Papers by Keyword: Crevice

Abstract: Water gate is one of important equipments for arbitrating water supply and maintaining safety of dam. Water gate is made of high tensile strength of steel plate, this kind of steel plate used as constructional material of water gate is weighed for the economical consideration. Steel plate must be cut, welded and rivet to manufacture water gate. Thus, there are some crevices, induced by the defects of material, bad construction, seismic excitation and errors of size, on water gate. This phenomena causes stress concentration, induced high crack increase rate, affect the safety and usage of water gate. In this research, digital image correlation method is developed to measure the mechanics behavior of single steel plate and bi-steel plate with crevices under tension force according to the characteristics of water gate filed test. The test and analysis results of laboratory test reveal that this digital image correlation method can easily indentify the corrosion point on the steel plate. Otherwise, the crack variation of crack tip of steel plate-single steel plate and bi-material steel plate under loadings can be easily identified by the laboratory test.

Abstract: This paper summarizes the results of various attempts to implement a neural network for solving corrosion problems. The first activity was aimed to develop a model able to predict crevice corrosion of stainless steel and related alloys in chloride containing media from long-term exposure tests. Second, the preliminary evaluation of a neural network approach for rapid prediction of naphthenic acid corrosion performance (NAC) of carbon and stainless steels in a crude oil distillation unit will be described. In this work, the neural network was trained on the basis of experimental data from laboratory experience. Finally, non-deterministic models based on artificial neural network (ANN) were developed to predict the corrosion rate of carbon steel in CO2 environment by elaborating laboratory and field data. NN models were developed and tested using, as an input, pattern physico-chemical variables typically met in empiric and mechanistic models as well as parameters apparently not involved in the corrosion phenomenon. Results confirmed the validity of the NN approach

Abstract: Aqueous corrosion behaviors of Fe3Al-based iron aluminides were investigated. From the result of cyclic anodic polarization tests conducted in 3.5 wt.% NaCl solution at 25, 48, 72 and 95°C, as the temperature increased, the resistance to pitting corrosion decreased significantly, especially over the range of 25~48°C. From the result of crevice corrosion tests, no crevice corrosion occurred on FAL-Mo in the lower chloride-containing solution (200 ppm Cl-), however, FAL-Mo did not perform as well as the 304L SS in the higher chloride-containing solution (3.5 wt.% NaCl). From the result of anodic polarization tests performed in sulfur-compound solutions, additions of Cr and Mo to the Fe3Al-based iron aluminides tend to improve the aqueous corrosion resistance. Aqueous corrosion behaviors with different Al content evaluated by cyclic anodic polarization test in the chloride-containing solution exhibited the more stable passive behavior and the higher pitting resistance as Al contents increased.