Nondestructive characterization of 2Cr-1Mo steel quality using magnetoacoustic emission

This paper describes experiments with 2Cr-1Mo-grade steel at various stages of creep damage. Properties of magnetoacoustic emission (MAE) were tested and compared to other magnetic properties such as hysteresis loop B(H), Barkhausen effect (HBN), and magnetostriction /spl lambda/. The creep-damage stage was evaluated from microstructural analysis and mechanical properties tests. It was revealed that incipient creep damage leads to decrease of MAE and magnetostriction as well to slight decrease of coercivity Hc and to nonmonotonic behavior of HBN intensity. These features are discussed qualitatively using models of magnetic hysteresis and of MAE.