  A recently presented model is adapted to predict the effects of strain path
change on the strain aging (bake hardening) behaviour of an ultra low carbon
(ULC) steel. Samples pre-deformed by rolling were aged and then tested in
uniaxial tension at 0, 45 and 90$^\circ$ degrees to the prior rolling
direction. The results show that aging changes not only the yield strength of
the material but also the work hardening rate. The increase in yield strength
is interpreted to be dominated by a reduction in mobile dislocation density,
this reflecting the classic ideas of Hahn and others. The change in work
hardening behaviour is treated as arising from the different role played by
solute `loaded' dislocations compared to dislocations generated by straining
after aging.
