304L/SA516Gr70不锈钢复合板焊接接头的耐蚀性研究

采用化学浸泡和电化学腐蚀测试技术,研究分别采用ER316L和ER309L焊丝作为过渡层填充材料焊接获得的304L/SA516Gr70不锈钢复合板接头的耐点蚀性能。结果表明,两种接头在质量分数5%FeCl3溶液和质量分数10%FeCl3溶液中的腐蚀速率都很小,未发生明显的点蚀现象。在质量分数15%FeCl3溶液中,ER316L接头的腐蚀速率要小于ER309L接头,且通过显微镜观察发现其腐蚀坑大小也明显小于ER309L接头。室温下,在质量分数3.5%NaCl溶液中几种接头和304L母材的自腐蚀电流大小顺序依次为:ER309L接头>ER316L接头>304L母材,两种接头的耐点蚀性能只略低于304L母材,能够满足工程结构对复合板接头的耐蚀性要求。

Study on Corrosion Resistance of Welded Joints of 304L/SAS16Gr70 Stainless Steel Composite Plates

The pitting corrosion performances of two different welded joints of 304L/SASI6Gr70 stainless steel composite plate which were welded with ER316L and ER309L filler metals respectively are studied with chemical immersion method and electrochemical tests respectively. Results show that the pitting corrosion rates of both ER316L joint and ER309L joint are very low in different corrosion solutions such as 5% FeC13 and 10% FeC13 , and no obvious pitting corrosion occurred. In 15% FeC13 corrosion solution, the pitting corrosion rate of ER316L joint is lower than that of ER309L joint, and the size of corrosion pitting of 316L joint is smaller than that of 309L joint. At room temperature and in 3.5% NaC1 solution, the corrosion current is in sequence of ER309L joint 〉 ER316L joint 〉 the base metal of 304L stainless steel, and the pitting corrosion resistances of ER316L joint and ER309L joint are a little lower than that of 30gL base metal. Both joints can meet corrosion resistance requirements when the 304L/SA516Gr70 stainless steel composite plate is applied in engineering structure.