Inductance - more confusion

[jim.bloor@xxxxxxxxxxxxxxxxxxxx]

Hi

Thanks to everone who responded to my plea for info on calculating 
inductance. However, I've now received some conflicting 
information. I understand that to determine inductance requires 
selecting an area of the model and obtaining the energy by 
integrating but one source says "integrate over the whole model" 
which I take to mean everything right out to the boundary, whilst the 
other source says "integrate only over the copper winding area". 
Which is correct? 

My feeling is that integrating over the whole model is the right way 
because the energy originates only from the coil. The magnetic flux 
generated would interact with the whole of the model and thus affect 
the inductance.

Has anyone found a good source of magnetic data for stainless steels 
(other than MatLab)?

Regards
Jim Bloor