Magnetic Arc Blow
Magnetic arc blow is the deflection of the welding arc by non-uniform magnetic fields. It causes weld defects and spatter and requires adjusting the position of the work clamp.
Physicochemical Mechanism of Action
The welding arc is ignited by electrical voltage between electrode and workpiece. In uneven magnetic fields, the electrons in the arc are not attracted uniformly, causing the arc to deflect.
Metallurgical Relevance & Risks in Welding
The deflection can lead to inaccurate weld positions and spatter in the weld. This compromises the quality and mechanical properties of the overall weld joint, increases the risk of cracks, and reduces component service life.
Shop Practice & Action Instructions
To minimize magnetic arc blow, adjust the position of the ground clamp so that the welding arc is as perpendicular to the weld direction as possible. This can be achieved by carefully positioning the electrode and the workpiece. In strong magnetic fields, it is advisable to run the weld in the direction of the magnetic field or to neutralize the field.