不锈钢复合钢材及其焊接接头耐腐蚀性能试验研究

Experimental Study of Corrosion Resistance of Stainless-Clad Bimetallic Steel and Welded Connections

为研究不锈钢复合钢材及其焊接接头在海洋大气环境中的耐腐蚀性能,分析复合钢板复层、基层、焊缝以及复合界面的腐蚀速率、腐蚀形貌和腐蚀产物,对4组共97个试件进行了盐溶液周浸试验,模拟大气腐蚀环境中浸润、潮湿、干燥的表面状态,并通过高温、高湿、高氯离子浓度特征模拟热带海洋环境中加速腐蚀的效果.试验采用腐蚀失重法评测试件的腐蚀速率,并采用扫描电子显微镜、能谱仪和表面形貌仪等设备对试件表面的宏观和微观腐蚀形貌以及锈层成分进行观测分析.试验结果表明,在海洋大气腐蚀环境中,不锈钢复合钢板的复层及焊缝处基本保持原状,而基层碳钢的腐蚀现象较明显,并且因为电偶腐蚀的存在导致碳钢的腐蚀加速.此外,表面粗糙度也在一定程度上影响了基层碳钢的腐蚀速率.本研究为不锈钢复合钢材在海洋大气环境下的暴露试验提供了数据支撑,并为其海洋工程应用提供了耐腐蚀性能方面的参考.

To study the corrosion resistance of stainless-clad(SC)bimetallic steel and welded connections in the marine atmospheric environment,and to clarify their corrosion characteristics,including the corrosion morphology,corrosion rates,and corrosion products,we conducted alternate immersion tests in salt solution.We tested 97 specimens in four groups in a simulated marine atmospheric corrosive environment.To accelerate the corrosion rate and simulate the tropical marine environment,we generated test conditions with high temperature,high humidity,and a high chloride concentration.To determine the corrosion rate of the specimens,we used the corrosion weight loss method.The macroscopic corrosion morphology and appearance and the rust layer composition on the surface of the specimens were obtained and analyzed using a scanning electron microscope(SEM),an energy spectrometer,and a surface profiler.The test results indicate that the stainless steel in the cladding layer and weld seam of the SC bimetallic steel remained basically uncorroded,whereas the carbon steel in the substrate was visibly corroded.The corrosion rate of the carbon steel was accelerated by the presence of galvanic corrosion.Surface roughness also affected the corrosion rate to some extent.These research outcomes provide data support for tests of the exposure of SC bimetallic steel to the marine atmospheric environment as well as guidance for the design of corrosion-resistant SC bimetallic steel in marine engineering.