Silicon steel and processing therefore

Claim 1

In a process for producing electromagnetic silicon steel having a cube-on-edge orientation, which process includes the steps of: preparing a melt of silicon steel containing from 0.02 to 0.06% carbon, from 0.0006 to 0.0080% boron, up to 0.0100% nitrogen, no more than 0.008% aluminum and from 2.5 to 4.0% silicon; casting said steel; hot rolling said steel; cold rolling said steel; decarburizing said steel; applying a refractory oxide coating to said steel; and final texture annealing said steel; the improvement comprising the steps of coating the surface of said steel with a refractory oxide coating consisting essentially of: (a) 100 parts, by weight, of at least one substance from the group consisting of oxides, hydroxides, carbonates and boron compounds of magnesium, calcium, aluminum and titanium; (b) up to 100 parts, by weight of at least one other substance from the group consisting of boron and compounds thereof, said coating containing at least 0.1%, by weight, of boron; (c) from 0.5 to 50 parts, by weight, of manganese sulfate; (d) up to 50 parts, by weight, of oxides less stable than SiO 2 at temperatures up to 2150° F., said oxides being of elements other than boron; (e) up to 40 parts, by weight, of SiO 2 ; (f) up to 20 parts, by weight, of inhibiting substances; and (g) up to 10 parts, by weight, of fluxing agent; and final texture annealing said steel with said coating thereon; said steel having a permeability of at least 1870 (G/O e ) at 10 oersteds and a core loss of no more than 0.720 watts per pound at 17 kilogauss-60 Hz.