Research on mechanical properties of Q550D high-strength structural steel during heating and cooling stages of fire
To study the mechanical properties of high-strength structural steel in fire,this paper investigated the mechanical properties of domestic Q550D high-strength structural steel during the fire heating and cooling stages,including the elastic modulus,yield strength,ultimate strength,ultimate strain,and elongation at break,by using the steady state test method.A cooling stage influence coefficient was adopted to reflect differences in the mechanical properties of steel between the cooling and heating stages.The results indicate that the mechanical properties of Q550D steel at the cooling stage are related to not only the test temperature but also the peak heating temperature.When the peak heating temperature is within 600 ℃,the difference in mechanical properties between the cooling and heating stages of Q550D steel is relatively small.However,as peak heating temperature further increases,especially when peak heating temperature exceeds 700 ℃,the significant differences appear on the mechanical properties between the cooling and heating stages,the yield strength and ultimate strength decreased significantly,and the ultimate strain increases significantly.Additionally,a high-temperature mechanical property model for high-strength steel during the cooling stage was established,and the proposed formula for calculating the mechanical property parameters of Q550D steel at the fire cooling stage was fitted well.
Q550D high-strength structural steelsteady-state testcooling stageinfluence coefficienthigh-temperature mechanical performance model
万方数据
维普
