Magnetic Yoke Magnetization
A magnetization method in magnetic particle testing utilizing a manageable electromagnet yoke to generate a local magnetic field between poles within the component. It is flexibly applicable for mobile weld inspection.
An electromagnetic yoke creates a magnetic field between its poles. You apply the magnetic powder to the surface, and it collects where leakage fields emerge – at cracks or other defects. You see that as an accumulation. For weld inspection, this means: you must position the yoke so that the field is perpendicular to the expected crack direction, otherwise you'll miss the defects. Make sure the pole feet sit cleanly and the powder is applied thinly and evenly. Too much powder or too weak a field smears the image – then the indication becomes unclear.