Further reading

What is Barkhausen noise?

Barkhausen is based on inductive measurements of a noise-like electromagnetic signal that is generated in a ferromagnetic material caused by an external magnetic field.

Properties of Barkhausen.

Barkhausen gives information about changes of residual stresses and microstructure in the surface of a component made by ferromagnetic steel..

Detection methods of grinding damages.

Barkhausen can be used to detect grinding burns and optimize your grinding process.

Grinding damages.

Thermomechanical damages after grinding, so called grinding burns, will shorten the fatigue life and can cause severe failures in dynamically loaded, critical components.

Grinding control of camshafts.

Barkhausen is an excellent method to control and optimize the grinding process of camshafts.

Rsidual stresses from grinding.

Grinding is a process which requires high energy to remove material. The high energy, in return, generates heat. The heat is absorbed by the workpiece and will cause heat treatment that will change the microstructure and residual stresses.

The importance of residual stresses.

Residual stresses are the internal stresses of a component, caused by treatments in the history of the component.

Residual stresses from machining.

Residual stresses are induced during the machining due to mechanical, thermal or chemical factors. They may lead to shorter fatigue life, hence they should be analyzed and controlled..

Distortion and residual stresses.

Distortion is the unexpected, uneven change in size or shape caused by dissimilarities in manufacturing and heat treatment processes. Distortion is affected by material properties, part geometry, the size of the component and the most importantly, the residual stress state of the component.

Different methods to influence the residual stresses.

Thermal and mechanical treatments are available to relieve the residual stresses.

Why measuring residual stresses?

Residual stress measurement is one essential way to find out if the component can withstand the demanding load and stress conditions in its service life.

Measurement methods for residual stresses.

There are many methods said to measure residual stresses. However, there is no direct method to measure stresses. They are calculated or derived from a measured quantity such as elastic strain or displacement.