MODELING OF WELD QUALITY OF PULSED TIG WELDED ALUMINUM PLATE

Abstract

The information of variable input parameters plays an important role in the precise control of the weld bead geometry. Pulsed TIG welding is a method of controlled heat transfer, in which the are current is maintained at a value high enough to permit metal transfer and once the metal is transferred the current is reduced to low value which used only to initiate the arc, so only the periodic injection of high current pulses allows the metal to be transferred. Parameters of these current pulses, such as peak current, base current, and pulse width and pulse frequency have a distinct effect on the characteristics viz., stability of the arc, weld quality, bead appearance and weld bead geometry. Improper selection of these pulse parameters may cause weld defects including irregular bead surface, lack of fusion, undercuts, and bum-backs and in major it reduced the overall quality. Therefore, it is important to select a proper combination of parameters of the pulsed current for welding, which will ensure that the process gives proper results in all the above aspects. However, arriving at such a combination of parameters without a rational base would be only a matter of chance with a fairly low probability for achieving desirable weld properties, since the complexity and interdependence of pulse parameters involved in this process. Hence, a detailed study is essential to arrive at a method of predicting the conditions that will give a good weld quality. This report depicts various aspects of the pulsed TIG welding, the effects of individual pulse parameters and these features are then used to quantify weld quality of pulsed TIG welding Aluminum plate. A good agreement is found between the experimental observations and result obtained through modeling. The results of the present investigation shows that the developed model is capable enough to identify qualitative response of Pulsed TIG welded Joints of thin plates and the combined effect of parameter on the overall weld quality. The simplicity and effectiveness of developed model makes it user friendly and it ma e finer researches. In this work, Modeling of weld quality model for Pulsed TIG thin-Aluminum sheet is reported. This model is based upon combination of analysis of variance, multiple regression analysis and aggregate quality index method (AQIM). Thin aluminum plates have been joined by Pulsed TIG welding by varying the process parameters and corresponding features on the weld pool geometry i.e., the Front depth, back height, front width and back width are presented.