终冷温度对Q345R钢组织及性能的影响

对压力容器用钢Q345R开展终冷试验,研究终冷温度对轧态及正火态钢板力学性能与显微组织的影响。结果表明,在不同终冷温度下,轧态及正火态Q345R钢的力学性能均满足标准要求,但轧后直接空冷时,性能余量较小,在终冷温度为650 ℃时,力学性能较好;随着终冷温度的升高,钢板的屈服强度、抗拉强度、冲击性能均有下降的趋势,组织逐渐变粗大;轧态及正火态试样的微观组织均为典型的铁素体+珠光体,与热轧态钢板相比,正火态钢板的屈服强度和抗拉强度均明显降低,但冲击性能显著提高,且正火后组织有所细化。

Effect of final cooling temperature on microstructure and properties of Q345R steel

Final cooling test was carried out on the pressure vessel steel Q345R, and the effect of final cooling temperature on mechanical properties and microstructure of the as-rolled and normalized steel plate was studied. The results show that the mechanical properties of the as-rolled and normalized Q345R steel at different final cooling temperatures meet the standard requirements, but when directy air cooled after rolling, the performance margin is small. When the final cooling temperature is 650 ℃, the mechanical properties are relatively better. With the increase of final cooling temperature, the yield strength, tensile strength, and impact property of the steel plate have a downward trend, and the microstructure gradually becomes coarser. The microstructure of the as-rolled and normalized specimens are all typical ferrite+pearlite, and after normalization of the steel plate, the yield strength and tensile strength are significantly lower than that of the hot-rolled steel plate, while the impact property is significantly improved, and the microstructure becomes finer.