Modeling of MIG/MAG welding with experimental validation using an active contour algorithm applied on high speed movies

Abstract

International audienceThis paper investigates some issues in physical modeling of metal inert gas/metal active gas (MIG/MAG) welding process in the short arc mode. In this mode, a metal supply is molten in the arc state and then transferred to the weld pool during the short-circuit state. A hybrid model having two distinct continuous states whose switchings are controlled by two guard conditions is proposed. Due to the complexity of the physical phenomena involved in the welding process, simplifications are used to obtain a model accounting for the main physical contributions but simple enough to yield an efficient, fast and numerically tractable simulator which can be used intensively for evaluating different control strategies. In an attempt to validate the proposed model, different measurements have been made including supply voltage and current sampled synchronously with high speed digital video. In order to extract some relevant quantities representative of the metal transfer from image sequences, an active contour algorithm is developed and tested. The effectiveness of the proposed model in the prediction of major tendencies of a welding process, especially in the arc state, is shown using experimental data. Some limitations of the model during the metal transfer are also stressed and possible remedies are then proposed

Untitled

“…Gas inert yang umumnya gas berbasis argon (pengelasan MIG) sedangkan gas aktif yang umumnya gas berbasis CO2 (pengelasan MAG) digunakan sebagai plasma untuk pencetus busur listrik dan sebagai gas pelindung untuk logam pada temperatur tinggi untuk menghidari kontaminasi dengan oksigen dan nitrogen. Generator pengelasan mensuplay energi listrik yang dibutuhkan untuk mencairkan logam dan pencetus busur dan menjaga kesinambungan aliran kawat dan benda kerja yang dilas [13]. Las SMAW adalah pengelasan dengan elektroda terbungkus dimana pelindung logam las adalah selaput pada elektroda, kekurangan dari las SMAW adalah pengelasannya yang potensi cacat las lebih besar karena pengaruh dari perlakukan elektroda seperti elektroda yang lembab dan harus dipanaskan, pengaruh coating dan panjang elektroda yang terbatas sehingga kurang efektif untuk proyek pengelasan, sedangkan las MAG elektrodanya merupakan gulungan tanpa ada pembungkus dengan menggunakan gas sebagai pelindung sehingga elektrodanya mudah dalam penggunaannya, dan bisa mengelas tanpa pergantian elektroda seperti SMAW untuk pengelasan material ukuran panjang.…”

Modeling and simulation of the metal transfer on GMAW-S process

“…Efforts are focused on addressing the phenomena involved at the metal transfer time during a short circuit. The model presented takes as reference the work developed by Doodman [18] and Planckaert et al [12] and considers its application for orbital welding.…”

“…3into the current I that flows through the drop, we obtain Eq. (4) corresponding to the electromagnetic force; 0 is magnetic permeability ( 4 × 10 −7 N/A 2 ), r d the droplet radius, r e is the electrode radius, and f z is the variable term of the electromagnetic force [12,19] as indicated in Eq. (5).…”

“…where corresponds to the linear resistivity and C 1 and C 2 are constants that describe the electrode heating, as results of arc heating and the Joule effect, respectively [12].…”

“…In the same year, Modenesi et al [11] developed a numerical model to calculate the temperature along the electrode during GMAW-S welding. Planckaert et al [12] presented a study proposing a training and mass transfer model for the GMAW-S process in which the authors emphasize the need to use different models for both the short circuit and the arc phase in the metal transfer cycle. Modenesi et al and Zuo et al [11,13,14] presented a mathematical model capable of simulating the electrical aspects of GMAW-S welding.…”