Modelling and Optimization of Corrosion Rate in Mild Steel Weld Joints Using Response Surface Methodology

Abstract

Corrosion is a natural phenomenon that occurs in metal or material. The various form of corrosion includes Uniform, galvanic, crevice, pitting and intergranular corrosion. The effects of corrosion affect the quality of the welded joints, welded structure and it service life of the welded structures. The aim of this study is to develop a model that can reduce the effects of corrosion on mild steel weld joints using response surface methodology. Design of Experiment was conducted with current, voltage and gas flow rate as the input parameters and corrosion rate as the response. Twenty (20) experimental runs was generated by the design expert software adopting the central composite design (CCD). Mild steel pipe was cut into dimension 40mm in length, 12mm diameter and 3mm thick using power hacksaw, before carrying out the welding. The response was measured after the experiment which is the rate of corrosion and the Experimental results was analyzed using response surface methodology to model and optimized this response. Results showed that the current has a very strong influence on the rate of corrosion. From our findings, it was observed that corrosion rate of 2.95048mpy was minimum at a voltage of 18V, current of 120A and gas flow rate of 13lit/min.