Certified Welding Inspector Practice Exam

What causes arc blow during the welding process?

1. Excessive heat at the electrode tip

2. Movement of the workpiece

3. Magnetic forces deflecting the welding arc

4. Inconsistent current supply

The correct answer is: Magnetic forces deflecting the welding arc

Arc blow is a phenomenon that occurs during the welding process, primarily due to the influence of magnetic fields on the welding arc. When the welding current flows through the workpieces, it generates a magnetic field. If there are ferromagnetic materials nearby or if the workpiece itself has a significant magnetic property, this can lead to magnetic forces that deflect the welding arc from its intended path, causing instability in arc performance. The presence of these magnetic fields can arise from factors such as the configuration of the workpieces, the position of the welding lead, and the proximity of other magnetic materials. When the arc is deflected, it can lead to difficulties in achieving a consistent weld quality, resulting in issues such as poor fusion or excessive spatter. Understanding this phenomenon is crucial for welders and welding inspectors, as it directly relates to the quality of the completed weld and the efficiency of the welding process. Proper setup and consideration of the magnetic effects are important for minimizing the occurrence of arc blow during welding operations.