EH32钢在人工海水中的流动加速腐蚀行为研究

目的 明晰流场、传质和锈层在EH32钢流动加速腐蚀过程中的协同作用机理。方法 利用射流喷射系统研究EH32钢的流动加速腐蚀行为，并基于CFD仿真模拟流场分布情况，最后通过微观形貌表征分析EH32钢的腐蚀形貌。结果 在射流喷射系统中，试样表面的流场分布不均匀，根据锈层的颜色可分为不同区域，喷嘴正对区域锈层最厚，但疏松多孔，形成凹坑，腐蚀最严重。远离喷嘴区域锈层逐渐减薄，但更致密，腐蚀形貌转变为“flow mark”和点蚀。结论 流场严重影响着腐蚀产物的分布，正应力高、剪切应力低的区域形成的锈层厚且疏松多孔，正应力低、剪切应力高的区域形成的锈层薄，但更致密。反应生成的阳极液随流体的转移过程导致了“flowmark”损伤形貌的形成，致密的锈层抑制了阳极液的转移，导致了点蚀坑的损伤形貌。锈层和阳极液的累积使得喷嘴中心区域表现为主要阳极区，腐蚀损伤最为严重，而远离中心区域由于致密的腐蚀产物抑制了传质过程，腐蚀速率较低。流场、锈层以及传质三者的协同作用决定了流动加速腐蚀行为。

Flow Accelerated Corrosion Behavior of EH32 Steel in Artificial Seawater

The work aims to clarify the synergistic mechanism of flow field, mass transfer and rust layer in the flow accelerated corrosion process of EH32 steel. The flow accelerated corrosion behavior of EH32 steel was studied by the jet injection system, and the flow field distribution was simulated based on CFD simulation. Finally, the corrosion morphology of EH32 steel was analyzed by microscopic morphology characterization. The result showed that in the jet injection system, the flow field distribution on the surface of the sample was uneven and could be divided into different areas according to the color of the rust layer. In the area facing the nozzle, the rust layer was the thickest but loose and porous, and the corrosion was the most serious and pits were formed. In the area away from the nozzle, the rust layer was gradually thinner but denser, and the corrosion morphology was transformed into "flow mark" and pitting. The conclusion is that the flow field seriously affects the distribution of corrosion products. The rust layer formed in the region with high normal stress and low shear stress is thick and loose, and the rust layer formed in the region with low normal stress and high shear stress is thinner but denser. The transfer process of the anodic solution generated by the reaction with the fluid leads to the formation of the "flow mark" damage morphology, and the dense rust layer inhibits the transfer of the anodic solution, resulting in the damage morphology of pitting pits. The accumulation of the rust layer and anodic liquid makes the central area of the nozzle appear as the main anode area, and the corrosion damage is the most serious, while the area away from the center has a low corrosion rate because the dense corrosion products inhibit the mass transfer process. The synergistic action of flow field, rust layer and mass transfer determines the flow accelerated corrosion behavior.