硫化物夹杂对钢点蚀行为的影响

Effect of sulfide inclusions on pitting behavior of steel

通过控制冷却速率在钢中得到3种不同尺寸和分布的硫化物夹杂,采用在3%Na Cl溶液中的极化实验比较点蚀诱发敏感性,并观察腐蚀后的形貌。结果表明:随着冷却速率增加,硫化物夹杂尺寸降低,聚集型硫化物增多;随硫化物夹杂平均尺寸减小,点蚀电位和极化电阻均先升高后降低;随着聚集型硫化物的增多,硫化物夹杂在分布上的关联性加大,夹杂物引起的蚀孔关联起来形成更大的蚀孔,使钢的点蚀敏感性升高。

Three kinds of different size and distribution of sulfide inclusions were obtained by controlling the cooling rate of steel. The pitting sensitivity of steel was studied by using polarization experiments in 3% NaCl solution, and the corrosion morphology observed by means of SEM after pitting. The results show that with the cooling rate increases, the size of sulfide inclusions reduces and the number of the aggregate inclusion increases. With the average size of sulfide inclusions reducing, the pitting potential and polarization resistance of the sample increase first and then decrease. With the number of the aggregate inclusions increasing, the correlation with the distribution of sulfide inclusions increases, the large pits formed by the small pits aggregate make the pitting sensitivity of the steel increase.