Abstract: Cyclic voltammetry was used to comprehensively investigate the fundamentals of the electrochemical corrosion reactions occurring at the steel／solution interface in Yingtan soil simulated solution． The interrelation between anode polarization and the cathodic hydrogen evolution was studied by changing the sweep rate， the upper potential limit，ions concentration and gas conditions．The results show that the electronically behaviors of X80 steel are irreversible charge transfer process．There is no stable oxide film formed on the steel surface． The anode polarization and cathodic hydrogen evolution reaction are enhanced by the corrosive ions in the solution ．The hydrogen evolution was catalyzed by the stable deposition film which generated during the anode polarizing．The introduction of oxygen could form a stable oxide film，which weakened the
catalysis to the hydrogen evolution．The stress corrosion cracking sensitivity of the welded metal is increased by CO_２ introduced to the solution．

Key words: X８０ steel , Welded metal , Cyclic voltammetry , Corrosion

摘要： 用循环伏安法研究了X８０ 钢及其焊缝在鹰潭土壤模拟溶液中，溶液／电极界面上的电化学腐蚀反应。通过改变扫描速率、阳极电位上限、离子浓度、通气状态研究了钢的阳极极化和阴极析氢反应之间的相互作用。结果表明，酸性环境中的X８０ 钢电化学行为是不可逆的电荷转移过程，钢的表面不能形成一个稳定的氧化膜。溶液中的侵蚀性离子使阳极极化和阴极析氢反应程度增加。阳极极化产生的稳定沉淀层对析氢反应起催化作用。氧气的存在能使钢表面能生成稳定的氧化膜，这会降低对析氢反应的催化作用。溶液中的CO２ 能增加焊缝的SCC 敏感性。

关键词: X80 钢 , 焊缝 , 循环伏安 , 腐蚀