Usually carbon steel, stainless steel, or low alloy steel pipes.

Gravity is the welder's biggest opponent in the 5G position. During the overhead portion at the bottom of the pipe, the molten puddle wants to sag or "drip," which can lead to lack of fusion or internal concavity. To combat this, welders must use a tight arc and adjust their rod angle constantly.

The worst part of any 5G weld is the bottom—the 6 o’clock position. Overhead. You have to lie on your back or, as Carver did now, contort your body sideways, propped on one elbow, looking up at the joint like a dentist peering into a rotten tooth. The molten metal hangs upside down. It falls toward your face. Every instinct screams at you to pull away. You don’t.

In a 5G setup, the pipe is fixed parallel to the ground. The welder usually starts at the bottom of the pipe (the 6 o'clock position) and works upward toward the top (the 12 o'clock position) for vertical-up welding. Conversely, some procedures specify vertical-down welding, starting at the top and moving to the bottom.

Mastering the 5G Welding Position: Techniques, Challenges, and Applications