Final answer:
The welding position notation "5G" is associated with pipe welding, where the pipe is horizontal, and the welding is done vertically around the pipe. It does not correspond to flat, horizontal, vertical, or overhead positions in plate welding terms.
Step-by-step explanation:
The welding position notation "5G" refers to a type of welding position. Specifically, 5G is a position used for pipe welding where the pipe is in the horizontal position and the welder welds in a vertical direction. 5G is not associated with flat, horizontal, or overhead positions in the traditional sense when we refer to plate welding positions. Instead, it is a position where the pipe cannot be turned and the weld is applied in a circular progression around the pipe, which means the welding is performed with the pipe axis horizontal and at the welder's chest level. Therefore, for the question regarding the material and position, 5G is related to pipe welding, and it doesn't directly correlate to any of the provided options a, b, c, or d, which refer to plate welding positions.