Contactless magnetic powder testing of hollow ferromagnetic cylinders - using coil to generate field in pipe end region and detecting resulting magnetic powder alignment

摘要

Magnetic power testing of interior end regions of ferromagnetic hollow cylindrical workpieces involves generating a magnetic field inside the workpiece using a coil and detecting defect locations from the resulting orientation of magnetic powder applied to the workpiece surface. An air coil with longitudinal sides parallel to the workpiece axis is inserted into the workpiece and moved out of ite as the workpiece and coil rotate w.r.t. each other. The field lines (10,11) circulating through the coil terminate at the workpiece wall (1). -