Course question help B/H curve

[apache]

Q - Using the above graph, comment on how the material affects the B-H relationship for cast iron and mild steel



I have no idea what is required here its online course and do not get help.

Do they want me to describe what is happening for example

Cast iron , flux density B increases quite quickly until a field strength of 2000 at/m when the flux density increase start to slow gradually climbing to a maximum if 0.9T from 2000 at/m to 8000 at/m

its supposed to be 300 words but ???

 

[telectrix]

something like ------ the graphs show the relationship between flux density and mag.field strength for different materials . relevant to this question, specifically mild steel and cast iron. where the graphs level out,saturation is reached and increase of mag. fiels further does not increase the flux density. it can be seen from the graphs that the 2 materials react differently. wheaeas mild steel has a much more dramatic increase in flux density, it satureates at a lower level of mag. field .... etc.,etc. that's only 60 ish words, but try and expand on it.

 

[apache]

ok , thanks .

 

[Lucien Nunes]

The gradient of the curve in its linear ferromagnetic region before saturation gives the permeability of the material. Mild steel exhibits higher permeability hence its steeper curve. Both materials enter saturation at around 2000At/m, but the saturation transition or 'knee' in the curve is more abrupt for mild steel. Thereafter the gradient reduces towards the paramagnetic value of permeability.

You could explain the mechanism of ferromagnetism and how the domains in the material progressively align with the applied field. Then you could indicate the effect it has on the practical uses of the material in electrical machines, e.g. that the higher permeability of steel allows a higher flux density (which is usually desirable) for a given field strength enabling machines to be made smaller and lighter than with cast-iron.

You'll easily overflow 300 words.