稀土氧化物对焊条熔敷金属抗高温硫化腐蚀机制的研究

Effect of Rare Earth Oxides on High Temperature Sulphidation Resistance of Weld Metal

通过在焊条药皮中分别添加稀土氧化物La2O3及CeO2,研究其对焊条熔敷金属在含硫气氛中腐蚀性能的影响。并在此基础上,进一步分析了稀土氧化物对焊缝金属抗高温硫化腐蚀的作用机制,结果表明:稀土氧化物在焊条药皮中的加入使熔敷金属抗高温硫化腐蚀性能有显著提高,添加La2O3的焊条熔敷金属比添加CeO2的焊条熔敷金属具有更好的抗高温硫化腐蚀性能。提高焊缝金属抗高温硫化腐蚀性能的机制,与稀土元素在焊缝组织中的分布、减少内硫化的加速腐蚀过程相关。

Through the addition of rare earth oxides La2O3 and CeO2 in the electrode covering, their effects on high temperature sulphidation resistance of the weld metal were tested. The mechanism of rare earth oxides＇ effect on high temperature sulphidation resistance of weld metal was studied. The result showed that addition of rare earth oxides in the electrode covering could improve the high temperature corrosion resis- tance in sulphureous environment. The weld metal with La2O3 addition had better high temperature sul-phidation resistance than that of the weld metal with CeO2 addition. The inner sulphidation mode was considered to be the main reason of fast corrosion in high temperature sulphur enriched gas. The effect of rare earth oxides on high temperature sulphidation resis-tance of weld metal was related to the distribution of rare earth oxides in the weld metal. The rare earth could react with sulphur and slow down the inner sulphidation process, thus improving the high tempera- ture resistance of weld metal.