某船水线下外板腐蚀原因分析及启示

Analysis and inspiration on causes of underwater outer plate corrosion of a certain ship

本文概述了船舶外板发生腐蚀现象的可能原因,针对某船主船体水线下部位有明显缺欠凹坑的腐蚀现象开展了原因分析。经过原因及机理分析可知该船水线下外板快速腐蚀是异常的,且该船发生了杂散电流腐蚀。导致外板异常腐蚀的原因是船舶下水后使用码头电焊机进行施工作业时排流接地不良引起的杂散电流腐蚀。利用故障树分析法对可能引起杂散电流腐蚀的因素进行了分析,建议下水后的船舶通过排流导线与码头接地回路保持良好连接,严格落实用电施工接地要求可避免此类问题的重复发生。

This paper provides an overview of the possible causes of the outer plate corrosion of ships,and conducts a root cause analysis on the corrosion phenomenon of obvious defects and pits in the underwater part of a certain ship.After analyzing the causes and mechanisms,it is known that the rapid corrosion of the underwater outer plate of the ship is abnormal,and the ship has encountered stray current corrosion.The main reason for the abnormal corrosion of the outer plate is the stray current corrosion caused by poor grounding during the construction operation of the dock welding machine after the ship is launched.The failure tree analysis method is used to analyze the factors that may cause stray current corrosion.It is recommended that the ship after being launched maintain a good connection with the dock grounding circuit through drainage wires.Strict requirements on implementation of electrical construction grounding can avoid the recurrence of such cases.