The e!ect of microstructural change during isothermal heat treatment on structure
-sensitive magnetic properties has
been investigated for 1Cr}1Mo}0.25V steel. Magnetic permeability increased, but
coercive force and Vickers hardness
decreased as ageing time increased. During the isothermal heat treatment, Mn
23
C
6
and (Cr
2.5
Fe
4.3
Mo
0.1
)C
3
carbides
were found at grain boundaries. These
