Corrosion study of SS304 and SS316 alloys in atmospheric, underground and seawater splash zone in the Arabian Gulf Anwar Ul-Hamid a , Huseyin Saricimen b , Abdul Quddus a , Abdulrashid I. Mohammed a and Luai M. Al-Hems a a Centre for Engineering Research, King Fahd University of Petroleum & Minerals, Dhahran, Saudi Arabia; b Industrial Engineering Department, Yalova University, Yalova, Turkey ABSTRACT Bare stainless steel type 304 and 316 alloys were exposed to atmospheric, underground and seawater splash conditions in order to evaluate their corrosion properties. The exposure was undertaken for 15 months at the coastal and industrial city of Jubail located in the Arabian Gulf. The corrosivity of the environment was determined by testing the soil, groundwater, seawater and air quality. Corrosion rate of the exposed coupons was determined by weight loss method. The experimental results indicate that the both types of stainless steels corroded moderately in this environment. Primary factors influencing the corrosion process are thought to be high degree of variation in temperature and humidity combined with high chloride and sulphate concentrations. The corrosion rate of stainless steel is also compared with those reported for other international locations. ARTICLE HISTORY Received 23 May 2016 Revised 29 June 2016 Accepted 11 July 2016 KEYWORDS SS304; SS304; SS316; atmospheric; underground; corrosion; splash zone Introduction Atmospheres are often classified as rural, industrial or mar- ine. Some atmospheres are formed as a combination of these settings. For instance, there are seacoast locations mired by heavy industrial pollution and can be termed both marine and industrial. Moreover, two environments of a par- ticular type can differ widely in average yearly rainfall, humidity and temperature and therefore exhibit different cor- rosion tendency. Environment in the industrial city of Jubail located at the Arabian Gulf is extremely corrosive due to a combination of industry and coastal region [1–3]. This cor- rosive nature occurs as a result of variations in temperature and humidity and atmospheric contaminants present because of local petrochemical and oil industry, soil condition and bacterial activity. Atmospheric corrosion is accelerated by high temperature, high humidity, coastal setting, extended periods of wetting and presence of environmental pollutants such as sulphur oxides, nitrogen oxides, hydrogen sulphide, ammonia and carbonyl sulphide. The most important corrosive constituent of industrial atmospheres is sulphur dioxide, which originates predominately from the burning of coal, oil and gasoline. Corrosion in atmosphere accounts for more failures on a cost and tonnage basis than any other type of corrosion. Cor- rosion rate in an industrial and marine environment may be several times that in a rural region [4]. For example, corrosion of steel at the seacoast was found to be 400–500 times greater than in a desert area. Increase in humidity above a critical level (i.e. 50–70%) increases the atmospheric corrosion rate of common metals such as steel, nickel, copper and zinc [5–7]. Engineering components buried underground are exposed to soil corrosion. The salts, acids, alkalis and organic com- pounds present in the soil combine with soil moisture, con- ductivity, pH, oxygen concentration and bacteria to corrode materials [8–10]. In general, soils containing significant amounts of chloride and sulphate ions are known to be more corrosive. Another corrosive environment encountered by engineer- ing components is a setting above the seawater but not immersed in it, i.e. seawater splash zone. The surfaces of the components exposed to splash zone will exhibit wet and dry cycles. Conditions at the splash zone are generally more corrosive than at full immersion zone since in contrast to lat- ter, the material is exposed only to a thin layer of water which can readily transport dissolved oxygen (DO) [4]. The climate of Jubail where this study was conducted con- stitutes high temperature-high humidity regimes. The temp- erature rises above 50°C during summer and the relative humidity is above 50% during most part of the year. Daily fluctuations in the temperature can be 20°C during hot weather, while the relative humidity can vary from 40 to 100% within a 24-hour period. Dust storms are frequented all year around, but more so during long summers. Atmos- phere contains pollutants like sulphates from the local oil and petrochemical industry accompanied by high chloride levels from the Arabian Gulf. The region also has a high rate of sea salt deposition. According to an estimate, the salt and sulphate concentrations in the atmosphere in Jubail are about 500 and 100 times greater than that at Long Beach, Cali- fornia respectively [11]. Moreover, sulphur dioxide and organic carbonaceous deposits from burning fuel increases the corrosion tendency of the atmosphere in the Gulf region. The soil in Jubail is also considerably corrosive [1,2] due to low groundwater level and high salt concentration of ground water. This combination of industrial and coastal atmosphere gives rise to specific exposure conditions that need to be eval- uated in order to determine the viability of the use of structural components and engineering materials in such an environ- ment. The present study explores the corrosivity of environ- ment and its effect on the long-term corrosion behaviour of two commonly employed engineering materials i.e. stainless steel types 304 and 316, in the local industry. Exposure of SS samples was performed in atmospheric, underground and sea- water splash zone for a period of 15 months. © 2017 Institute of Materials, Minerals and Mining Published by Taylor & Francis on behalf of the Institute CONTACT Anwar Ul-Hamid anwar@kfupm.edu.sa CORROSION ENGINEERING, SCIENCE AND TECHNOLOGY, 2017 VOL. 52, NO. 2, 134–140 http://dx.doi.org/10.1080/1478422X.2016.1213974