铁路车辆用V-N-Cr微合金化Q690高强耐候钢组织性能和腐蚀行为

Microstructure and corrosion behavior of V-N-Cr microalloyed Q690 high strength weathering steel for railway vehicles

为开发新一代铁路车辆用高强耐候钢,采用两阶段轧制制备V-N-Cr微合金化Q690耐候钢,并进行组织观察和力学性能检测。采用周期浸润腐蚀实验对V-N-Cr微合金化Q690耐候钢与Q345钢进行腐蚀行为研究。结果表明:V-N-Cr微合金化Q690耐候钢的显微组织为多边形铁素体、针状铁素体、板条贝氏体以及少量的M/A岛,屈服强度及抗拉强度分别为695 MPa和815 MPa,冲击性能优异,通过大小角度晶界共同作用,有效阻碍裂纹扩展。两种钢的表面均生成了明显的锈层,腐蚀产物主要包含α-FeOOH,β-FeOOH,γ-FeOOH和Fe_(3)O_(4)。腐蚀360 h后Q345钢的平均腐蚀失重速率为1.83 g/(h·cm^(2)),V-N-Cr耐候钢的腐蚀失重速率为0.96 g/(h·cm^(2)),显著低于Q345钢。

In order to develop a new generation of high strength weathering steel for railway vehicle,V-N-Cr microalloyed Q690 weathering steel was produced by two-stage rolling,and the microstructures and mechanical properties were studied.The corrosion behavior of V-N-Cr microalloyed Q690 weathering steel and Q345 steel was studied by cyclic wet/dry corrosion tests.The results show that the microstructure of V-N-Cr microalloyed Q690 weathering steel is polygonal ferrite,acicular ferrite,lath bainite and a few M/A phase.The yield strength and tensile strength are 695 MPa and 815 MPa,respectively,with excellent impact performance.The crack propagation is effectively hindered by the interaction of grain boundaries with large and small angles.The surfaces of both kinds of steels have formed rust layer,and corrosion products mainly includeα-FeOOH,β-FeOOH,γ-FeOOH and Fe_(3)O_(4).After 360 h corrosion,the average corrosion rate of Q345 steel is 1.83 g/(h·cm^(2)),and that of V-N-Cr weathering steel is 0.96 g/(h·cm^(2)).