显微组织对建筑用耐腐蚀钢筋耐腐蚀性的影响

Effects of Microstructure on Corrosion Resistance of Corrosion Resistant Reinforcement Bar in Building

以3.5%Na Cl溶液为腐蚀环境,对不同显微组织的耐腐蚀钢筋进行不同周期的干/湿循环加速腐蚀实验。研究了不同显微组织对耐腐蚀钢筋腐蚀性的影响。结果表明,显微组织为铁素体＋珠光体的试样腐蚀288 h后腐蚀率趋于稳定,显微组织为铁素体＋贝氏体的钢筋试样腐蚀144 h后腐蚀率趋于稳定。上述两种钢筋在周期为72 h时腐蚀率差距最大,288 h时腐蚀率相接近,为4.1 g/（m^2·h）左右。两种实验钢筋锈层的主要物相均为Fe3O4、γ-Fe OOH、α-Fe OOH及少量Na Cl,随着实验周期的延长,Na Cl逐渐消失。锈层成分主要由腐蚀环境决定。

Taking 3.5% Na Cl solution as corrosion environment, the accelerated corrosion tests of dry/wet cycling of the corrosion resistant reinforcement bar with different microstructure were carried out in different cycles. The effects of different microstructures on the corrosion resistance of the corrosion resistant reinforcement bar were studied. The results show that the corrosion rate of the samples with the microstructure of ferrite ＋ pearlite after corrosion for 288 h is stable and the corrosion rate of the samples with the microstructure of ferrite ＋ bainite after corrosion for 144 h is stable. The gap of corrosion rate of the two kinds of the above samples is the maximum at 72 h, and the corrosion rate is close at 288 h, which is about 4.1 g/（m^2·h）. The main phase of the two test reinforcement bars are Fe3 O4, γ-Fe OOH, α-Fe OOH and a small amount of Na Cl. With the test cycles increases, Na Cl gradually disappears. The composition of the rust layer is mainly determined by the corrosion environment.