Corrosion Rate

Low carbon sheet metals are one of the widely used materials in the industrial sector, it will have a frequent contact with different chemicals, due to relative availability, its cost and the like. The main drawback of this metal is it corrodes easily when exposed to different environment. The research aims at investigating the corrosion rate of low carbon steel, specifically sheet metals in the acidic medium (Nitric Acid, sulphuric acid and hydrochloric Acids each with concentration of 1.0M, 1.5M and 2.0M). The sample coupons with known weight were immersed in the sample media (Nitric Acid, Sulphuric acid and Hydrochloric Acids) for five days and the weight loss measurement were taken with the interval of 24hrs. Different research revealed that the presence of corrosion of low carbon sheet metals in HCl, HNO 3 and H 2 SO 4 solutions are credited to the presence of water, air and H + which accelerated the corrosion processes. To fulfil the aim of this research weight loss was calculated from the measured weight values. And the calculated value shows, the rate of attack increases with increase in time and molar concentration of the acids, the weight loss and corrosion rate becomes high in Nitric acid and the least in hydrochloric acids. Finally, corrosion in Nitric acid exhibits colourful appearance due to the evolution of Nitrogen (II) oxide gas. I. INTRODUCTION Low carbon steel is one of the most important materials that meet the strength requirements because most of its properties like its optimal strength to weight ratio, good cost to weight ratio, availability, ability to be readily supplied at relatively cheap price in range of different product forms with useful range of materials properties, possibility of enhancing desired mechanical properties by heat treatment, worldwide existence of abundant quantities of iron ore with in earth crust from which steel originates and possibility to produce the alloy from the ore using relatively economical extraction, refining alloying and fabrication, make the steel to be selective for structural works [1]. Corrosion of low carbon steel especially on sheet metals and the formation of corrosion products like iron oxides is one of the factors that obstruct the wide range in usage. Corrosion is believed to be an abiotic process of chemical reactions. It was generally agreed by most of the researches that carbon steels are generally attacked by uniform corrosion or general corrosion. Corrosion can be arise on low carbon due to a number of variables and complicate the course of corrosion in different ways such as chloride, sulphate, humidity and temperature [2]. So on time monitoring and inspection is required to alleviate the wide range of destruction and to propose the mechanisms as well as to take an on time action. This work aims at examining the corrosion rate of low carbon sheet metals in the acidic medium using gravimetric method. II. MATERIALS AND METHODS Materials used for this work were low carbon steel prepared in the mechanical workshop of Hawassa University in Hawassa Ethiopia. The chemical compositions of these materials are as shown in Table 1. The samples are sheet of metals with1 mm thickness was mechanically press-cut into 5 ×5 cm coupons and perforated at the center with holes to allow the passage of threads.