Atmospheric Corrosion of Stainless Steel 304

Abstract

Metal Materials are used for the construction of structures in sub-Saharan Africa. The typical welding and joining techniques are the Metal Inert Gas, Tungsten Inert Gas and Arc welding. Atmospheric corrosion is a serious problem and if not properly maintained, they can quickly become liabilities because of corrosion-generated leaks and service interruptions. Although the study of the corrosion are often simplified, the impact of the tanks for maintaining an adequate quality of water in the network without corrosion is of paramount. Three samples were exposed for nine days to outdoors atmospheric conditions (C3 corrosivity) and then to an immersion test for 30 days equivalent to 120 cycles according to the ASTM G50 and ASTM G44 standards. The weight-loss method was used for the measurements of weight loss of the material as a function of time. The samples were cut and welded using arc welding, metal inert gas and tungsten inert gaz. The welded samples were compared, and the result of the corrosion rate performed. The corresponding rate of corrosion from experiment for arc welding and Metal Inert Gas was 0.01 mm/y and for Tungsten Inert Gas was 0.004 mm/y. The corrosion resistance of stainless steel was explained by the very thin passive layer that prevents the iron from corrosion. The formation of this passive layer is closely related to the chromium content of the steel with a minimum of 10.5% Chromium produces a thin layer of oxide on the surface of the steel. Increasing the amount of Chromium gives an increased resistance to corrosion. Metal alloys undergo uniform chemical corrosion that attacks surface evenly. Therefore, the loss of mass per unit area and per unit of time can be determined during the immersion test., For each of the three samples, measurement of the weight loss was done after 40, 80 and 120 cycles for a period of 30 days. The result of this study showed that the arc weld and the metal inert gas corroded faster and has a higher corrosion rate on the weld zone, whereas the tungsten welding was found to be the most resistant against corrosion attack.