采用不同轧制及热处理工艺制备了化学成分相同而晶粒尺寸不同的3种桥梁耐候钢。采用自腐蚀电位测试、模拟干湿交替加速腐蚀试验、锈层横截面微观形貌分析和XRD锈层物相分析等手段对桥梁耐候钢的晶粒尺寸和耐大气腐蚀性能之间的关系进行了研究。结果表明,晶粒最细的试样自腐蚀电位较高,在模拟干湿交替加速腐蚀试验后试样腐蚀速率最低,锈层也更致密。不同晶粒尺寸耐候桥梁钢形成的内锈层组成是相同的,说明锈层的结构和致密程度对腐蚀过程的具有重要的影响。

Three kinds of bridge weathering steels with different grain sizes and the same chemical composition wereprepared by different rolling and heat treatment processes.The relationship between grain size and atmosphericcorrosion resistance of these steels was investigated by corrosion potential test,simulated wet-dry alternatedaccelerated corrosion test,micro-analysis of rust cross section and XRD analysis of the corrosion products.Theresults show that the corrosion potential of the sample with the thinnest grain size was the highest.The corrosion rateand thickness reduction were the lowest and the rust layer was more compact for the bridge steel with the thinnestgrain size after simulated wet-dry alternated accelerated corrosion test.The composition of the inner rust layer formedon weathering steels with different grain sizes was the same,indicating that the structure and compactness of theinner rust layer have very important influence on the corrosion process.