Experimental Analysis of Droplet Gas Interaction During GMAW Process

Quality of GMAW is closely related to the behavior of the droplet from its detachment from the wire to its impingement to the weld pool. The behavior of the droplet is often investigated through simulation [1]. Jones [2] developed experimental technique to study the detachment of a droplet from the wire and study the influence of parameters.

In the present research, an experimental methodology based on high speed imaging and contour detection was developed [3]. The images are synchronized with the current and arc voltage process. The automatic detection of contour allows to follow the shape for each image and to appreciate the evolution of the liquid metal for each droplet.

The methodology is then applied for a set of welding parameters and two different gas (100% Argon and 92% Argon-8%CO2), in order to see how the metal transfer is modified. The results allow to see and measure the influence of gas on the metal liquid droplet detachment and free flight motion for each period on the base of these data. It is then possible to make statistics and to propose a criteria to qualify the quality of the transfer.

[1] Fan, Kovacevic, Droplet Formation, Detachment, and Impingement on the

Molten Pool in Gas Metal Arc Welding , , 1999 Metallurgical And Materials Transactions B, p791- 801

[2] Jones, Eagar, Lang, A dynamic model of drops detaching from a gas metal arc welding electrode. J.Phys.D: Appl Physics, 1998, p107-123

[3] Romero, Chapuis, Bordreuil, Soulié, Fras, Image Processing and geometrical analysis for

profile detection during P-Gas Metal Arc Welding , submitted, Measurement Science and Technology.

[4] Chapuis, PhD Thesis de l'université de Montpellier 2, France, http://www.theses.fr/2011MON20018