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An experimental study on optimizing for tandem gas metal arc welding process

Lee J. P., Park M. H., Kim D. H., Jin B. J., Shim J. Y., Kang B. Y., Kim I. S.

Journal of Achievements in Materials and Manufacturing Engineering

2015

Vol. 68, nr 2

72--79

Purpose: To enhance productivity and provide high quality production material in a GMA welding process, weld quality, productivity and cost reduction affects the number of process variables. In addition, a reliable welding process and conditions must be implemented to reduce weld structure failure. Design/methodology/approach: The research investigates the interaction between the welding parameters (welding speed, distance between electrodes, and flow rate of shielding gas) and bead geometry for predicting the weld bead geometry (bead width, bead height). Taguchi techniques are applied to bead shape to develop curve equation for predicting the optimized process parameters and quality characteristics by analysing the S/N ratio. Findings: The experimental results and measured error is within the range of 10% presenting satisfactory accuracy. The curve equation was developed in such a way that you can predict the bead geometry of constructed machinery that can be used for making tandem welding process. Research limitations/implications: In various industries the welding process mathematical model is not fully formulated for the process parameter and on the welding conditions, therefore only partial variables can be predicted. Originality/value: This paper focused on the anode-cathode distance that can prevent arc blow in tandem GMA welding process. We also analysed the welding quality characteristics according to the bead geometry and welding parameters through S/N ratio dependent on the welding speed and flow rate variation of shielding gas. Finally, a mathematical model being able to predict the welding quality based on the given welding parameters using statistical method has been developed.

A study on on-line mathematical model to control of bead width for arc welding process

Son J. S., Lee J. P., Park M. H., Kim D. H., Jin B. J., Ki K. S., Kim C. G., Kim I. S.

Archives of Materials Science and Engineering

2015

Vol. 72, nr 2

78--85

Purpose: Recently, not only robotic welders have replaced human welders in many welding applications, but also reasonable seam tracking systems are commercially available. However, fully adequate control systems have not been developed due to a lack of reliable sensors and mathematical models that correlate welding parameters to the bead geometry for the automated welding process. Design /meth o d o lo g y/ap p ro ach : In this paper, two on-line empirical models using multiple regression analysis are proposed in order to be applicable for the prediction of bead width. For development of the proposed models, an attempt has been made to apply for a several methods. For the more accurate prediction, the prediction variables are first used to the surface temperatures measured using infrared thermometers with the welding parameters (welding current, arc voltage) because the surface temperature are strongly related to the formation of the bead geometry. The developed models are applied to monitor and control the bead width as welding quality. Findings: The developed two on-line empirical models are able to predict the optimal welding parameters required to achieve desired bead width and weld criteria, help the development of automatic control system and expert system and establish guidelines and criteria for the most effective joint design. Research lim ita tio n s /im p lic a tio n s : This research was concentrated to develop on the on-line empirical models that can predict bead width in robotic GMA welding process. The developed empirical models can only be employed to control the bead width for butt welding. O rig in ality /va lu e : It has been realized that with the use of the developed algorithms, the prediction of bead width becomes much simpler to even a novice user who has no prior knowledge of the robotic GMA welding process and optimization techniques.

Numerical and experiment study of residual stress and strain in multi-pass GMA welding

Chand R.R., Kim I.S., Lee J. P., Kim Y.S., Kim D. G.

Journal of Achievements in Materials and Manufacturing Engineering

2013

Vol. 57, nr 1

31--37

Purpose: Recently, manufacturing industries have been concentrated on selection an optimal of welding parameter and condition that reduces the risk of mechanical failures on weld structures should be required in manufactory industry. In robotic GMA (Gas Metal Arc) welding process, heat and mass inputs are coupled and transferred by the weld arc to the molten weld pool and by the molten metal that is being transferred to the weld pool. The amount and distribution of the input energy are basically controlled by the obvious and careful choices of welding process parameters in order to accomplish the optimal bead geometry and the desired mechanical properties of the quality weldment. The residual stress and welding deformation have the large impact on the failure of welded structures. Design/methodology/approach: To achieve the required precision for welded structures, it is required to predict the welding distortions at the early stages. Therefore, this study represented 2D Finite Element Method (FEM) to predict residual stress and strain on thick SS400 steel metal plate. Findings: The experiment for Gas Metal Arc (GMA) welding process is also performed with similar welding condition to validate the FE results. The simulated and experiment results provide good evidence that heat input is main dependent on the welding parameter and residual stress and distortions are mainly affected by amount on heat input during each weld-pass. Practical implications: This present study on based on the numerical analysis using ansys software, for a thick multi-pass GMA welding. A birth and death technique is employed to control the each weld pass welding. Originality/value: The developed 2D multi-pass model employs Goldak’s heat distribution, to simulate welding on SS400 steel butt-weld joint with a thickness of 16mm. moreover the numerical results are validated with experiment results.