Barkhausen Noise as a Magnetic Nondestructive Testing Technique
AbstractThere are many destructive and non-destructive tests for detecting microstructural changes and faults in steel parts. The term “non-destructive testing” (NDT) is used for material testing methods that can be applied without harming the material. NTD can be applied to materials, parts, assemblies or structures. One of the non-destructive evaluation methods is Barkhausen Noise (BN) that is magnetic based and is used mainly in the automotive and aviation industry. Barkhausen noise (BN) measurement is an electromagnetic testing method that is suitable for ferromagnetic materials. Ferromagnetic materials are made up of small magnetic domains which are separated by domain walls and orientated in different direction. As a result of the external magnetic field applied, domains will turn to the direction of magnetization, moving the domain walls which will cause jumps of magnetic flux denstiy. These jumps are called Magnetic Barkhausen Noise (MBN). MBN is sensitive to different material properties such as microstructure, composition, residual stress and hardness. This paper focus on describing an improved Non-Destructive Testing methology based on the analysis of BN. It also explaines the relationship between material properties and BN profile. Also, it is aimed to introduce applications and test equipments of BN.