轧制工艺参数对Q345建筑钢组织和强度的影响

Effect of Rolling Process Parameters on Microstructure and Strength of Q345 Construction Steel

采用不同的TMCP工艺,轧制了16mm厚的Q345建筑钢板材。对钢材的金相组织进行了观察,对抗拉强度和屈服强度进行了测试。结果表明,随着精轧温度区间向较低的轧制温度推移时,钢材F+P(铁素体+珠光体)组织明显细化,抗拉强度和屈服强度均逐渐升高,屈强比小幅增加;随着冷却速度的增加,组织由F+P逐渐向F+B(铁素体+贝氏体)转变,抗拉强度和屈服强度均逐渐升高,屈强比明显增加,特别是当冷却速度超过40℃/s时屈强比大幅提高;随着终冷温度的增加,F组织尺寸增大,P含量降低,抗拉强度和屈服强度均线性降低,屈强比也几乎呈线性降低的趋势。

Q345 construction steel plates with 16 mm thickness of were rolled by using TMCP technology.The tensile strength and yield strength of the steel were tested and the metallographic microstructures were observed. The results show that, as the finishing temperature interval goes to the lower temperature, F＋P microstructure of the steel is refined, the tensile strength and yield strength increase gradually, and the yield strength ratio slightly increases; with the increase of cooling rate,the microstructure transforms from P＋F to P＋B, the tensile strength and yield strength increase, and the yield strength ratio increases significantly, which increases dramatically especially when the cooling rate is more than 40 ℃/s; with the increase of final cooling temperature, the F size increases and the P content decreases, the tensile strength and yield strength decreases linearly, and the yield strength ratio decreases almost linearly.