桥梁钢Q345qD低温力学性能及冲击韧性试验研究  

EXPERIMENTAL RESEARCH ON MECHANICAL PROPERTIES AND IMPACT TOUGHNESS OF BRIDGE STEEL Q345qD AT LOW TEMPERATURE

作　　者：贾单锋 王元清[2] 崔佳[1] 廖小伟[2] 石永久[2] Jia Danfeng Wang Yuanqing Cui Jia Liao Xiaowei Shi Yongjiu(School of Civil Engineering, Chongqing University, Chongqing 400045, China Key Laboratory of Civil Engineering Safety and Durability of China Education Ministry, Department of Civil Engineering, Tsinghua University, Beijing 100084, China)

机构地区：[1]重庆大学土木工程学院,重庆400045 [2]清华大学土木工程安全与耐久教育部重点实验室,北京100084

出　　处：《钢结构》2017年第5期41-45,共5页Steel Construction

基　　金：国家自然科学基金项目(51378289;51678339);高等学校博士学科点专项科研基金项目(20130002110085)

摘　　要：为了研究低温环境中桥梁钢Q345qD的力学性能和冲击韧性,防止钢结构桥梁在低温环境中发生脆性断裂,选取钢桥服役环境中可能出现的5个温度点(+20,0,-20,-40,-60℃)进行了系统的低温静力拉伸试验和V形缺口冲击试验,并与文献数据进行对比分析,得到了强度、塑性及冲击韧性指标随温度变化的规律及拟合曲线。研究结果表明:桥梁钢Q345qD抗低温冷脆性能较好,低温下力学性能及冲击韧性均满足防断要求;随着温度的下降,屈服强度及抗拉强度均有所提高,断后伸长率、断面收缩率和弹性模量没有明显变化,冲击韧性下降;在研究温度区间内,相比于相同屈服强度的Q345系列钢材,Q345qD冲击功Boltzmann拟合曲线有较高的上、下平台能,不易发生脆性转变,能够满足常规钢结构桥梁的低温防断需求。In order to prevent the brittle fracture at low temperature of steel bridge,it is significant to obtain the mechanical properties and impact toughness of the most widely used bridge steel Q345qD. A series of static tensile tests and V-notch impact tests were conducted systematically at the temperature of ＋20,0,-20,-40,-60℃ which were compared with experimental results from the literature. The variation regulation of strength,plasticity and impact toughness and their fitting curves were obtained. The results indicated that Q345qD had favorable low temperature performance,and the mechanical properties and impact toughness at low temperature could meet the requirements of national regulation. With the decline of environment temperature,yield strength and tensile strength of base steel increased a little. There was no variation in elongation of rupture,reduction of area and Young’s modulus while the impact toughness decreased a lot as the environment temperature declining. Based on the impact energy within the temperature range,the Boltzmann curve of Q345qD had higher lower-platform energy and upper-platform energy than other Q345 steel with same yield strength. The bridge steel Q345qD can meet the anti-fracture requirements of steel bridges at low temperature.

关 键 词：低温 桥梁钢 力学性能 冲击韧性 防断设计 

分 类 号：U444[建筑科学—桥梁与隧道工程]