooled down to room temperature in air or in extinguisher foam.The results from this investigation provided post-fire stress-strain curves,yield strengths,ultimate strength,elastic modulus,ultimate elongation and their residual factors.Systematic comparative analysis for the differences of mechanical properties of Q460,Q690 and Q235 steels are carried out.Significant differences are observed on the surface after exposing different high temperature and cooling in various media.The inf-luence of high temperature and cooling methods on elastic modulus is negligible,while sharp reduction is especially noted in the yield strength,ultimate strength and ultimate elongation.In addition,it is found that the loss of mechanical properties of Q460 steel is negligible for exposure tempe-rature up to 500℃and cooling in air or in extinguisher foam.When exposed to 900℃,the yield strength,ultimate strength and ultimate elongation of high strength Q460 steel cooling in air are able to retain 38%,67%and 107%of their ambient temperature capacity,whereas the yield strength,ultimate strength and ultimate elongation after foam extinguishing can retain 39%,67%and 131%of their ambient temperature capacity.Finally,predictive equations are proposed for simple evaluation of post-fire material performance of Q460 steel.The results can be used to eva-luate the mechanical performance of Q460 steel structures after fire.

关 键 词：Q460高强钢 高温 冷却方式 数学模型 

分 类 号：TU392.2[建筑科学—结构工程]