Papers by Keyword: Weld Pool Geometry

Abstract: Gas Tungsten Arc Welding (GTAW) involves several process parameters. In Pulsed Current GTAW frequency of pulse and pulse to time ratio differentiates the characteristics of weld pool geometry of from GTAW. In the present work a simple heat transfer model for Pulsed Current GTA welding was developed and the weld pool dimensions were experimentally verified with AISI 1020 steel. Relationship between speed and pulsed current frequency on weld pool dimension was studied. Weld pool dimension of pulsed and non-pulsed GTAW is studied.

Abstract: Skilled welders can estimate and control the weld penetration based on weld pool observation. This implies that an advanced control system could be developed to control the penetration by emulating the decision making process of the human welder. In this paper a nonlinear dynamic model is established to correlate the process inputs (welding current and traveling speed) and weld penetration in Gas Tungsten Arc Welding (GTAW). An innovative 3D vision sensing system capable of measuring the weld pool characteristic parameters in real-time is utilized. Dynamic experiments are conducted under various welding conditions. Dynamic linear model is first constructed and the results are analyzed. The linear model is then improved by incorporating a nonlinear operating point modeled by Adaptive Neuro Fuzzy Inference System (ANFIS). It is found that the penetration state can be better modeled by the proposed ANFIS model.

Abstract: The determination of the temperature distribution of submerged arc-welded plates is essential when designing submerged arc-welded joints. The key role for the change of weld-bead geometry dimension, thermal stress, residual stress, tensile stress, hardness, etc., is heat input. Heat input is the function of temperature distribution of submerged arc welded plates. An attempt is made in this paper to find the analytical solution for a moving heat-source of egg-shape in a semi-infinite body. The considered modes of heat transfer for this study are conduction and convection. The solution has been obtained by integrating the instantaneous point heat source throughout the heat source volume. Very good agreement between the predicted and measured transient temperatures at various points on submerged arc-welded plates has been obtained. The predicted yield parameters are also in good agreement with the measured values.