Abstract: Annealing separator for heat treatment of a silicon steel sheet comprising not more than 0.2% SO.sub.3, not more than 0.04% Cl with the balance being MgO and unavoidable impurities, and having a bulk density between 0.18 and 0.30 g/cm.sup.3, and a particle size distribution of 40 to 70% of particles not larger than 3.mu.m, 10 to 25% of particles not smaller than 10.mu.m, not more than 15% of coarse particles larger than 15.mu.m with the balance being intermediate particles between 3.mu.m and 10.mu.m.

Abstract: Insulative coatings for electrical steels and methods of making them. The coatings are hard, glassy and smooth in nature, are easily cured and improve the magnetic characteristics of the electrical steels. The coatings are produced by applying to an electrical steel an aluminum-magnesium-phosphate solution containing Al.sup.+.sup.+.sup.+, Mg.sup.+.sup.+ and H.sub.2 PO.sub.4 .sup.- in a specified relative relationship and from 0 to 60% by weight colloidal silica on a water-free basis. The solutions contain at least 45% by weight water. Chromic anhydride (CrO.sub.3) may be added to the coating solutions to improve wettability of the solutions, moisture resistance of the resulting coatings and interlaminar resistivity after stress relief anneal. An electrical steel coated with a solution of the present invention is thereafter subjected to a heat treatment to cure the insulative coating thereon.

Abstract: Coatings for silicon steel comprised of MgO, an amorphous magnesia-silica complex and a boron bearing compound.

Abstract: Coatings for silicon steel comprised of MgO, an amorphous magnesia-silica complex and a lithium bearing compound.

Abstract: Novel amorphous magnesia-silica complexes containing from about 0.001 to 2.0 percent by weight of an alkali metal oxide, wherein the mole ratio of MgO:SiO.sub.2 of said complexes is from about 1:25 to 14:1.

Abstract: Method for producing a grain-oriented electrical steel sheet or strip having uniform magnetic and film properties said method comprising applying an annealing separator containing one or more metal nitrides, such as, chromium nitride, titanium nitride and vanadium nitride to the steel sheet and annealing the steel sheet at a temperature not lower than 1,100.degree.C.

Abstract: Insulative coatings for electrical steels having improved resistance to deterioration during stress relief anneals or other heat treatments carried on in reducing atmospheres. They may be produced by coating electrical steel with an aqueous solution of phosphoric acid, magnesium oxide and one or more additional mineral acids present in an amount sufficient to adjust the pH level of the solution to from about 0.5 to about 3.0. The mole ratio Mg/PO.sub.4 should be from about 0.6 to about 1.5.

Abstract: A cold rolling method for producing a high magnetic flux density grain oriented electrical steel sheet or strip having remarkably excellent B.sub.8 characteristics, comprising subjecting a hot rolled steel sheet or strip a combination of heavy cold rolling with annealing during which the steel sheet or strip is held at a temperature between 100.degree. and 350.degree.C at an interim sheet thickness stage during the heavy cold rolling.

Abstract: Novel amorphous magnesia-silica complexes containing from about 0.001 to 2.0 percent by weight of an alkali metal oxide, wherein the mole ratio of MgO:SiO.sub.2 of said complexes is from about 1:25 to 14:1.

Abstract: Coatings for silicon steel comprised of MgO, an amorphous magnesia-silica complex and a lithium bearing compound.

Abstract: A process is described in which an iron-silicon alloy capable of being heat treated to produce a cube-on-edge (110) [001] grain orientation is treated to produce improved core losses when the material is under high operating inductions. The process steps include cleaning the surface of the steel of finish gauge thickness, applying a coating to the surface of the steel which is non-reactive with the surface and promotes decarburization, heating to a temperature sufficiently high to effect secondary recrystallization texture development and decarburization and cooling to room temperature. Data are included which demonstrate the improved core losses exhibited by these materials so treated when tested at high operating inductions.

Abstract: A highly adhesive and uniform insulating glass film can be formed on surfaces of an oriented silicon steel sheet by pickling a finally cold rolled silicon steel strip just before a decarburizing annealing, and successively subjecting the pickled steel strip to the decarburizing annealing, an application of an annealing separator and a final annealing at a high temperature.

Abstract: A method for producing a grain-oriented electrical steel sheet showing super low watt loss, comprising making a silicon steel ingot containing 2.5 to 4.0% of Si, subjecting the ingot treatments including hot rolling, annealing and at least one cold rolling to obtain a final size, subjecting the steel to decarburization annealing and a finishing annealing which completes secondary recrystallization, subjecting the steel to remove surface product and then subjecting the steel to chemical polishing or electrolytic polishing to polish the steel surface to mirror condition.

Abstract: Magnesium oxide coating compositions, process for their preparation and process for applying said compositions as adherent dried coatings which when annealed form relatively non-porous insulations providing improved electrical insulating properties. The coating compositions comprise a major proportion of magnesium oxide and a minor proportion of zinc permanganate and magnesium sulfate, wherein the concentration of zinc permanganate is from about 4 to about 16 parts per 100 parts of magnesium oxide and the concentration of magnesium sulfate is at least about 50 parts per 100 parts of zinc permanganate.

Abstract: An insulating glass film having an excellent uniformity and a high adhesion to a grain-oriented silicon steel sheet having a high magnetic induction is formed by annealing a coil of a cold rolled silicon steel sheet having a final gauge in an annealing furnace under a non-oxidizing and non-reducing neutral inert gas, such as nitrogen or argon at a constant temperature keeping stage of 800.degree.-920.degree.C and then under dry hydrogen at a temperature of 1,000.degree.-1,200.degree.C in the final annealing stage.

Abstract: An object of silicon steel, such as sheet and strip for motors, generators and transformers, which has an insulating coating of silicate, is provided with a solution of phosphate by applying to the silicate-coated object an aqueous solution containing phosphate ions and complex metal-ammonia ions and heating the coated object to a temperature of at least about 550.degree.C for a time sufficient to anchor the resulting phosphate layer to the silicate coating. The solution has a pH-value of at least 9, and consists essentially of monophosphate ions. The metal ions are cupric ions and/or chromic ions. An insoluble filler may be added to the aqueous solution.

Abstract: A steel object, such as sheet and strip for motors, is provided with a heat-resistant, electrically insulating coating in the form of a layer of calcium titanate. An intermediate layer of silicate may be provided between the steel surface of the object and the layer of titanate. The intermediate layer is preferably a silicate of one or more alkaline earth metals or of aluminum, and especially a silicate of magnesium.The coating of calcium titanate may also contain a vanadium compound. Likewise, a layer of phosphate may be provided on the outside of the layer of titanate.