Semi-automatic arc welding process

The aim of this article is to present the semi-automatic arc welding process, also known as MIG/MAG (Metal Inert Gas/Metal Active Gas). This process is extremely widespread in industry, thanks to its flexibility, versatility and productivity. It can be used for joining thin sheet metal, or for multi-pass welding of thick parts. The MIG/MAG process is mainly used in the transport, energy (pipeline welding, for example) and structural steel industries. Mainly used for assembling steel and aluminum alloys, it is potentially applicable to all alloys. The technology can also be used for welding and brazing, for reloading worn parts and for additive manufacturing. The article describes the equipment and consumables required for semi-automatic welding. It describes metal transfer methods and their applications. It also lists the main derivatives of the process (pulsed current, flux-cored wire and multi-cathodes). Finally, the main defects that can occur during welding are discussed, as well as the health and safety rules applied to semi-automatic welding. Examples of edge preparation are provided at the end of the article.

This article is not intended to deal with arc welding in general. For information on this subject, please refer to the article on arc welding [B 7 730] .