Characterisation of Grains by Barkhausen Noise and Eddy Current Testing

摘要

Controlling of some industrial components require the development of new andparticular non destructive testing techniques.To characterise a steel, it would benecessary to know its chemical composition, physico-chemical constitution,metallurgical state (annealed, hammered) and other parameters (superficial andchemical processing, ...). The microstructure of metallic alloy depend on thechemical composition, elaboration processing, and thermal processing.The testing method using Barkhausen noise (B.N.) is a particular method ,which canbe applied on ferromagnetic materials .It is a magnetic non destructive evaluation(NDE) method and can provide very important information about the materialstructure .The eddy current methods can also be appliedThe aim of our work is to study the material structure using these techniques ,tocharacterize the region submitted to thermal processing .Sample of steel have beenheated at the temperature d 1100 癈 with variable maintain time. These methodspermits to see the influence of the degree of cold deformation on grainsize ,microstructure types ,microstructural changes, hardness changes after thermaltreatment.