Influence of the butt joint design of TIG welding on corrosion resistance of low carbon steel

Abstract

The aim of this work is to study the influence of the joint design of Tungsten Inert Gas welding (TIG) on the corrosion resistance of low carbon steel (type St-37). A single V-butt joints of a low carbon steel plates are performed by the Vangles 30°,45°,60° and square butt joint (angle 90°). Corrosion behavior of welded specimens in 3.5% NaCl solution was examined using Tafel polarization measurements. The corrosion behavior of the welded joint also is determined by open circuit potential (OCP) after that the cell’s current is changed due to increasing in potential by ±100. The results shown that the corrosion rate of welded joint with V-angle of 30° was found to be less than that of other angles (45°,60° and 90°). It found that the corrosion resistance of base metal was better than that of all welded joints. From the results of the microstructure it is evident that the joint design or geometric shape of weld has an important role in the welding process, when the preparation angle value of the weld gets bigger, the faults gets less due to increase of heat quantity in the weld region.