Corrosion of Bare and Galvanized Mild Steel in Arabian Gulf Environment (original) (raw)
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Atmospheric corrosion of mild steel in Oman
Hyperfine Interactions, 2006
A systematic study has been made of the initial corrosion products which form on mild steel capons exposed near the coastal region of Oman and at some industrial areas. The phases and compositions of the products formed at different periods of exposure were examined by using Mössbauer spectroscopy (295 and 78 K) and X-ray diffraction (XRD) techniques. The results show that lepidocorcite and maghemite are early corrosion products and goethite starts to form after two months of metal exposure to the atmosphere. Akaganeite is an early corrosion product but it forms in marine environments only, which reflects the role of chlorine effect in the atmosphere. The twelve months coupons showed the presence of goethite, lepidocorcite and maghemite, but no akaganeite being seen in the products of one of the studied areas.
UCTEA Chamber Of Metallurgical and Materials Engineers, 2021
Corrosion-induced degradation of marine steel structures is highly dependent on the surrounding environmental conditions and so varies significantly around global seawaters. This research has investigated the dependence of corrosion of carbon steel alloy for marine service on seawater composition and climatic conditions typical of the Arabian Sea. Natural and polluted seawater sites in the Arabian Sea were selected for field exposures. In addition, environmental conditions spanning those anticipated for the shipping structures operating in the Arabian Sea have been simulated in laboratorybased experiments by using heated and aerated artificial seawater. Following their exposures, the performance of samples have been investigated using the weight-loss and dimensional metrology methods. High overall corrosion losses were observed in the polluted seawaters than in the natural seawater conditions of Arabian Sea.
Steel Corrosion by Air: South of the Sahara
Steel is enriched iron (74.5-98.4% Fe) with major metal components and trace elements but its impurities affect the strength. Exposure to an electrolytic air/solution in the atmosphere oxidises the iron component into iron oxides to cause corrosion which speeds up after a long period of exposure at critical pH range of 7.85.5. This deterioration may occur uniformly or unevenly when a potential difference is created which may show defects of various textures as pits. Based on the concentration of chlorite, corrosion either commences at the outer or inner rim. Aggressive local corrosion may occur within cracks and crevices. Weathering of rocks could also release into the air and rain, soluble salts which may include sodium chloride. Fine dust which is more severe during the Harmattan over the region south of the Sahara Desert, usually contains sulphide and various salts that could reduce humidity levels. Hence in the Sahel regions, the first rainwater contains also inorganic anions such as NO3-and SO4 2-while suspended dust in the air from soil may have elevated levels of Cl − which promotes corrosion. The rate of electrochemical reactions, diffusion processes and increase in temperature also speed up rate of corrosion.
Atmospheric corrosion of different steels in marine, rural and industrial environments
Corrosion Science, 1999
The atmospheric corrosion of the dierent steels at the dierent exposure conditions has been investigated by MoÈ ssbauer and Raman spectroscopies and XRD. Goethite and lepidocrocite were identi®ed in the corrosion products formed on all the coupons. Magnetic maghemite, which resulted in the high corrosion rate, formed on the carbon steel exposed at the marine site. The inner layer, a protective layer, mainly consisted of interdispersed goethite, and the outer layer mainly composed of interdispersed lepidocrocite. The larger fraction of superparamagnetic goethite, which resulted in decreasing the mean particle size of goethite, in the corrosion products was closely related to reduction in the corrosion rate in the marine and rural sites. The larger amounts of silicon and smaller amounts of phosphorus in the steel increased the fraction of superparamagnetic goethite. However, dierent amounts of nickel did not aect the formation of the iron oxides after sixteen years of exposure.
Evaluation of Steel Corrosion Products in Tropical Climates
CORROSION, 1997
Phase variations occurring in corrosion products obtained in steels exposed to different zones of tropical climate in Cuba and Venezuela were determined to establish their relationship to corrosion phenomena. Steel corrosion products were obtained at four test stations in both countries with marine, industrial, and rural characteristics. Phase composition was determined using x-ray diffraction (XRD), infrared (IR) spectroscopy, and Mössbauer spectroscopy. In the rural climate of both countries, the predominant phase was lepidocrocite (␥-FeOOH), which was in agreement with reported corrosion rates. In the marine environments, corrosion products varied in composition. In Adicora, Venezuela, akaganeite (-FeOOH) was found, but in Cuba, this phase was nonexistent. Results were discussed in light of the contamination present and meteorological parameters recorded in the test zones.
Corrosion behaviour of cast iron exposed to Arabian Gulf environment
Anti-Corrosion Methods and Materials, 2011
... Omar A. Eid, Royal Commission for Jubail and Yanbu, Jubail Industrial City, Saudi Arabia. ... The pH is usually neutral or slightly acidic. The corrosion rate in industrial and marine areas may be several times that in a rural region (Barton, 1976). ...
Corrosion behaviour of metals and alloys in the waters of the Arabian Sea
Corrosion prevention and Control, 1990
F UR TYPES of metals (mild steel. brass. alum!nium and stainless st~el) were exposed during the I~eriod Novemb~r, 1987, to November, 1988, at depths exceedmg IOOOm In the Arabian Sea, m order to assess thezr behavIOur with respect to corrosion. The results indicated an increase of the corrosion rate of mild steel and brass with increased depth, whereas in the case of stainless steel and aluminium. the corrosion rate decreased with increased depth. This difference in behaviour with respect to depth could be attributed to the characteristic way that metals and alloys react with the dissolved oxygen present in the water column.
Atmospheric corrosion of mild steel
2011
The atmospheric corrosion of mild steel is an extensive topic that has been studied by many authors in different regions throughout the world. This compilation paper incorporates relevant publications on the subject, in particular about the nature of atmospheric corrosion products, mechanisms of atmospheric corrosion and kinetics of the atmospheric corrosion process, paying special attention to two matters upon which relatively less information has been published: a) the morphology of steel corrosion products and corrosion product layers; and b) long-term atmospheric corrosion (>10 years).
Materials and Corrosion, 2020
In this study, the behavior of carbon steel and galvanized steel in nontropical coastal marine environments was evaluated. Evaluation was carried out with specimens with dimensions of 10 cm × 10 cm × 0.3 cm. These specimens were exposed to four testing stations (Iquique, Mejillones, Los Vilos, and San Vicente), where racks were installed both at ground level (ground), as well as in the upper zone of electrical transmission towers (tower). In each station, 24 specimens of A36 carbon steel and galvanized steel were placed (12 each). The corrosivity of the environment was measured using the ISO 9223, 9225, and 9226 standards. The specimens were evaluated on-site, monthly, through visual inspection and photographic record. Once withdrawn, the corrosion rate was determined and the corrosion products were analyzed through Raman and Fourier-transform infrared. The results show that, in all cases, the corrosion rate is greater in the tower than on the ground. However, even though the Los Vilos station is located farther from the sea (3,500 vs. ≈500 m), the corrosion rate of steel in the tower is the highest. This is caused by the generation of HCl from the transformation of lepidocrocite into goethite, in the presence of low chloride content, which acidifies the steel/corrosion product interface. In the case of galvanized steel, the corrosion rate is a function of the chloride content in the atmosphere, obtaining an excellent correlation between both parameters.