Study on Mechanism of Corrosion and Fracture for the Structure Material of Ship and Copper Alloy Pump Sets

• Main Authors: Shih-Kuo Chou, 周世國
• Other Authors: 于劍平
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/46112805239880054554

碩士 === 崑山科技大學 === 機械工程研究所 === 98 === Nowadays, in the early stage of shipbuilding, several blocks of the ship were made and then combined into a ship. The typically technique of combined ship blocks was welding. And the ships usually sail in the complex environments of sea corrosion and strong wave stress. They will induce serious corrosion or fracture if improper materials are utilized on ship. Therefore, the failure of corrosion and stress was aimed in this study, and we make a systematic study for mechanism of practical failure. First part of this study is to analyze the external fracture of ship that made of low carbon steel previously the welding, complex strength and chloride corrosion. Second, the bronze pump impellers lost their function due to internal decomposition that caused by seawater corrosion and erosion for a long period of time. It will split the case with appropriate size was observed for macroscopic objects, microstructure and crack shape with SEM. And analyze the mechanism of corrosion products were examined by EDS. According to the result of experiment, it is analyzed that the fractures occurred on ship equipment of low carbon steel for the reasons heat affected zone after repair by welding, long-term surrounded in rich chloride seawater, and various wave strength when sailing. Moreover, the continuously flowing turbulent water and the chloride of seawater cause the impeller of pump corrosion. This study was to determine rational of damaged parts, and will be acceptable methods of ship designing and selecting the correct materials for future references.