IJRET: International Journal of Research in Engineering and Technology eISSN: 2319-1163 | pISSN: 2321-7308 _______________________________________________________________________________________ Volume: 04 Issue: 09 | September-2015, Available @ http://www.ijret.org 23 EFFECTS OF WELDING CURRENT AND ARC VOLTAGE ON FCAW WELD BEAD GEOMETRY Memduh Kurtulmus 1 , Ahmet İrfan Yukler 2 , Mustafa Kemal Bilici 3 , Zarif Catalgol 4 1 School of Applied Sciences,Marmara University, Istanbul, Turkey 2 Technology Faculty, Marmara University, Istanbul, Turkey 3 School of Applied Sciences,Marmara Universit, Istanbul, Turkey 4 Technical Education Faculty, Marmara University, Istanbul, Turkey Abstract Flux cored arc welding(FCAW) process is characterized with its high deposition rate and productivity. Control of the operating parameters in FCAW is essential to obtain high production rates and good quality welds. Bead on plate welds were carried out on mild steel plates to study the influence of welding current and arc voltage on weld bead geometry parameters. The weld bead coss-sections were metallographically investigated. The effects of these welding parameters were evaluated by measuring penetration depth, reinforcement height, bead width, wetting angle, electrod deposit area and plate fusion area. The bead cross- section area and the weld shape factor were calculated from the measured results. The effects of welding parameters on weld bead geometry have been presented by histograms. Key Words: Flux cored arc welding, arc welding parameters, weld bead geometry, weld shape factor --------------------------------------------------------------------***---------------------------------------------------------------------- 1. INTRODUCTION Flux cored arc welding (FCAW) is a fusion welding achieved by an electric arc produced between a continuous filler metal electrode and the weld pool [1]. In this method the filler metal of tubular shape is continuously fed and has a fluxed core which provides shielding capabilities to the welding process with or without additional shielding from an externally supplied protection gas. The core is mainly formed by slag formers, deoxidizers, arc stabilizers, and alloying elements. FCAW method have received great attention from welders and contractors because flux cored wire have a lot of advantages such as outstanding productivity, high quality welds, deep penetration, spatter reduced welding behavior, higher deposition rates, high welding speed and cost advantages [2]. FCAW may be applied semi automatically or automatically. The FCAW process has become a very popular semiautomatic process for structural steel fabrication [3],shipyard Works [4] and repairs [5-7]. FCAW is also readily accepted for weld cladding [8,9]. The profile of a weld bead geometry and its geometry parameters are schematically shown in Figure 1[10]. Weld geometry parameters are represented by bead width (W), height of reinforcement (H), depth of penetration (D), wetting angle (θ), electrode deposit area (A d ) and plate fusion area (A m ). These parameters are measured on images of weld beads. The weld bead cross-section area (A t ) is calculated by adding the electrode deposit area to the plate fusion area. Many researchers accepted the ratio of weld penetration depth to the weld width (D/W) is an important parameter to describe the weld profile [11-13]. This parameter is named as weld shape factor [14]. The weld bead geometry is directly dependent on welding parameters [15]. The cross-sectional area of the bead detemines the cooling rate of the weldment [16]. Bead cross-sectional area [17] and the ratio of penetration depth to weld width [10] determine the residual stresses and cracking of the weldment. Due to the above reasons, the quality and mechanical properties of weldments are dependent on size and shape of the weld bead [18,19]. Welding parameters must be optimized in order to obtain a good weld joint with the required bead geometry and weld quality [20]. There are also several publications about optimizations of the FCAW process by weld bead geometry analysis [21-35]. In these studies especially the effects of FCAW welding current, welding speed, arc voltage, electrod angle and nozzle to plate distance were investigated. The effects of these welding parameters on weld penetration depth, weld width and weld cross-sectional area were determined. Fig-1: Geometry parameters of a bead on plate weld 10). A d : Electrode deposit area, A m : Plate fusion area, D: Penetration depth, H: Reinforcement height, W: Bead width, θ: Wetting angle In this study the influence of the welding current and the arc voltage on weld bead geometry were investıgated. These two welding parameters are very importanat in arc welding processes. In electric arc welding operations the heat input