PDF《高温下与高温后 Q550D 高强钢材料力学性能试验》

第52 卷第7期2019 年7月天津大学学报(自然科学与工程技术版) Journal of Tianjin University(Science and Technology) Vol.

52 No.

7 Jul.

2019 收稿日期:2018-09-11;

修回日期:2018-12-10. 作者简介:范圣刚(1974― ) ,男,博士,教授. 通信作者:范圣刚,101010393@seu.edu.cn. 基金项目:国家自然科学基金资助项目(51878146,51378105);

江苏省 青蓝工程 中青年学术带头人资助项目(2016);

江苏省 六 大人才高峰 高层次人才选拔培养资助项目(JZ-001). Supported by the National Natural Science Foundation of China(No. 51878146,No. 51378105),the Jiangsu Provincial Qing Lan Project (2016),the Jiangsu Provincial Six Talent Peaks(No. JZ-001). DOI:10.11784/tdxbz201809030 高温下与高温后 Q550D 高强钢材料力学性能试验 范圣刚 1,

2 ,刘平2,石 可2,肖韩杰

2 ,钱峰2,方 超2(1. 东南大学混凝土及预应力混凝土结构教育部重点实验室,南京 210096;

2. 东南大学土木工程学院,南京 210096) 摘要:高强钢具有强度高、韧性好、可焊性优良等优点,其在土木工程中的应用越来越广泛.高强钢在火灾下的 力学性能是钢结构抗火设计的重要影响因素.为获取高温下与高温后 Q550D 高强钢材料的力学性能,基于稳态试 验方法,对Q550D 高强钢开展了拉伸试验,考察了不同冷却方式(自然冷却与浸水冷却)与过火温度对 Q550D 高强 钢力学性能的影响,获取了不同温度工况下 Q550D 高强钢的应力-应变曲线和高温下与高温后各项力学性能参数指 标(弹性模量、屈服强度、抗拉强度和极限伸长率)的折减系数,并将试验结果与已有规范和文献结果进行了对比分 析.结果表明:高温下 Q550D 高强钢的弹性模量、屈服强度、抗拉强度随着试验温度的升高而逐渐下降,其折减 系数均低于各国规范的取值;

当温度超过

400 ℃时,高温下 Q550D 高强钢的弹性模量、屈服强度和抗拉强度下降 明显,当温度超过

700 ℃时,3 个力学性能指标均接近于零;

不同冷却方式与过火温度对 Q550D 高强钢的弹性模量 影响不大;

当温度低于

600 ℃时,高温冷却后 Q550D 高强钢的屈服强度和抗拉强度的折减并不明显,当温度超过

600 ℃时,屈服强度和抗拉强度显著下降,且自然冷却方式下的下降程度更大;

高强钢与普通钢高温冷却后的屈服 强度与抗拉强度存在较大差别. 关键词:高强钢;

力学性能;

稳态试验;

高温冷却;

折减系数 中图分类号:TU391.1 文献标志码:A 文章编号:0493-2137(2019)07-0680-10 Experiment on Mechanical Properties of Q550D High-Strength Steel Exposed to Overall Stage of Fire Exposure Fan Shenggang1,

2 ,Liu Ping2 ,Shi Ke2 ,Xiao Hanjie2 ,Qian Feng2 ,Fang Chao2 (1. Key Laboratory of Concrete and Prestressed Concrete Structures of Ministry of Education, Southeast University,Nanjing 210096,China;

2. School of Civil Engineering,Southeast University,Nanjing 210096,China) Abstract:High-strength steels are widely used in civil engineering because of their high strength,good toughness, and excellent weldability. Their mechanical properties in fire are critical influence factors on the fire resistance design of steel structures. To investigate mechanical properties of Q550D high-strength steel at elevated temperatures and after cooling from elevated temperatures,tensile tests based on steady-state test technique were conducted, including steady-state method and post-fire tensile tests. Influences of different cooling conditions(natural cooling and water cooling)and various temperatures on the mechanical properties of Q550D high-strength steel were investigated. Stress-strain curves and reduction factors of mechanical performance indexes(elastic modulus,yield strength, tensile strength and elongation)at different temperatures were obtained. Test results were compared with those of simi- lar studies and design standards of various countries. The results showed that with the increase of test temperatures, elastic modulus,yield strength and tensile strength of Q550D high-strength steel gradually decreased at elevated tem-