Arc Blow Caused by Self-Magnetic Fields
Arc self-induced magnetic blow is the alteration of the plasma flow due to the uneven build-up of the magnetic field around the arc, especially at high DC currents or poor current pick-up. This leads to uncontrolled penetration patterns and can cause damage to the workpiece or the welding equipment.
Physical-Chemical Mechanism of Action
Arc blow occurs when the plasma in the arc is deflected by an uneven magnetic field. With high direct currents or poor current return paths, an asymmetric magnetic field forms, which deflects the plasma and changes its movement.
Metallurgical Relevance & Welding Risks
This deflection leads to uncontrolled penetration patterns, which affects weld quality. It can cause uneven workpiece deformation or even damage to the welding equipment. Additionally, the risk of cracks and failures in the weld area increases.
Workshop Practice & Instructions
To minimize arc blow, take the following measures:
• Use a homogeneous current path and optimize the current return.
• Make sure the arc is properly aligned and the plasma is not deflected.
• Check the welding equipment regularly and perform maintenance as needed.