Metalworking and magnetization

[theorem]

I heard/read somewhere some time ago during my electromagnetism course that when rolling a piece of metal into a metal plate, the magnetization properties will vary depending on how you apply the outer magnetic field. For instance if you apply a magnetic field perpendicular to the "direction" the plate had been rolled in, the magnetization will be less than if the magnetic field would be applied in the same direction as it was rolled in.
Question: How does rolling a piece of metal into a metal plate affect its magnetic properties?

I also heard that it is common to add some concentration of silicon to the metal mixture in order to increase the effect even further.
Question: If this is true: how does silicon alter the magnetization properties?

 

[zoki85]

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