高温水冷却后Q355钢材力学性能试验研究  

EXPERIMENTAL RESEARCH ON MECHANICAL PROPERTIES OF WATER-COOLED Q355 STEEL AFTER BEING SUBJECTED TO HIGH TEMPERATURE

作　　者：杨财骏 张春涛[1] YANG Caijun;ZHANG Chuntao(School of Civil Engineering and Architecture,Southwest University of Science and Technology,Mianyang 621010,China)

机构地区：[1]西南科技大学土木工程与建筑学院,四川绵阳621010

出　　处：《工业建筑》2021年第11期165-170,38,共7页Industrial Construction

基　　金：2020年大学生创新创业训练计划项目(S202010619026)。

摘　　要：自2019年2月1日起,GB/T 1591—2018《低合金高强度结构钢》要求将原有的Q345钢更换为Q355钢,而火灾后钢材的残余力学性能是火灾后安全评价的关键指标。水冷却作为火灾中广泛应用的灭火方式,在大多数情况下是最为快速且高效的。因此,对高温浸水冷却后国产Q355钢材试件进行了单轴拉伸试验,获得高温水冷却后Q355钢材的应力-应变曲线和相关力学性能参数,并分析钢材高温后残余力学性能随温度的变化规律。此外,还对比分析了Q355钢材与Q235、Q460和Q690钢材高温后力学性能的差异。结果表明:受热温度低于600℃时,Q355钢材力学参数变化相对较小,屈服强度和弹性模量的变化幅度均未超过10%;温度超过600℃后,Q355钢材经浸水冷却后屈服强度和极限强度随温度升高而增大,弹性模量和伸长率却随温度的升高而降低;高温冷却后,Q355与Q235、Q460和Q690钢材的力学性能变化规律相似,但具体变化幅度却存在差异。最后,基于试验结果,建立了Q355钢材在水冷却方式下各力学参数随温度变化的数学模型,利用该模型可对火灾后Q355钢材的力学性能进行有效评估。The Chinese National Standard High Strength Low Alloy Structural Steels(GB/T 1591-2018) requires that Q345 steel must be replaced by Q355 steel from February 1, 2019. Its residual mechanical properties after a fire are the key indicators for post-fire safety evaluation. As a widely-used fire extinguishing method in fire, water cooling is the fastest and most efficient firefighting method. Therefore, a uniaxial tensile test was conducted on the domestic Q355 steel specimens after water cooling from high temperature. The stress-strain curves and related mechanical properties of Q355 steel after water cooling from high temperature were obtained, and the variations of the residual mechanical properties of Q355 steel after water cooling high temperature were analyzed. The differences in mechanical properties of Q355 steel and Q235, Q460 and Q690 steels after cooling from high temperatures were also compared and analyzed. The results showed that when the heating temperature was lower than 600 ℃, the mechanical properties of Q355 steel had relatively small changes, and the maximum changes in yield strength and elastic modulus did not exceed 10%. When the temperature exceeded 600 ℃, the yield strength of Q355 steel after being immersed in water was cooled. And the ultimate strength increased with the increase of temperature, but the elongation decreased with the increase of temperature. After cooling from high temperatures, the Q355 steel had similar changes with Q235, Q460 and Q690 steels in mechanical properties, but the specific change range had differences. Finally, based on the test results, a mathematical model of the change in mechanical parameters of Q355 steel cooled by water was established. This model could be used to effectively evaluate the mechanical properties of Q355 steel after fire.

关 键 词：Q355钢材 高温 力学性能 浸水冷却 数学模型 

分 类 号：TU511.3[建筑科学—建筑技术科学]