Views: 0 Author: Site Editor Publish Time: 2025-11-17 Origin: Site
The number-letter code tells a welder exactly how the joint is oriented:
The Number refers to the welding position (1=Flat, 2=Horizontal, 3=Vertical, 4=Overhead).
The Letter "G" stands for Groove Weld.
1. 1G (Flat Position) / PA
Orientation: The pipe or plate is placed so the weld is on top, and the welder performs the weld from above.
Key Challenge: This is the easiest position. Gravity works in the welder's favor, pulling the molten metal into the joint. It allows for the highest deposition rates and best quality with the least effort.
Common Use: Fabrication in a shop where the workpiece can be positioned or rotated for flat welding.
2. 2G (Horizontal Position) / PC
Orientation: The weld axis is horizontal, and the weld face is vertical.
Key Challenge: Gravity tries to pull the weld metal downwards. The molten pool can sag, creating a thicker weld at the bottom and a thinner one at the top. The welder must carefully control the arc and travel speed to create a uniform bead.
Common Use: Welding a joint on a vertical surface, like a seam on a storage tank or a large structural column.
3. 3G (Vertical Position) / PF
Orientation: The weld axis is vertical.
Key Challenge: Gravity pulls the metal straight down. This requires specific techniques to counteract it:
Vertical Up (3G Uphill): Welding from the bottom up. This technique provides deeper penetration and is stronger, used for thicker materials.
Vertical Down (3G Downhill): Welding from the top down. This is faster but gives shallower penetration, used for thinner materials to prevent burn-through.
Common Use: Shipbuilding, structural steel erection (e.g., columns), and large storage tanks.
4. 4G (Overhead Position) / PE
Orientation: The weld is performed from the underside of the joint. The welder holds the torch above their head.
Key Challenge: This is the most difficult position. Gravity is constantly trying to drip the molten weld metal out of the joint. It requires excellent arc control, proper amperage settings, and a very steady hand to prevent defects and ensure fusion.
Common Use: Welding on the underside of structures, such as bridges, ship decks, or overhead beams that cannot be moved.
For more welding solutions, you can leave message to us here.
