Coercive Force Of Ferromagnetic Material Testing Technology Research

With the rapid development of modern industry, the ferromagnetic material is morewidely used in various fields of industry, and therefore safe operating condition detectingferromagnetic material is necessary, detection of ferromagnetic material is divided into twomajor destructive testing and non-destructive testing class, as non-destructive testing willnot bring damage to the material, the stress detection using multi-stage approachferromagnetic NDT, NDT method of ultrasonic photoelastic method, X-ray method,Barkhausen effect of stress detection methods, stress detection method based on the inversemagnetostrictive effect is widely used.In this paper, a ring of ferromagnetic material measured object, using electromagneticdetection principle, to study the relationship between the coercivity and the stress offerromagnetic material is proposed to detect the use of coercive force of ferromagneticmaterial suffered achieve detection The method stresses. Measurement of ferromagnetichysteresis loop ring calculated coercivity, experiments ferromagnetic ring in a symmetricalposition on the same number of turns of winding excitation coil and magnetic detectioncoil material parameters based on the hysteresis loop in the detection alternating currentthrough the coil to a frequency amplitude, the output of the excitation coil is an access tothe sampling resistor, the magnetic field strength H can be obtained proportional to the sizeof the signal at the output of a detection coil of the access points that can be obtainedmagnetic induction B signal proportional to the size of the excitation coil and a detectioncoil are connected to the output of the XY side of the oscilloscope, the oscilloscope toobserve BH curve, the curve and the horizontal axis is the size of the intersection ofcoercivity. Experiments were measured discontinuity with ferromagnetic hysteresis loopring, between the value of its coercivity coercivity ferromagnetic materials research andmaterials the stress relationships; applied in the measurement process an external magneticfield, observe the effect of the magnetic field caused by the measurement results; let themeasured mechanical vibrations ferromagnetic rings do observe the change of the hysteresis loop before and after vibration; magnetic excitation signal amplitudes weremeasured in different ferromagnetic ring hysteresis loops, of hysteresis loop shape, observethe effect of magnetization on the measurement results caused. Experimental results showthat, when the ferromagnetic material subject to stress, the material shape of the hysteresisloop will change;coercive force of the ferromagnetic material and the material isproportional to the stress; coercivity material and material of the mechanical movementindependent;magnetic properties of ferromagnetic material only when the measuredparameter reaches a saturation hysteresis loop of magnetic material in order to reflect, andthen increase the magnetic field strength at this time does not cause a material change ofthe coercive force.