Weld Types and Positions
WELD TYPES AND POSITIONS
a. General. It is important to distinguish between the joint and the weld.
Each must be described to completely describe the weld joint.
There are many different types of welds, which are best described by their shape when shown in cross section.
The most popular weld is the fillet weld, named after its cross-sectional shape.
Fillet welds are shown by figure 6-24.
The second most popular is the groove weld. There are seven basic types of groove welds, which are shown in figure 6-25.
Other types of welds include flange welds, plug welds, slot welds, seam welds, surfacing welds, and backing welds.
Joints are combined with welds to make weld joints.
Examples are shown in figure 6-26. The type of weld used will determine the manner in which the seam, joint, or surface is prepared.
b. Groove Weld. These are beads deposited in a groove between two members to be joined.
See figure 6-27 for the standard types of groove welds.
c. Surfacing weld (fig. 6-28).
These are welds composed of one or more strings or weave beads deposited on an unbroken surface to obtain desired properties or dimensions.
This type of weld is used to build up surfaces or replace metal on worn surfaces. It is also used with square butt joints.
d. Plug Weld (fig. 6-28).
Plug welds are circular welds made through one member of a lap or tee joint joining that member to the other.
The weld may or may not be made through a hole in the first member; if a hole is used, the walls may or may not be parallel and the hole may be partially or completely filled with weld metal.
Such welds are often used in place of rivets.
A fillet welded hole or a spot weld does not conform to this definition.
e. Slot Weld (fig. 6-28).
This is a weld made in an elongated hole in one member of a lap or tee joint joining that member to the surface of the other member that is exposed through the hole.
This hole may be open at one end and may be partially or completely filled with weld metal.
A fillet welded slot does not conform to this definition. f. Fillet Weld (top, fig. 6-28).
This is a weld of approximately triangular cross section joining two surfaces at approximately right angles to each other, as in a lap or tee joint.
g. Flash Weld (fig. 6-29).
A weld made by flash welding (para 6-5 d).
h. Seam Weld (fig. 6-29).
A weld made by arc seam or resistance seam welding (para 6-5 b). Where the welding process is not specified, this term infers resistance seam welding.
i. Spot Weld (fig. 6-29).
A weld made by arc spot or resistance spot welding (para 6-5 a). Where the welding process is not specified, this term infers a resistance spot weld.
j. Upset Weld (fig. 6-29).
A weld made by upset welding (para 6-5 e).
Section IV. WELDING POSITIONS
GENERAL 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 workpiece 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 positions.
FLAT POSITION WELDING 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 downhand. (See view A, figure 6-30 and view A, figure 6-31 for examples of flat position welding for fillet and groove welds).
HORIZONTAL POSITION WELDING
The axis of a weld is a line through the length of the weld, perpendicular to the cross section at its center of gravity.
a. 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.
b. 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.
c. 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.
d. 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 POSITION WELDING a. In this position, the axis of the weld is approximately vertical. Vertical welding positions are shown in view C, figures 6-30 and 6-31.
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.
OVERHEAD POSITION WELDING In this welding position, the welding is performed from the underside of a joint. Overhead position welds are illustrated in view D, figures 6-30 and 6-31.
POSITIONS FOR PIPE WELDING Pipe welds are made under many different requirements and in different welding situations.
The welding position is dictated by the job.
In general, the position is fixed, but in sane cases can be rolled for flat-position work. Positions and procedures for welding pipe are outlined below.