500MPa级高强抗震钢筋不同冷却工艺下组织和相变研究

Research on Microstructure and Phase Transformation of 500 MPa Grade Seismic Steel Bar under Different Cooling Process

以建筑结构用500 MPa级高强抗震钢筋为对象,通过热模拟实验研究了不同冷却速度和控冷终止温度对其组织和相变的影响。实验结果表明,钢筋试样心部铁素体组织的晶粒尺寸随轧后冷却速度的增加逐渐减小;钢筋试样心部贝氏体组织的含量随控冷终止温度的降低而逐渐增加,铁素体组织的晶粒尺寸在控冷终止温度为700℃时最小,此时钢筋试样心部组织的匹配性最好。

The effects of different cooling process such as cooling rate and final cooling temperature on the microstructure and phase transformation of 500 MPa grade seismic steel bar which used in building were researched through the thermal simulation experiment. The experimental results show that, the ferrite grain size of the steel bar sample in the core decreases with cooling rate increasing, the content of bainite of the steel bar sample in the core increases with controlled cooling final temperature decreasing, the core ferrite grain size is the smallest when controlled cooling final temperature is700 ℃, and the core microstructure＇s match of the steel bar sample is best.