Patent classifications
C21D8/1205
Non-oriented electrical steel sheet and method for manufacturing the same
A non-oriented electrical steel sheet produced by hot rolling a steel slab containing, by mass %, C: not more than 0.0050, Si: 3.2 to 4.5%, Mn: 0.1 to 2.0%, P: not more than 0.020%, As: not more than 0.0030%, Sn+Sb: 0.005 to 0.10%, and one or two elements selected from Mo and W by a content ranging from 0.0020 to 0.10% in total, subjecting the resultant steel sheet to one cold rolling or two or more cold rollings including an intermediate annealing therebetween to achieve a final sheet thickness, and then subjecting the cold rolled sheet to finish annealing, a N.sub.2 content in an atmosphere in the finish annealing is set to not more than 20 vol %, and average strain rate in the first pass is set to not more than 4/sec, allowing the cold rolling property to improve with no degradation in magnetic property and no decrease in productivity.
Non-oriented electrical steel sheet and method for producing same
A non-oriented electrical steel sheet according to an exemplary embodiment of the present invention includes 2.0 to 4.0% of Si, 0.05 to 1.5% of Al, 0.05 to 2.5% of Mn, equal to or less than 0.005% of C (excluding 0%), equal to or less than 0.005% of N (excluding 0%), 0.001 to 0.1% of Sn, 0.001 to 0.1% of Sb, 0.001 to 0.1% of P, 0.001 to 0.01% of As, 0.0005 to 0.01% of Se, 0.0005 to 0.01% of Pb, 0.0005 to 0.01% of Bi, a remainder of Fe, and inevitable impurities, as wt %, wherein a Taylor factor (M) of each crystal grain included in a steel sheet is expressed in Formula 1, and an average Taylor factor value of the steel sheet is equal to or less than 2.75:
(here, σ is a macro stress, and τ.sub.CRSS is a critical resolved shear stress).
METHOD FOR PRODUCING GRAIN ORIENTED ELECTRICAL STEEL SHEET
A method for producing a grain oriented electrical steel sheet includes a decarburization annealing process where an oxidation degree PH.sub.2O/PH.sub.2 is controlled, a final annealing process where hydrogen in mixed gas atmosphere is controlled to 50 volume % or more, an annealing separator removing process where water-washing is conducted using solution with inhibitor, a smoothing process where chemical-polished is conducted to control average roughness Ra, and an insulation coating forming process where insulation coating forming solution in which crystalline phosphide is included is applied.
Method for manufacturing grain-oriented electrical steel sheet
In a grain-oriented electrical steel sheet which is manufactured from a thin slab without using an inhibitor forming component, excellent magnetic properties are stably achieved. In a method for manufacturing a grain-oriented electrical steel sheet, a slab heating and annealing are performed under specific conditions.
METHOD AND SYSTEM FOR PRODUCING LOW CARBON FERROALLOY FROM CHROMITE ORE
A method and system for recovering a high yield of low carbon ferroalloy, e.g., low carbon ferrochrome, from chromite and low carbon ferrochrome produced by the method. A stoichiometric mixture of feed materials including scrap aluminum granules, lime, silica sand, and chromite ore are provided into a plasma arc furnace. The scrap aluminum granules are produced from used aluminum beverage containers. The feed materials are heated, whereupon the aluminum in the aluminum granules produces an exothermic reaction reducing the chromium oxide and iron oxide in the chromite to produce molten low carbon ferrochrome with molten slag floating thereon. The molten low carbon ferrochrome is extracted, solidified and granulated into granules of low carbon ferrochrome. The molten slag is extracted, solidified and granulated into granules of slag.
METHOD OF MANUFACTURING NON-ORIENTED ELECTRICAL STEEL SHEET
To stably improve the magnetic flux density by utilizing induction heating and radiant heating during final annealing of a non-oriented electrical steel sheet. A method of manufacturing a non-oriented electrical steel sheet, including subjecting a slab having a predetermined chemical composition to hot rolling with or without performing hot-rolled sheet annealing, and then to cold rolling either once, or twice or more with intermediate annealing performed therebetween, and then to final annealing, where a material before final cold rolling has a recrystallization ratio of less than 80% and a {100}<011> intensity of 8 or less in a ¼ layer, and in the final annealing, an average heating rate from 600° C. to 720° C. is 50° C./s or higher, and an average heating rate from 720° C. to 760° C. is 5° C./s or higher.
GRAIN-ORIENTED ELECTRICAL STEEL SHEET WITH EXCELLENT MAGNETIC CHARACTERISTICS
Provided is a grain-oriented electrical steel sheet, the core loss characteristics of which have been significantly improved without causing a deterioration in magnetic flux density. The grain-oriented electrical steel sheet: comprises 2.5-3.5% by mass of Si with the balance being Fe and inevitable impurities; has a sheet thickness of 0.18-0.35 mm; has a metallographic structure including matrix grains of Goss-oriented secondary recrystallized grains after secondary-recrystallized annealing, wherein Goss-oriented crystal grains existing in the matrix and having a major (long) diameter of 5 mm or smaller exist in the metallographic structure at a frequency of 1.5 grains/cm.sup.2 to 8 grains/cm.sup.2; and has a magnetic flux density B8 of 1.88T or greater. As for the orientations of the Goss-oriented crystal grains having a major (long) diameter of 5 mm or smaller, the <100> orientation of the Goss-oriented crystal grains deviate from the rolling direction by an angle of 7 degrees or smaller and by an angle of 5 degrees or smaller in terms of a simple average of an α angle and that of a ß angle, respectively.
α angle; the angle formed by the longitudinal direction and the projection of the [001] on specimen surface, and
ß angle; the tilt of the [001] out of the specimen surface
NON-ORIENTED ELECTRICAL STEEL SHEET
This non-oriented electrical steel sheet includes a base metal having a predetermined chemical composition satisfying the expression [Si+0.5×Mn≥4.3], and an average grain size of the base metal is more than 40 μm and 120 μm or less.
METHOD AND SYSTEM FOR PRODUCING LOW CARBON FERROCHROME FROM CHROMITE ORE AND LOW CARBON FERROCHROME PRODUCED THEREBY
A method and system for recovering a high yield of low carbon ferrochrome metal from chromite ore and low carbon ferrochrome metal produced by the method. A thermochemistry calculated mixture of feed materials including aluminum granules, burnt limestone, and chromite ore are provided into a DC plasma arc furnace. The aluminum granules are produced from aluminum scrap. The feed materials are heated upon entering the furnace free board through a feed mix injection system, whereupon the aluminum in the aluminum granules produces an exothermic reaction reducing the chromium oxide and iron oxides in the chromite ore to produce molten low carbon ferrochrome metal with molten slag floating thereon. The molten low carbon ferrochrome metal is extracted, solidified into ingots, crushed into coarse pieces or fines of low carbon ferrochrome metal product. The molten slag is extracted, quenched and solidified into slag particles product.
ELECTRICAL STEEL SHEET HAVING INSULATING COATING, METHOD FOR PRODUCING THE SAME, TRANSFORMER CORE AND TRANSFORMER USING THE ELECTRICAL STEEL SHEET, AND METHOD FOR REDUCING DIELECTRIC LOSS IN TRANSFORMER
An electrical steel sheet having an insulating coating is provided. The electrical steel sheet is capable of reducing dielectric loss in a transformer in a case where the electrical steel sheet is used in a transformer core.
An electrical steel sheet having an insulating coating, the insulating coating being disposed on at least one of surfaces of the electrical steel sheet, the insulating coating having a relative dielectric constant at 1000 Hz of less than or equal to 15.0 and a dielectric loss tangent at 1000 Hz of less than or equal to 20.0.