Welding is often done on structures in the position in which they are found. Techniques have been developed to allow welding in any position. Some welding processes have all-position capabilities, while others may be used in only one or two positions. All welding can be classified according to the position of the work-piece or the position of the welded joint on the plates or sections being welded. There are four basic welding positions, which are illustrated in figures 6-30 and 6-31. Pipe welding positions are shown in figure 6-32. Fillet, groove, and surface welds may be made in all of the following welding positions.
Flat Welding Positions
In this position, the welding is performed from the upper side of the joint, and the face of the weld is approximately horizontal. Flat welding is the preferred term; however, the same position is sometimes called down hand. (See view A, figure 6-30 and view A, figure 6-31 for examples of flat position welding for fillet and groove welds).
Horizontal Welding Positions
The axis of a weld is a line through the length of the weld, perpendicular to the cross section at its center of gravity.
Fillet Weld. In this position, welding is performed on the upper side of an approximately horizontal surface and against an approximately vertical surface. View B, figure 6-31, illustrates a horizontal fillet weld.
Groove Weld. In this position, the axis of the weld lies in an approximately horizontal plane and the face of the weld lies in an approximately vertical plane. View B, figure 6-30, illustrates a horizontal groove weld.
Horizontal Fixed Weld. In this pipe welding position, the axis of the pipe is approximately horizontal, and the pipe is not rotated during welding. Pipe welding positions are shown in figure 6-32.
Horizontal Rolled Weld. In this pipe welding position, welding is performed in the flat position by rotating the pipe. Pipe welding positions are shown in figure 6-32.
Vertical Welding Positions
b. In vertical position pipe welding, the axis of the pipe is vertical, and the welding is performed in the horizontal position. The pipe may or may not be rotated. Pipe welding positions are figure shown in figure 6-32.