09CuPTi系耐候钢组织性能及耐腐蚀行为

Microstructure,Mechanical Property and Corrosion Behavior of 09CuPTi Series Weathering Steel

在热连轧生产线上采用两阶段轧制生产了09CuPTi系耐候钢,研究了轧制工艺参数对耐候钢板微观组织和力学性能的影响规律。结果表明,3种工艺试验钢的显微组织均为针状铁素体和贝氏体。当终冷温度为530℃冷却速度为25℃/s时,组织以更细小均匀的板条贝氏体为主,屈服强度及抗拉强度分别为617MPa和702MPa,韧脆性转变温度较低,具有良好的强韧性。对轧后钢板进行了耐腐蚀试验,研究了09CuPTi-Nb钢工艺B成品和参考钢在模拟工业大气环境下的腐蚀演化行为。结果表明,在腐蚀初期腐蚀速度随干湿循环次数的增加而增大,在后期腐蚀速度逐渐降低,09CuPTi-Nb钢的腐蚀速率与SPA-H钢相当,但低于Q345钢。09CuPTi-Nb钢锈层分为内外两层,内锈层致密主要由α-FeOOH和少量γ-Fe2O3组成,Q345钢锈层主要由α-FeOOH、γ-Fe2O3和Fe3O4组成。电化学试验表明,腐蚀产物促进阴极过程,抑制阳极过程。

09CuPTi-Nb weathering steel was produced by a two-stage roiling in a hot strip roiling production line. The influence of rolling process parameters on microstructure and mechanical properties were investigated. It shows that microstructure of three test steel is mainly acicular ferrite and bainite. When a final cooling temperature is 530 ℃ and cooling rate is 25 ℃/s, microstructure is composed of fine and homogeneous lath bainite. Yield strength and tensile strength is 617MPa and 702MPa, respectively, and ductile-brittle transition temperature is lower. At this condition the tested steel has high strength and toughness. The corrosion evolution of B sample o{ 09CuPTi Nb weathering steel and reference steels in a simulated industrial atmosphere environment was studied. It shows that the corrosion rate increases with increasing the wet / dry cycles in the initial stage of the test, however it decreases in the latter stage of the test. Corrosion rate of 09CuPTi-Nb weathering steel is near to SPA H steel and lower than that of Q345 steel. Rust layer of 09CuPTi-Nb weathering steel is divided into outer and inner layers, and inner rust layer is dense and mainly composed of ^-FeOOH and a little of y-Fe203 composition. Rust layer of Q345 steel is composed of a-FeOOH, 7-Fe203 and FeaO4 composition. The electrochemistry test indicates that the corrosion product can promote the cathodic process and restrain the anodic process.