A COMPARATIVE STUDY OF THE EFFECT OF SEAWATER CORROSION ON 0.34% AND 0.36% CARBON STEEL COMPOSITIONS

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e-ISSN: 2582-5208 International Research Journal of Modernization in Engineering Technology and Science Volume:02/Issue:11/November -2020

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A COMPARATIVE STUDY OF THE EFFECT OF SEAWATER CORROSION ON 0.34% AND 0.36% CARBON STEEL COMPOSITIONS Ajah U. C.*1, Nnam R. E.2, Onwuka I. N.3, Arinze C. V.3, Ezeali O. S.1 *1,1Department

of Civil Engineering Technology, Akanu Ibiam Federal Polytechnic Unwana.

2Department 3Department

of Food Technology, Akanu Ibiam Federal Polytechnic Unwana.

of Mechanical Engineering Technology, Akanu Ibiam Federal Polytechnic Unwana.

ABSTRACT In this research, the effect of seawater corrosion on 0.34% and 0.36% carbon steel compositions was investigated. 120mm of steel rod were used for each of 0.34% and 0.36%. Two samples of length 10mm and diameter 10mm were gotten from each steel rod. Also two samples of steel rod with length 50mm and diameter 10mm were also gotten from each of the steel rods of 0.34% and 0.36% composition. For each steel composition, one sample of length 10mm length and one specimen of 50mm length were heat treated. The heat treated sample of length 10mm and another one not treated with but of the same length and diameter were exposed to seawater to evaluate the effect of seawater corrosion on each of the steel rod compositions. The heat-treated specimen of 50mm length and one corresponding sample that was not heat treated for each steel composition was used for the micrography of this research. The result showed that the corrosion rate of 0.34%C changed from 0.21633mmpy to 0.15711mmpy on exposure to seawater. It also shows that the corrosion rate of 0.36%C changed from 0.17889mmpy to 0.00024519mmpy on exposure to the same seawater condition. The result showed that heat treatment improves the corrosion- resistant properties of both steel compositions more than that of the untreated carbon steel of same composition. The results also show that 0.36%C composition has a better corrosionresistant ability. Keywords: corrosion, seawater, carbon steel, heat treatment; 0.34%C composition, 0.36%C composition.

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INTRODUCTION

One reason for the wide use of metallic materials in various engineering fields lies in the versatility of the mechanical properties they possess (Oluyemi et al 2011). Steel is an alloy of iron and carbon. Steel with low carbon content has the same properties as iron, soft but easily formed. As carbon content increases, the metal becomes harder and stronger but less ductile and more difficult to weld (Smith and Hashemi 2006; Daramola et al., 2010). Medium steel is steel with composition of carbon between 0.3 to 0.7%C and which are used in the reinforcement of building, manufacturing of food process equipment and production of machine parts such as nuts and bolts, shafts and gears (Ashby and Jones 1994). Carbon steel can be described as a steel in which the main interstitial alloying constituent is carbon and ranges from 0.12 – 2.0%. Medium carbon steels are the only types of plain carbon steels which can undergo both alloying and heat treatment processes to confer desirable properties on it. Each carbon steel composition has a unique micro-structure and property. Carbon steel is by far the most important alloy used as structural members in engineering applications (Degarmo, 2003; Rajan, et al., 1989). The behavior of carbon steel is the fundamental parameter that determines the design and applicability of structural steel in engineering such as reinforcement members in structures. This is because they can also be easily bent or pre- stressed. They can also be used where small radii bends are necessary. As afore-mentioned, the mechanical properties of carbon steel like high tensile strength, yield strength, percentage elongation, ductility, hardness, wear resistance as well as its chemical properties such as corrosion resistance increases are improved significantly by heat treatment process and/or alloying (Daramola et al 2013; Larrabee, 1958; Afolabi et al 2011). Heat treatment of carbon steels is one of the most important determining factors as to how carbon steels perform when used in different applications. Engineering materials, mostly steel, are heat treated under controlled sequence of heating and cooling to alter their physical and mechanical properties to meet www.irjmets.com

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