Undercut
There are two basic reasons why an undercut forms, though it can happen for other causes as well. The first involves employing too much current, which causes the joint’s edges to melt and leak into the weld. The second reason is that the weld does not have enough filler metal placed in it. As a result, the cross-section is reduced, resulting in notches or grooves along the weld that enhance stress when fatigue loading is applied to the material. This flaw appears at the weld’s toe or, in the event of many runs of welding, at the fusion face. Inter-run, intermediate, and continuous runs can all result in an undercut.
Furthermore, dirt and water have a tendency to get trapped in the groove, which can hasten corrosion in the area that is already weak.
Causes of Undercut
- High arc length.
- Incorrect electrode selection.
- Wrong angle.
Preventions of Undercut
- Smaller arc length.
- Small voltage.
- Small travel speed.
- Reducing the electrode diameter.
Defects in Welding
A perfect weld is essentially unachievable in practice, and most of the time it is not necessary to give the requisite level of service functions. As a result, in order to define what is appropriate and suitable for use, numerous industries have set standards and tolerances for welds. These allow for different kinds, sizes, and frequencies of flaws and are described as codes or standards.
The identical weld may be permitted under one code but not under another because some rules are more stringent than others. Weld surface irregularities, discontinuities, flaws, or inconsistencies that appear in welded objects are referred to as welding defects. Weld joint flaws may cause assemblies and parts to be rejected, expensive repairs to be made, a major decrease in performance under working conditions, and, in the worst situations, catastrophic breakdowns that cause property and human casualties.
These flaws have multiple root causes. The majority of the time, poor weld design, inappropriate welding techniques, and the use of incompatible materials lead to flaws. These flaws can also be caused by inadequate welder training, shoddy workmanship, and a lack of process expertise. Furthermore, because of the inherent weaknesses in welding technology and the properties of metals, there are always certain faults in the welding.
Table of Content
- Welding Defects
- External Welding Defects
- Internal Welding Defects
- How to Detect Welding Defects
- Conclusion
- FAQs