Barkhausen noise analysis in practice: Hardness detection

Barkhausen noise analysis gives a response to the hardness state.

Hardness is related to the number of pinning sites (dislocations, precipitations, or other irregularities) in a material. When a magnetic field is applied to a ferromagnetic material, magnetic domain walls start to move. Domain walls collide with pinning sites in the material structure which impedes the domain wall movement.

In soft materials magnetic domain walls move more easily than in hard materials. This is because in hard materials there are lots of pinning sites and therefore domain wall movements are more restricted. In soft materials domain walls can make bigger jumps.

Barkhausen noise signal is caused by the jumps of the domain walls between the pinning sites. In practice, the softer the material, the higher the Barkhausen noise signal amplitude due to the less restricted movement of domain walls, and vice versa for the hard materials.

High hardness leads to low Barkhausen noise activity and low hardness to high Barkhausen noise activity. Barkhausen noise analysis can be easily used to separate soft and hard parts in heat treatment applications, and for detecting grinding burns.


We provide Barkhausen noise inspection systems for a wide range of steel components in following automation levels:

RoboScan

Inline/Robot Systems

RoboScan is an automated grinding burn and heat treatment defect detection system that can be integrated into production line.

GearScan 500 and user

Automated systems

Automated systems for quality inspection are tailored for offline use. Easy to use software makes inspections intuitive and systems can adapt to various component types.

CrankScan 200 with user

Semi-Automated systems

Semi-automated and manual Barkhausen noise analysis systems are suitable for low volume measurements. The most simple Barkhausen noise measurements can be performed handheld with only a sensor and analyzer.

Barkhausen noise analysis with Rollscan 350 and general purpose sensor.

Manual systems

Manual Barkhausen noise stands are grinding burn and heat treatment defect detection systems for low-volume applications.