Barkhausen noise emission in tool steel X210Cr12 after semi-solid processing

Highlights: • Barkhausen noise is sensitive to the microstructure alterations of tool steel. • Barkhausen noise exhibits good correlation against hardness. • secondary carbides give rise higher interaction with BW's than primary carbides. -- Abstract: This study reports about magnetic Barkhausen noise in tool steel X210Cr12 after semi-solid forging. Semi-solid subsequent forging involves the partial melting of the workpiece followed by quenching. This process remarkably affects the character of the resulting matrix; stress state; volume of retained austenite; and the size, morphology and distribution of carbides. However, severe non-homogeneity can be found across the sample due to exerted load concentration in the centre of the sample. Non-destructive Barkhausen noise signals and extracted parameters are correlated with conventional destructive analyses performed by metallographic and scanning electron microscopy observations, microhardness and X-ray diffraction measurements. Due to matrix refinement, the volume of retained austenite was altered, carbides were fragmented, Barkhausen noise remarkably decreased and the Barkhausen noise envelope exhibited two peaks. The conventional effective value of Barkhausen noise strongly correlates with hardness. Therefore, Barkhausen noise could be applied for monitoring of tool steel X210Cr12 after semi-solid forging as the technique capable to distinguishing the variable character of the microstructure (expressed in the complexity of this term) and stress state in.