船舶结构钢海洋环境点蚀模型研究之二:实船蚀坑形态与径深比时变模型

Pitting corrosion model of mild and low-alloy steel in marine environment-Part 2: The shape of corrosion pits

文章基于点蚀生长原理与实船蚀坑形态检测数据,对船舶受点蚀构件的两类主要蚀坑的形态、形成机制及其随船龄演化情况作了大致描述。认为遭受点蚀船舶构件的蚀坑形态与其所处位置、服役时间等密切相关;两类蚀坑形态差异的原因在于其各自点蚀进程中的具体控制因素及相应的影响程度存在较大区别。论述证明将点蚀蚀坑径深比处理成随时间变化的函数是有理论和事实依据的;并与点蚀深度模型相结合,依据Yamamoto实测散货船货舱区肋骨蚀坑数据建立了相应的蚀坑径深比时变模型。

According to the pitting corrosion mechanism and corrosion data trom ship structure investigated, the shape of corrosion pits and its formation on ship structures were surveyed and summarized in this paper. It was shown that the main pits shape may be cone or compound-cone. Obviously, the shape of cor- rosion pits on ship structures was affected by its locations and ship age.The shape difference between those two pits type was resulted from the divergence in their corrosion-control factors and their influencing degree.It will be reasonable to describe the ratio of diameter to depth of corrosion pits as a function of ship age. The time dependent model of pits ratio was also established in this paper, based on the model of corrosion pits depth and the corrosion data of hold frames in cargo holds from literatures.