Results of studying atmospheric corrosion in Vietnam 1995–2005

Abstract

Vietnam is situated in the wet tropical zone; thus, atmospheric conditions are characterized by high temperatures and a long time of wetness (TOW). In addition, the salt air coming in from the sea causes a high chloride concentration in coastal areas. Furthermore, Vietnam is a developing country, which means that air pollution is increasing with the development of industry. These factors result in significant damage to materials by atmospheric corrosion. In this report, the results of a recent study on the corrosion of carbon steel and zinc-galvanized steel at 6-8 testing sites in Vietnam over 10 recent years (1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005) are focused on as well as the effects of environmental factors on atmospheric corrosion. The results showed that the corrosion of carbon steel is dominated by TOW, whereas zinc-galvanized-steel corrosion strongly depends on the chloride ion concentration in the air. The corrosion losses of both carbon-and zinc-galvanized steel fit the power model well with high correlation coefficients. In addition, the characteristics of the Vietnamese climate are introduced in the form of distribution maps of temperature (T), relative humidity (RH), total rainfall and TOW. A relationship between TOW, T and RH was found that enabled the calculation of TOW from T and RH data, which are available at meteorological stations. Finally, atmospheric corrosivity is determined on the basis of data on TOW, Cl À and SO 2 concentrations, and the carbon steel corrosion rate. It is shown that in Vietnam, TOW is so long that the corrosion rate of carbon steel is in the C 3 category; nevertheless, Cl À and SO 2 concentrations in the atmosphere are not high. r

Corrosion of stainless steel water storage tanks exposed in coastal atmospheric conditions

“…The values of climatic parameters were obtained from local weather stations. Time-of-wetness (TOW) was calculated based on annual temperature and RH data, using an empirical equation described in [9]. Airborne salinity and sulfur dioxide concentrations were taken from Lien L.T.H.…”

“…Airborne salinity and sulfur dioxide concentrations were taken from Lien L.T.H. work [9]. The reported salinity values were converted from results determined by "dry gauze" method into respective "wet candle" method with twofold multiplier.…”

Corrosion rate prediction and influencing factors evaluation of low-alloy steels in marine atmosphere using machine learning approach

“…For instance, Panchenko et al [ 11 ] proposed a forecast method of corrosion losses for a period of up to 50 years (with error within ± 30%) by regression analysis of 1-, 2-, 4- and 6-years’ corrosion data. In researches about the effects of exposure time, alloying elements, and environmental factors on corrosion resistance, the regression analysis is widely applied [ 12 – 14 ]. In conventional regression analysis, linear function, polynomial function and power function are mostly used [ 1 , 15 ].…”

An accelerated testing method for the evaluation of atmospheric corrosion resistance of weathering steels

“…Commonly, atmospheric corrosion kinetics can be expressed by the equation D ϭ A · t n , where D is the weight loss in terms of thickness; t is the exposure time; and A, B are constants (Legault and Preban, 1975;Wei, 1991;Lan et al, 2006;Lien et al, 2007). The validity of the equation and its reliability to predict long-term corrosion behavior has been demonstrated (Feliu and Morcillo, 1982;Legault and Preban, 1975;Morcillo et al, 2013;Zhang et al, 2002;Bohnenkamp et al, 1973;Pourbaix, 1982;Benarie and Lipfert, 1986).…”