Mechanics, Materials Science & Engineering, May 2017
ISSN 2412-5954
Kinetics of Corrosion Rate of Carbon Steels in Different Acidic Media9 Ashok Kumar1,a 1
Assistant Professor in Physics, Y.S.R. Engineering College of Yogi Vemana University, Proddatur, India
a
drashok.yvuce@gmail.com DOI 10.2412/mmse.25.49.44 provided by Seo4U.link
Keywords: carbon steels, corrosion, acid media, concentration variation, weight loss.
ABSTRACT. The corrosion properties of carbon steels in various acidic media sulfuric acid, nitric acid, hydrochloric acid and hydrofluoric acid has been studied. This paper also discussed about the corrosion behavior of mild steel in two different concentrations. Carbon steels were exposed to different acid environments in different intervals of time and corrosion rates were evaluated using weight loss method. It was evident from the results that the corrosion rate of the carbon steels in all the acidic media are increased with time of exposure. The carbon steels shows higher corrosion rates in nitric acid medium than compared to other acidic media. This can be attributed to strong oxidizing property of nitric acid and larger potential to break down the passivating film formed on the surface of the sample. The mild steel sample was also exposed to different concentrations of nitric acid medium. The results shows that the corrosion rate was increased with increase of concentration possibly attributed to increase in the rate of reaction on the surface of the sample which further reduces the energy barrier.
Introduction. Carbon steel is known to be the best preferred materials for industry as it has many industrial applications. It is easy availability, excellent physical properties, stronger and more workability than cast iron, low cost, uncomplicated fabrication made it to use in different applications like pipeline materials in oil and gas industry water pipe lines [1, 2], cooling water systems [3], boilers etc. However, the acids containing chloride, sulphide and so on introduces different forms of corrosion. Among the different acids, hydrochloric acid is the most difficult to handle from the keeping in view of corrosion and materials of constructions. Extreme care is required in the selection of materials to handle the acid by itself, even in relatively dilute concentrations or in process solutions containing appreciable amount of hydrochloric acid. This acid is very corrosive to most of the common metals and alloys [4]. Corrosion of metal components has been recognized as a major problem in many engineering applications. Failure of engineering systems due to corrosion is a common failure due to mechanical causes such as brittle fracture and fatigue. Steel is one of the major construction material, which is extensively used in chemical and allied industries for the handling of acid, alkali and salt solutions. Selection of materials plays a key role in handling the acid even in relatively very low concentrations. The acids are very corrosive to most of the common metals and alloys. Metals are exposed to acids in many different ways and for many different reasons like acids pickling, acid descaling, industrial acid cleaning and oil well acidizing in order to stimulate of oil well [5]. The corrosive nature of acids also has its applications include chemical cleaning and processing, acid treatment of oil wells and other applications. To control the corrosion, good understanding of the effect of operating conditions such as different types of acids, concentrations and different heat treatment procedures on the corrosion behavior is required. Therefore, this work aims to study free corrosion behavior of different carbon steels under different dilute acidic solutions like sulfuric acid (H2SO4), hydrochloric acid (HCl), nitric acid 9
s is an open access article under the CC BY-NC-ND license http://creativecommons.org/licenses/by-nc-nd/4.0/
MMSE Journal. Open Access www.mmse.xyz
63