碳钢及低合金钢点蚀性能的研究

选择三种典型的碳钢、低合金钢，通过极化试验比较了它们之间的点蚀诱发敏感性和模拟孔蚀的“闭塞腐蚀电池”，试验研究了它们之间的孔蚀扩展行为。结果表明，B钢的点蚀诱发能力小于A钢和C钢；在同样的阴极极化电位下，B钢的阳极溶解电流也明显小于后两者。电子探针分析了不同夹杂物在诱发点蚀过程的腐蚀特征，夹杂物是钢中主要的点蚀诱发源。显微分析“闭塞腐蚀电池”腐蚀形貌，发现腐蚀形貌具有平行沟槽状。初步分析原因是沿轧向延伸的磷偏析带及夹杂物所导致的。扫描电镜和能谱仪对腐蚀产物的形貌、成分分析结果表明：B钢的锈层均匀致密，而A钢的锈层呈网状、疏松且有大量裂纹和孔洞。

Reserch of Pitting in Carbon Steel and Low Alloy Steel

One low-carbon steel and two low-alloy steels have been selected. Their susceptibility to pitting has been compared by means of polarization test, and their behavior of pitting propagation has been studied with OCC simulation test. The results showed that the susceptibility of steel B to pitting initiation was obviously lower than steels A and C. At the same cathodic polarization potential, the anodic dissolution current of the B was smaller than A and C. Characteristic of pitting initiated by different inclusions has been studied with the EPMA, and the inclusions are the main sources of pitting corrosion. The corrosion shape of OCC was examined by means of microanalysis. It was found that parallel groove existed in corrosion shape. The extension of phosphoric segregation and inclusions along the rolling direction resulted in the corrosion shape. The SEM and EDS were used to observe the surface and the component. The results showed that the rust layer of steel B was homogeneous and dense, but the rust layer of steel A was a netlike and loose layer with a lot of cracks and voids.