Weld bead and its properties

Weld bead and its properties

Weld beads have a greater impact on the quality of a sound weld joint. In this article, we discussed the basic structure of a weld bead.

Weld bead geometry

In terms of the properties of a weld joint, weld bead geometry has considerable parameters that can alter the mechanical properties of a welded joint. These properties are affected by certain welding parameters like

• Arc current,
• Arc voltage, and
• Arc travel speed, etc.

Specification of a weld bead

Bead geometry can be defined on the basis of the following points ...

• Weld bead width,
• Reinforcement height,
• Reinforcement area,
• Penetration height,
• Penetration area, and
• Contact angle of the weld bead.

Many other factors like nugget area, percent dilution, pool shape factor, bead shape factor, and ripple shape factor may also be included in the bead geometry.
Aspects of weld bead geometry

Width of the weld bead

The maximum width of the deposited metal is considered the width of the weld bead. It increases with arc current, arc voltage, and electrode weaving and decreases as arc travel speed increases.

Penetration

The efficiency of load-carrying capacity is determined by the penetration of a welded structure.

Penetration height

The height of penetration is actually the distance from the plate top surface to the maximum extent of the weld nugget.

Penetration area 

The Penetration area is covered by the fusion line below the base metal level. It is responsible for the affection of the weld strength.

Reinforcement height

 The maximum distance between the base metal level and the top point of the deposited metal is called reinforcement height.

Reinforcement Area

Reinforcement area is one included between the contour line of the deposited metal above the base metal level

Contact angle

The contact angle is included between the tangent to the weld metal at the point weld metal and base metal meet and the base metal line. It influences bead shape undercuts and overlapping.

Penetration height, penetration area reinforcement height, and reinforcement area, all increase the arc current increase and as arc travel speed decreases.

Conclusion

Thus thinner workpieces require lesser currents, small diameter electrodes, and faster arc travel speed as compared to thicker jobs,
Penetration can also be increased or decreased by deflecting the welding arcs in the backward or forward direction, using DC magnetic fields.
forward direction, using DC magnetic fields.