采用恒电位电化学极化试验, 测试了三种不同化学成分的高频焊管(HFW)焊缝腐蚀行为。结果表明, 在3.5% NaCI溶液中进行电化学极化试验144 h后, 三种不同成分的HFW焊管焊缝区表现出不同的腐蚀速率。C、Mn含量低的试样(0.043% C, 0.25% Mn), 焊缝表现出较好的抗沟槽腐蚀性能, 沟槽腐蚀敏感系数平均值为1.06, 即不敏感; 当C、Mn含量增大后(0.11% C, 1.0% Mn), 沟槽腐蚀敏感系数平均达到1.75, 焊缝表现出明显的选择性优先腐蚀。微观分析表明, C、Mn含量提高后, 母材中的组织偏析使焊缝组织和成分均匀性变差, 是造成焊缝优先腐蚀的主要原因。Cu合金元素的添加有助于提高HFW焊缝抗沟槽能力。

Electrochemistry polarization method is applied to investigate the grooving corrosion sensitivity of weld seams of HFW pipe. The grooving corrosion sensitivity coefficient of three types of the HFW pipe has been tested after polarized for 144 h in 3.5% NaCl solution.The results showed that the different chemical composition of HFW pipe has different corrosion rates. The HFW pipe of lowest content of C, Mn (0.043% C, 0.25% Mn) can decrease the grooving corrosion sensitivity coefficient to some extent, and the average of value is only 1.06. However, With the increase of content of C,Mn (0.11% C, 1.0% Mn), the average of grooving corrosion sensitivity coefficient increase to 1.75, the weld seams exhibited obvious selective corrosion. Micro analyzing showed that, With the increase of content of C, Mn, material segregation also raised the uniformity of organization and composition, which caused mainly the corrosion preferred. The addition of Cu elements can improve the ability of anti grooving corrosion reaction.