Welding Strength Test
Even if you perform the welding in accordance with the conditions, the strength of the welded sections may fluctuate widely with drops in the voltage and other factors. The quality of the welding cannot be evaluated unless the welded sections are destroyed.
Provide yourself with a steel plate of the same thickness and conduct a destruction test.
- If holes appear in the steel plates (1, 4), this means that the welding is standard strength.
- Drive a wedge (2) between 2 panels near the nugget. If the welded parts do not come apart and the diameter of the nugget (3) appears more than 3 mm, the welding should be satisfactory.
IMPORTANT:
It is difficult to perform spot welding in the following circumstances.
- When it is not possible to remove any rust or paint attached to the welding surfaces.
- When the tip of the spot welder cannot be inserted into the welding section.
- When the welding surfaces can be seen from the outside and welding will impair the exterior appearance.
In all these cases, it is recommended that the gas welding method be employed. However, if it is not possible to perform spot welding because of space restrictions, plug welding based on the arc welding method may be performed instead. Here the welding sections must be close together.