Metal inert gas (MIG) welding is a form of arc welding, where a welding power supply is used to create a powerful arc of electricity that melts and fuses metal. In MIG welding, an inert gas is used to prevent contamination of the weld site. A wire is continuously fed into the weld, acting as both electrode and filler for the weld.
The 3G test requires you to create welds in three positions. A flat weld is constructed along a horizontal join, rather as if it were a ditch. A horizontal weld is different from a flat weld in that the outer surface of the weld faces sideways instead of upwards, although the join runs lengthwise. A vertical weld is constructed in an upright position.
The benefit of passing the 3G MIG Welding Certification test is that you gain a certification from the American Welding Association. This improves your employment prospects and qualifies you for more welding jobs.