Studies on The Corrosion Behaviour of Mild-Steel Under Simulated Industrial Conditions

Abstract

Corrosion is the deterioration of physical properties of the material due to a reaction with its environment. It converts refined metal to their more stable oxide. Corrosion of the material will depends on mainly on two factors the material of construction and the environment present. In the present study, an attempt has been made to find the responsible factors in both the aqueous environment and the material of construction. Characterization of the water used for the quenching purpose in Rourkela Steel Plant, Odisha yielded the list of contaminants present in it. The effect of the presence of these compounds on the rate of corrosion has been studied by performing experiments using simulated quenching processing water which is later affirmed by the literature available. The reference level used for the study is taken from the reported literature values as well as from the obtained experimental results. The single effects as well as the combined effects of the water quality parameters are also taken to account for the corrosion study. An inhibitor is used to check the inhibiting efficiency of the selected chemical. The surface morphology has been studied by SEM and XRD analysis which detects the type of corrosion taking place. EDX analysis of the quenching water establishes the presence of oxygen, carbon and sulphate. XRD analysis infers the formation of various corrosion products such as FeO, Fe2O3and Fe3O4 etc. Literature suggests parameters such as hardness, BOD, COD and presence of various elements such as chloride, sulphate, nitrite, etc. also affects the corrosion rate of a material. On characterisation of the quenching water, the following parameters were obtained: BOD 110.56, DO 10.00, COD 508.80, Hardness 400.96, phenol 70.08, sulphate 7.68, Chloride 223.00, Nitrite 0.20, Ammonia 116.80, and finally organic nitrogen as 246.60 mg/l. Another important parameter which plays a role in the rate of corrosion is the formation of passive layer on the surface of the metal. A wide range of chemical compounds are known to inhibit corrosion in various environments. In the present work, aniline was studied to determine its corrosion inhibition efficiency. The results show that aniline was highly efficient against corrosion due to chlorides while least efficient against corrosion owing to phenols. Aniline was found to be suitable for low-temperature range and lost its knack as the temperature was increased. Thus the problem of corrosion can be under took by utilizing the information obtained from the present investigation