高强度Q460钢焊接截面高温作用后残余应力

Residual Stress in Welded High Strength Q460 Steel Sections After Fire Exposure

摘要:

为了得到高温作用对高强度Q460钢焊接截面残余应力的影响，采用电炉对高强度Q460钢焊接H形和箱形截面构件进行升温后自然降温.采用切条法测试构件降温后残余应力的分布作为对比，测试了未升温试件的残余应力.试验得到了高温后焊接H形和箱形截面残余应力数值和不同温度后残余应力降低系数.采用有限元软件ANSYS分析了残余应力的降低对高温下Q460钢柱承载力的影响.研究表明：高温作用对焊接残余应力影响较大，升温温度越高，残余应力降低越大.残余应力的降低对高温下Q460钢柱的承载力产生明显影响，与不考虑残余应力变化相比，钢柱的承载力设计值可提高10%左右.

Abstract:

In order to obtain the effect of temperature on the residual stress in welded high strength Q460 steel sections, the Hsection and boxsection Q460 steel members were heated by using electric furnace and then cooled naturally to room temperature. The residual stresses were measured by using the sectioning method after the steel member cooling. For comparison, the residual stress in the steel member without heating was also tested. The magnitude of residual stresses after being exposed to high temperature were obtained as well as the reduction factor of residual stress exposed to various temperatures. The effect of reduction in residual stress on the load bearing capacity of Q460 steel columns at elevated temperature were analyzed by employing ANSYS. The study shows that temperature has a great influence on welded residual stress. As the temperature increases, the residual stress is more reduced. The reduction of residual stress has a significantly effect on the load bearing capacity of Q460 steel columns in fire, and the design value of load bearing capacity can be enhanced by 10% in comparison with the load bearing capacity without considering the residual stress variation.