Corrosion Behavior Of Q235 Steel With Alternated Dry And Wet Period In Simulated Environment

Inductive Resistance Probe (IRP) is used due to features including rapid response, strong adaptive ability and real-time measurement. But the limitations of the probe materials blocks the further applications of the probe and few reports in this field can be seen. In this paper, an atmospheric corrosion measurement system based on IRP was established. The data collected by IRP measurement system was processed by Integration Filter Algorithm (IFA).Electrochemical Noise (EN) is an in-situ and nondestructive technology, and also can be used in the measure of metal atmospheric corrosion due to its simple test equipments and good suitability to testing system. In this paper, carbon steel atmospheric corrosion measure method based on elements of ACM was presented. The result of experiments showed that the measurement system established was suited for detection of carbon steel atmospheric corrosion; the data collected can characterize metal corrosion process under thin liquid film which is basic condition of atmospheric corrosion.The total atmospheric corrosion of carbon steel was determined by corrosion time and the rate in the period.The corrosion time could be exactly measured by EN measurement system. Consistence of the observation and measurement showed that it was available to represent the drying time with observed result.In the simulated air, the relationship was obtained by fitting the data of drying time (Td) of surface, temperature (Temp.), relative humidity (RH) and wetting time (Tw). The linear equation of Td of surface dependent on Temperature and RH was calculated at environmental temperature, in which the influence of Tw on Td was represented as a constant.The corrosion of carbon steel in different simulated air was studied based on two measurement systems for atmosphere corrosion. The result showed that the effect of the main contamination in atmosphere in Temperature=18℃, RH=70, in which [CO32-]=0.01mol/L, [SO42-]=0.01mol/L, [Cl-]=0.001mol/L were included, was described as CO32->SO42->Cl-; The total corrosion was dependent on the increasing corrosion rate and shorted corrosion time with the rising of temperature. There was extremum of corrosion rate with the increasing of relative humidity after the thin liquid film was formed on the surface of carbon steel.