High-performance GMAW process for deep penetration applications

This study approaches conflicting aspects of high-performance MIG/MAG associated with penetration. It demonstrates that a simpler version with voltage control enables the obtainment of good results as long as some premises, related to the power source, are maintained. The molten pool in this case is a cavity in the piece, which is caused by a condition referred to as buried arc. In this technique, a short circuit is imminent, and dynamic characteristics are required of the power source employed, so that the arc stability is maintained through a change in the value of the current at different rise and fall rates. The use of different gas mixtures was also analyzed, including the version referred to as T.I.M.E. Even though it influenced the geometry of the melted zone, this gas mixture does not provide a significant improvement in the buried arc in relation to other mixtures. A comparison, in terms of the dynamic morphology of the pool, between the process with voltage control and the variant Rapid Arc (pulsed current) also shows the efficiency of the simpler version for a deep penetration. The employment of less expensive mixtures, such as 50% of CO2 in argon, technically achieves the same objectives in high-performance welding.