Incoloy 825/L360复合管焊接接头耐蚀性研究

目的研究Incoloy 825/L360复合管焊后的焊缝耐蚀性能。方法以Incoloy 825/L360复合管为研究对象,选用Inconel625焊材进行了镍基合金焊缝的焊接,并对焊缝和Incoloy 825母材在质量分数为3.5%的NaCl溶液、6%的FeCl_3溶液中进行电化学试验,并对其耐蚀性进行了对比分析。结果在质量分数为3.5%的NaCl溶液中,不同温度下母材自腐蚀电位均高于焊缝,自腐蚀电流密度均小于焊缝,随着温度的升高,母材的自腐蚀电位和焊缝的自腐蚀电流密度均增加,母材的自腐蚀电流密度变化不明显;在质量分数为6%的FeCl_3溶液中,母材与焊缝的自腐蚀电位整体较高,母材的自腐蚀电流密度高于焊缝,不同温度下焊缝极化曲线均存在明显的钝化平台。结论 Incoloy 825母材和焊缝在两种溶液中的耐蚀性存在一定差异;在质量分数为3.5%的NaCl溶液中,母材腐蚀对温度不敏感,焊缝的腐蚀敏感倾向性随着温度的升高而增大,腐蚀敏感性高于母材;在质量分数为6%的FeCl_3溶液中,不同温度下的焊缝极化曲线均存在明显的钝化平台,腐蚀敏感性低于母材。

Corrosion Resistance of Incoloy 825/L360 Composite Pipe Welded Joints

The work aims to investigate the weld corrosion resistance of Incoloy 825/L360 composite pipe after welding. With Incoloy 825/L360 composite pipe as the research object, Inconel 625 welding material was used to weld nickel-based alloys. The weld and Incoloy 825 base metal were subjected to electrochemical tests in 3.5% NaCl solution and 6% FeCl3 solution and the corresponding corrosion resistance was compared and analyzed. In 3.5% NaCl solution, the self-corrosion potential of the base metal was higher than that of the weld at different temperature, and the self-corrosion current density was less than that of the weld. As the temperature increased, the self-corrosion potential of the base metal and the self-corrosion current density of the weld increased. The self-corrosion current density of the base material did not change significantly. In the 6% FeCl3 solution, the self-corrosion potential of the base metal and the weld was generally higher, and the self-corrosion current density of the base metal was higher than that of the weld. There were obvious passivation platforms at the polarization curves of the weld at different temperature. Incoloy 825 base metal and weld have different corrosion resistance in these two solutions. In 3.5% NaCl solution, the corrosion of base metal is not sensitive to temperature. The tendency of corrosion sensitivity of welds increases with increasing temperature, and the corrosion sensitivity is higher than that of base metal. In the 6% FeCl3 solution, there are obvious passivation platforms in the weld polarization curves at different temperature, and the corrosion sensitivity is lower than that of the base metal.