常用铸铁材料海水腐蚀行为的研究

STUDY OF CORROSION BEHAVIOR ON COMMON CAST IRON MATERIALS EXPOSED TO SEAWATER

对常用铸铁材料在实海和流动海水条件下的腐蚀性能进行了测试 ,分析了铸铁中不同石墨形态、基体组织、低合金化对铸铁腐蚀性能的影响机理 .结果表明 :片状石墨铸铁耐腐蚀性能优于球状石墨的铸铁 ;球状石墨铸铁平均腐蚀率最小 ,但具有强烈的点蚀倾向 ;铸铁在实海中的腐蚀行为以化学 -电化学溶解为主 ,流动海水中的冲蚀 -磨蚀进一步加剧其化学 -电化学溶解 .

The corrosion properties of common cast iron materials in static (flowing velocity is about 0.1 m/s)and flowing seawater were tested,and effects of graphite morphology,matrix microstructure and low alloying treatment on corrosion properties of cast irons were analyzed.The experimental results indicate that the corrosion-resistance property of flake graphite samples is superior to that of spherical graphite samples.The average corrosion rate of spherical graphite samples,compared with other samples,was little,but its tendency of pitting corrosion is intensively obvious.For samples in static and low flowing seawater (flowing velocity is more than 3 m/s),chemistry-electrochemistry dissolution mechanism is almost wholly responsible for their corrosion behavior.As to samples in high flowing seawater (flowing velocity is equal to or more than 7 m/s),erosion-ablation behavior further accelerates chemical-electrochemical dissolution.