Experimental Investigation of Welding Parameters and Simulation of Heat and Fluid Flow in Weldments

Abstract

Welding is one of the most versatile processes for joining components in the industrial and manufacturing sectors. Hence, the critical study of welding parameters and the heat and fluid flow behaviour is deemed necessary. In the current work, an experimental investigation of the effect of welding parameters on the mechanical properties of the welded joints and simulation of heat and fluid flow within the weldments were presented. Low carbon steel was welded using a shielded metal arc welding process (SMAW) and a single V-grooved butt joint was produced. Welding currents of 100 amperes and 115 amperes were varied for different electrode types of E 6013 (ENL), E 6013 (AWS) and E 7018 for the welding process. Tensile and hardness tests were carried out on the welded joints. X-ray diffraction analysis was carried out to ascertain the phases present within the weld area. Additionally, the heat and fluid flow patterns within the weld pool were studied using ANSYS Fluent. The results show that there are significant effects of welding current and electrode type on the tensile strength and hardness of the weldment. For all the samples analysed, electrode type rather increase in current improved the mechanical properties significantly. The optimum tensile strength for the SMAW process was produced by the welding electrode E 7018 at 115 A with a strength of 652 MPa. The lowest value of tensile strength was 491 MPa for E 6013 (AWS). The highest hardness was produced by E 7018 electrode at 115 A with a value of 177 HV while the lowest was 122 HV for E 6013 (AWS) electrode. Heat transfer analysis showed that the maximum temperature value of 1867 K was obtained close to the arc region. Due to the narrow area of weld pool occasioned by large thermal gradient and rapid solidification, the fluid flow region reported was small and the supposed recirculating flow cells and loops were not well developed.