Ferromagnetic workpiece magnetic and mechanical testing method

The workpiece (1) under investigation is periodically magnetised by electromagnet (3) driven by power supply (4) and function generator (5). A Hall sensor and pickup coil (2) are placed on the workpiece. Mechanical vibrations are induced in the workpiece by the striker of impulse generator (6) driven by function generator (8) and amplifier (7).The workpiece is driven by magnetic excitation frequency of 0.01 to 20 Hz, and by a mechanical frequency more than ten times this. These sound waves interact with magnetostrictive effects. The received signals are amplified (9-11) and analysed in narrow band measurement, then plotted against magnetic field strength on an X-Y plotter (14).