Re: Altering steel in a magnetic field.

Hi Bud,

The physical properties of steel do not change after exposure to strong AC 
magnetic fields.  The force exerted on the steel by the magnetic field is 
not normally strong enough to cause permanent changes in crystaline 
structure, which would produce changes in physical properties.  Heating 
of the steel does occur, and induction heating is a commonly used method 
for melting steel.  

An AC field is used to demagnetize steel before attempting to measure the 
permeability.  This is done to remove the magnetization caused by the 
Earth's magnetic field.  The permeability measurement will not be accurate, 
if it is measured without first demagnetizing the steel.

Bob Novak
Specialist - Process R&D
Carpenter Technology