Determination of metal surface hardened layer depth using magnetic barkhausen noise

Radiography, microhardness measurements, residual stress distribution curves, decoding of dislocations, metallographic methods, method of different etching rate of the stressed and not stressed areas of crystal, and others are used at present for determination of metals plastic deformation locality. All these methods are long-term, labour consuming and rather inaccurate. The purpose of the work was to develop reliable and rapid non-destructive durable method of hardened layer depth measuring using magnetic Barkhausen noise. The tests showed that using this method it is possible to determine the depth of hardened surface layer at accuracy of 0.01 mm.