铁素体不锈钢在排气系统冷凝液中的腐蚀特性研究

Research on Corrosion Characteristics of Ferritic Stainless Steel in Condensate of Exhaust System

通过分析国五排放法规下某自主品牌和某合资品牌汽车排气系统冷凝液的成分,设计了用于加速腐蚀实验的冷凝液配方,该配方中各组分的浓度均低于日本的JFE冷凝液。利用循环腐蚀方法,模拟排气系统腐蚀环境,研究了排气系统常用铁素体不锈钢SUH409L和439在这两种冷凝液中的腐蚀特性。结果表明:两种不锈钢材料在国五冷凝液中的腐蚀速度均小于在JFE冷凝液中的,30个实验周期后,SUH409L和439不锈钢在国五冷凝液中的质量损失是JFE冷凝液中的27%和45%;439不锈钢在两种冷凝液中的耐腐蚀性均优于SUH409L不锈钢的,439不锈钢在JFE冷凝液和国五冷凝液中的质量损失是SUH409L不锈钢的42.8%和72.4%。

Based on the analysis of the components of condensate in exhaust system of a self-owned brand and a joint venture brand vehicle under the national fifth emission standard (CN 5),a condensate formulation for accelerated corrosion test was designed.The concentration of each component in the formulation was lower than that in JFE condensate of Japan. The corrosion characteristics of ferritic stainless steels SUH409L and 439 in the two kinds of condensates were studied by simulating the corrosion environment of exhaust system with cyclic corrosion method.The results show that the corrosion rate of the two stainless steel materials in the condensate of CN 5 is lower than that in the JFE condensate.After 30 test cycles,the mass loss of SUH409L and 439 stainless steel in CN 5 condensate is 27% and 45% of that in the JFE condensate,and the corrosion resistance of 439 stainless steel in both condensates is better than that of SUH409L.The mass loss of 439 stainless steel in JFE condensate and CN 5 condensate is 42.8% and 72.4% of SUH409L stainless steel.