Overhead Welding Position (4G) is one of the hardest position in plate welding. Overhead position is used on fixed structure wherein you don’t have any choice as a welder bu to weld it overhead. Some contractors, espcially those who have a neophyte welders tend to postion their structrure either in vertical or horizontal postion for easiness and to avoid the difficult overhead postion.
Once you are qualified to 4G, you can easiy qualify in 3G and 2G. If you are qualified in 2G, 3G and 4G, then you can weld structural in all position (groove or fillet).
You can also learn the pipe welding easily if you know how to weld in overhead postion since pipe welding includes overhead, vertical and horizontal position.