Solid Wire Electrodes for GMAW

Solid wire electrodes are available in a range of sizes to be used with
various ferrous and nonferrous metals. The surface of filler wires for mild
and low alloy steels is usually protected with a thin layer of copper coating. The copper coating also acts as a lubricant during the welding
operation, when the wire moves through the contact tube in the welding
gun.

The solid wire electrodes are generally quite smaller in diameter than those used for shielded metal arc welding and submerged arc welding. Wires usually range in size from 0.03" to 0.062" (0.8 - 1.6 mm) in diameter; however electrode diameters can be as small as 0.020" and as large as 1/8" (0.5 - 3.2 mm). The standard European welding wire diameters for gas metal arc welding, range from 0.6 mm to 3 mm, the most popular sizes being 0.8, 1 and 1.2 mm.

The welding position is important in the selection of the proper wire diameter; as a general rule smaller size wires are used for overhead and vertical welding.

Due to the small wire size and high current density used in gas metal arc welding, the filler metal melts at a high rate and there fore the feeding
rate of the wire ranges from 100 to 800 inches per minute (40 to 340
mm/sec). Because of this rapid welding and high feed speed the welding
wires should be fed continuously. This means that the wire should be properly spooled.

Various spools of different shapes and weights are being marketed. In Europe, both random and layer wound wires on either wire or plastic spools are provided. Smaller spools as well as drums are also offered.

As the gas metal arc welding electrode wires have a small diameter, the surface/volume ratio is high and, therefore, the cleanness of the wire surface is very important. Residues of drawing compounds, lubricants and impurities such as oxides or other foreign matters on the surface of the wire can cause porosity and cracks in the welds.

The most commonly used specifications for Gas Metal Arc Welding wires are the European Norms (EN) and the AWS filler metal specifications.