Effects of heating rate and surface oxidation on magnetic induction of 3% Si-Fe strip

The effects of heating rate and surface oxidation on magnetic induction of thin-gauged 3% Si-Fe strips have been investigated. Magnetic induction incr eased with increasing final annealing temperature. Before and after 1150 de grees C, the planar orientation of grains shifted from (100)[011] to (110)[ 001], resulting in magnetic induction higher than 1.90 T. Magnetic inductio n after final annealing was higher in case of a faster heating rate. This i s because enough time for growth of (110) grains is given in the case. Irre spective of transient annealing temperature, magnetic induction after final annealing was mostly higher than 1.90 T. A maximum, 1.97 T, was obtained a t a transient annealing temperature of 800 degrees C. This is because iron oxide formed at 800 degrees C inhibited the surface-energy-induced selectiv e growth of (100)[011] grains during heating up to 1200 degrees C. (C) 2000 American Institute of Physics. [S0021-8979(00)27708-6].