Torsional Fatigue Behavior of 8620 Steel Subjected to High Magnetic Field Thermal Processing

The potential for improving behavioral properties of common materials via thermal processing within a high magnetic field has been the subject of numerous recent works.  In this study, torsional fatigue performance of case-carburized SAE 8620 re-austenitized and quenched inside of a 9 Tesla superconducting magnet was examined.   As-hardened and tempered, and in-situ magnetic field re-hardened and tempered steel was subjected to fully-reversed torsional loading, generating comparative S-N curves for forged and for as-rolled bar conditions.  Although an obvious separation was observed between the baseline samples (as expected, forged parts were better), there was no measurable difference in either condition between the conventionally carburized and magnetic field re-hardened populations.