钢板桩钢耐海水腐蚀及暴晒性能研究完稿.doc

本科毕业论文 题目： 钢板桩钢耐海水腐蚀及暴晒性能研究 学 院: 材料与冶金学院 专 业: 金属材料工程 学 号: 3 学生姓名: 黄 进 指导教师: 袁泽喜 日 期: 2010年6月3日  摘 要 钢板桩钢具有良好的耐海水腐蚀性能，这是由于在钢的表面生成了致密的保护性内锈层耐蚀钢在海水环境下的耐蚀性能下降，是因为海水中的Cl-使钢的表面不能形成致密的内锈层，锈层起不到保护作用的结果。本文通过干湿交替周浸试验来模拟海水环境下钢板桩钢的腐蚀行为，通过扫描电镜、能谱仪和动电位极化曲线等分析测试方法，观察锈层表面形貌和截面形貌，分析合金元素截面分布和锈层的相组成，并测试表面无锈层的低合金钢的电化学性能，计算腐蚀速率，从而主要获得以下的主要结论： 在基体成分钢的基础上添加高含量的P(0.082%)使得钢的耐海水腐蚀性能有所升高，加入含量比较高的Cu(0.40%)、Ni(0.11%)和Cr(0.21%)也提高了钢的耐蚀性。其组织为多边形铁素体和块状珠光体及粒状贝氏体。周浸试验240h后的高P钢的腐蚀速率最小。在腐蚀时间较短时，锈层表面主要由黄褐色及橘黄色锈层组成；随时间延长，试样表面主要由黑褐色的锈层组成，并出现明显的腐蚀坑。随腐蚀时间的延长，实验钢的腐蚀速率均是先快速增大到一定时间后，腐蚀速率减小。合金元素的含量对锈层成分影响不大，其主要腐蚀产物为Fe34、γ-FeH和α-FeOOH组成。 在本论文所选用的试验参数条件下，干/湿交替周浸试验能够较好的反映P、Cu元素存在的海水环境条件下钢铁的腐蚀趋势。周浸实验可以作为评价材料耐蚀性的有效手段。 Abstract?? The Sheet piling steels show considerable resistance to seawater corrosion through the formation of a dense and compact inner rust layer, but it is difficult to form in seawater environments containing Cl-. The corrosion behavior of sheet piling steels was studied by the wet/dry cyclic contusion tests which are commonly used to simulate the corrosion of the low alloy steels in the seawater environments. The relation among the structure of rust and corrosion resistance，corrosion rate and the influence of the added alloy elements of P, Cu and Cr were analyzed by potentiodynamic (PD) tests, scanning electron microscopy (SEM), energy dispersive spectrum (EDS). Mainly judgments have received the following main conclusions: In the matrix composition steel adding high P (0.082%) makes corrosion resistance of the steel increased in seawater, adding the higher content of Cu (0.40%), Ni (0.11%) and Cr (0.21%) also improves corrosion resistance of the steel. The organizations are the polygon ferrites, block pearlites and grainy bainites. After the 240h cyclic contusion of the contenting high P steel has the smallest corrosion rate. The beginning of corrosion, the rust layer surface is mainly brown and orange; with developing of the time, the surface of specimens are mainly