3.welding term

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UNIVERSITY KUALA LUMPUR

MALAYSIA FRANCE INSTITUTE

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Welding Terminology

Fusion and Penetration TerminologyThere are also terms relating to the fusion and penetration of the weld metal into the base metal.

FusionRefers to the actual melting together of the filler metal and base metal, or of the base metal only.

PenetrationRelates to the distance that the weld metal has progressed into the joint.

The groove faceIs referred to as the fusion lace,because it will be melted during welding.

The weld interface

Is referred to as the boundary between the weld metal and base metal.

The depth of fusion

Is the distance from the fusion face to the weld interface. The depth of fusion is always measuredperpendicular to the fusion face.

Root penetrationIs the distance that the weld metal extends into the joint root.

The joint penetration

Is the distance the weld metal extends from the weld face into a joint, exclusive of any weldreinforcement.

Heat-affected zone (HAZ)The region defined as the portion of the base metal whose mechanical properties or

microstructure have been altered by the heat of welding, brazing, soldering, or thermal cutting.

Figure 1 Fusion Welds


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Figure 2 Incomplete Joint Penetration or Partial Figure 3 Heat Affected Zone

Joint Penetration

Weld Size Terminology

Figure 4 Joint Penetration

Figure 5 Unequal Leg Fillet Weld

To determine the size of a fillet weld, first establish whether the final weld configuration is

convex or concave. The weld profile is convex if the weld face exhibits some buildup, causing it

to appear slightly curved outwardly. This is referred to as the amount of convexity. Convexity in

a fillet weld is analogous with weld reinforcement in a groove weld. If the weld face is dishedin, the profile is determined to be concave.


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The theoretical throat

Is described as the distance from the beginning of the joint root perpendicular to the hypotenuse

(side of the triangle opposite the right angle) of the largest right triangle that can be inscribedwithin the cross section of a fillet weld. This dimension is based on the assumption that the root

opening is equal to zero. This is the minimum amount of weld considered when the designer

originally specifies a weld size.

The effective throat

Defined as the minimum distance minus any convexity between the weld root and the face of afillet weld. The effective throat takes into account any additional joint penetration which may

be present.

The actual throatis described as the shortest distance between the weld root and the face of a

fillet weld. The actual throat, takes into account both the joint penetration and any additional

convexity present at the weld face. For a concave fillet weld, the effective throat and actual

throat are equal, since there is no convexity present (see Figure 6)

Figure 6 Fillet Welds


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Weld Application Terminology

A weld passIs a single progression of welding along a joint.

Weld bead or weld layerWhich is defined as a stratum of weld metal consisting of one or more weld beads. A weld layer

may consist of a single bead or multiple beads (see Figure 7).

Figure 7 Cross Sectional Welding Sequence

Stringer bead

A type of weld bead made without appreciable weaving motion.

A weave bead

Which is defined as a type of weld bead made with transverse oscillation, results when thewelder manipulates the electrode laterally, or side to side, as the weld is deposited along the

joint. The weave bead is typically wider than the stringer bead. Due to the amount of lateral

motion used, the travel speed (as measured along the longitudinal axis of the weld) is less than

would be the case for a stringer bead (see Figure 8).

A backstep sequence

is a longitudinal sequence in which weld passes are made in the direction opposite to theprogress of welding.

A block sequenceIs a combined longitudinal and cross-sectional sequence for a continuous multiple pass weld in

which separated increments are completely or partially welded before intervening increments are

welded. With the block sequence, it is important that each subsequent layer is slightly shorter


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than the previous one so that the end of the block has a gentle slope. This will provide the best

chance of obtaining adequate fusion when the adjacent block is tilled in later.

Figure 8 Weld Beads

A cascade sequence

Is a combined longitudinal and cross-sectional sequence in which weld passes are made inoverlapping layers. This method differs from the block sequence in that each subsequent pass is

longer than the previous one (see Figure 9).

The chain intermittent fillet weldIs defined as having an intermittent weld on both sides of a joint in which the weld Increments

on one side are approximately opposite to those on the other side.

Staggered intermittent fillet weld

Is defined as an intermittent fillet weld on both sides of a joint in which the weld increments on

one side are alternated with respect to those on the other side (see Figure 10).

Boxing (commonly referred to as end returning),

Is defined as the continuation of a fillet weld around a corner of a member as an extension of

the principal weld (see Figure 11).


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Figure 9 Welding Sequence

Figure 10 Intermittent Fillet Welds Figure 11 Boxing


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Part of the Weld Joint

Figure 12 Groove Weld


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Figure 13 Fillet Weld


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Part of the Completed Welds

Weld faceIs the exposed surface of a weld on the side from which welding was done.

Weld toeIs referred to the junction of the weld face and the base metal.

Weld root

Which is defined as the points, shown in cross section, at which the root surface intersects thebase metal surfaces.

The root surfaceIs the exposed surface of the weld opposite the side from which welding was done. Therefore,

the root surface is bounded by the weld root on either side.

Weld reinforcement

The weld metal in excess of the quantity required to fill a joint. The face reinforcement (alsocommonly called weld crown) is weld reinforcement on the side of the joint from which

welding was done.

The root reinforcement

Is weld reinforcement opposite the side from which welding was done. In both cases, thisrepresents that portion of the weld metal that extends beyond the surface of the base metal (see

Figure 14).

Figure 14 Parts of a Weld


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Weld toe

The junctions of the weld face with the base metal.

Fillet weld leg

Is the distance from the weld toe to the joint root.

Figure 15 Parts of a Weld

3.welding term

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