AN EXPLORATORY SEARCH FOR THE INFLUENCE OF THE CO 2 CONTENT ON THE GMAW METAL TRANSFER AND PROCESS STABILITY

Olga Liskevych¹; Americo Scotti¹

¹ Universidade Federal de Uberlândia

Resumo

Gas Metal Arc Welding (GMAW, or also known as MIG/MAG process) is nowadays the most widely used welding process. It uses continuously fed electrode as a filler metal. The arc is shielded from the atmospheric contaminations by an inert gas, active gas or inert/active gas mixture. The shielding gas plays an important role in the operational behavior of this process. According to the blend used for shielding, the transfer mode, penetration, bead geometry, arc burning stability, etc can be affected. One of the most popular mixtures is Ar+CO 2 , which is suitable for short-circuiting transfer welding. It is recommended to choose the content of CO 2 in this mixture according to the given conditions, for example, low content of CO 2 is used for thin plates and higher percent of CO 2 for thicker plates. One explains it with the fact that increasing CO 2 makes the arc hotter. Some engineers also say that this active gas makes the short-circuiting metal transfer more stable.

Palavras-chave: Gas Metal Arc Welding; influence of the CO2