The Influence of Arc Welding Process on the Mechanical and Microstructural Characteristics of Low Carbon Steel in a Corrosive Environment

Abstract

The study is fundamentally geared toward the investigation of the influence of Manual Metal Arc (MMA) welding on the mechanical and microstructural properties of low carbon steel immersed in a 0.5 M nitric acid environment having a pH of 0.3. The corrosion and mechanical behavior of the substrates are investigated prior to and after 336 h of immersion in the test environment. The outcome of the experiment shows that the structural integrity of the immersed substrates is affected due to corrosion in the test environment. Prior to immersion, the bending resistance is seen to decrease at the welded joints relative to the blank sample and then decrease further after immersion in the test solution respectively as 3.95, 3.53, and 4.21KN. Similarly, the tensile strength of the immersed substrate decreases as compared to the unexposed and blank samples; exposed to test environment (30.60%), welded unexposed to test environment (33.25%) and for the control sample (36.33%). Furthermore, the hardness value is observed to be higher at the heat-affected zone (HAZ) of the test substrate than at the weldment and parent metal, respectively, as 11.3, 17.7, and 15.7HV. Optical micrographs prior to and after immersion have evidently revealed that heat input during welding has caused recrystallization leading to coarser grains at the HAZ.