FFI OFP4p Non-destuctive characterization concepts for production

Important results from the project

12 partners från universitet, forskningsinstitut, bilindustrin och stålindustrin samarbetade för att realisera de övergripande målet: kombination av Barkhausen Noise Testing (BNT) och Ultraljudstestmetoden (UT) för mätning av hårdhet (eng. Case Hardening Depth - CHD). Det visades att BNT funkar upp till 1 mm djup och UT från 5 mm och djupare. Mellanrummet bör täckas antingen av nya BNT-sensorer eller annan oförstörande provningsmetod (OFP). Det visade sig att CHD kan användas för induktionshärdade och nitrerade komponenter genom en kombination av BNT och UT.

Expected long term effects

The main outcomes from the project are as follow: the developed test matrix showed a strong correlation the hardness depth for BNT and UT; the BNT is more sensitive to the microstructure changes; UT showed a clear correlation to the hardening depth at depths more than 5 mm; the rougher surface increase BNT signal values; the increase of grinding feed-rate increase BNT signal; the step to create calibration block set for BN equipment has been made; the good practice guide book for BNT contains the knowledge for establish custom methods in industrial applications.

Approach and implementation

Work was divided in workpackages. The developed MVVS parameter can be implemented directly as a new descriptor of Case Hardening Depth. However, there are still many factors to investigate before full industrial implementation. Therefore, the future research should be conduct in areas of microstructure effect on BNT, active control of the machining processes, calibration methodology, machining optimization methods, and application of non-destructive methods for additive manufacturing. These can lead towards standardization on Barkhausen method.