Magnetic nondestructive evaluation of thermally degraded 2.25Cr-1Mo steel

Aging was performed to understand the microstructural degradation in 2.25Cr-1Mo steel. Microstructural parameters (mean equivalent carbide size, number of carbides per unit area), mechanical properties (UTS, Vickers hardness) and magnetic properties (coercivity, remanence) were measured to investigate the relationship among these parameters. The magnetic coercivity and remanence were observed to decrease rapidly in the initial 1000 h of aging time and then decrease slowly thereafter. Linear correlations between mechanical and magnetic properties were found. (C) 2003 Elsevier Science B.V. All rights reserved.