7 - Gas metal arc welding

Abstract

This chapter highlights the implications of the gas metal arc welding (GMAW) process developments. Due to its high operating factor and deposition rate, GMAW has the potential to improve productivity over that obtained with the GTAW and SMAW processes. Although the requirement to exploit the economic benefits of the process has led to a clear trend toward greater use of GMAW worldwide, it has in the past proved difficult to obtain reliable quality. Therefore, the main thrust of development has been to improve control and achieve more consistent quality. The way in which material is transferred from the tip of the consumable electrode into the weld pool has a significant influence on the overall performance of GMAW: it affects process stability, spatter generation, weld quality, and the positional capabilities of the process. The various natural types of transfer have been classified into groups. The chapter presents a simplified basic classification of metal transfer in GMAW. It also discusses globular drop transfer, globular repelled transfer, drop spray transfer, dip transfer, and several variations of normal transfer.