B/H curve relationship

Thread Starter


Joined Jul 13, 2020
i have been on this question all day reading and searching on line but i am not sure how to answer it. every article on the relationship of B/H immediately goes into equations and does not explain anything .

all i can think to say is that with cast iron the flux density increases fast to 0.5 at a field strength of 2000 at/m the flux density then gradually increases at a slower rate to a maximum of 0.9 at the field strength goe from 20 at/m to 8000at/m .

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



Joined Dec 29, 2008
... It seems like you can consider the abscissa as a sort of cost or expense, and the ordinate as the product or goal to be achieved, for a given material.


Joined Feb 24, 2006
What the curve is telling you is that cast iron is a material that does not allow a higher field strength for increases in flux density past about 2000 At/m. Mild Steel on the other hand gets to 87.5% of its asymptotic limit for only 2000 At/m. For the same mechanical dimensions you get more bang for the buck. This effect is called saturation, where more flux doesn't make a stronger field. This is also quadrant I of the 4 quadrant hysteresis curve.