There is provided a non-oriented electrical steel sheet having a predetermined chemical composition, in which an area fraction of a crystal structure A composed of crystal grains having a grain size of 100 ?m or more is 1% to 30% in a cross section parallel to a rolled plane of the non-oriented electrical steel sheet, an average grain size of a crystal structure B which is a crystal structure other than the crystal structure A is 40 ?m or less, and a Vickers hardness HvA of the crystal structure A and a Vickers hardness HvB of the crystal structure B satisfy Equation 1 ((HvA.sup.2+HvB.sup.2)/2?(HvA+HvB).sup.2/4?7.0).

In a method of producing a grain-oriented electrical steel sheet comprising subjecting a steel slab containing no inhibitor-forming components to hot rolling, cold rolling, primary recrystallization annealing working also as decarburization and to final annealing causing secondary recrystallization after applying an annealing separator on the surface, the final cold rolling for cold rolling the steel sheet to the final thickness uses a warm rolling with a tandem rolling mill at a total rolling reduction of not less than 80% at 150 to 280? C. and is performed by extending a pass line length of the steel sheet between the stands so that T satisfies T?1.3?L/V, where an distance between the stands is defined as L(m), a speed of the steel sheet passing between the stands is defined as V (mpm), and a pass time during which the steel sheet passes between the stands is defined as T(min).

Provided is a method for manufacturing a high silicon steel sheet having excellent producibility and magnetic properties. The method includes: casting a molten metal as a strip having a thickness of 5 mm or less, the molten metal comprising, by weight %, C: 0.05% or less (excluding 0%), N: 0.05% or less (excluding 0%), Si: 4% to 7%, Al: 0.5% to 3%, Si+Al: 4.5% to 8%, and the balance of Fe and inevitable impurities; hot-rolling the cast strip at a temperature of 800 C. or higher; annealing the hot-rolled strip at a temperature within a range of 900 C. to 1200 C.; cooling the annealed strip; warm-rolling the quenched strip at a temperature within a range of 300 C. to 700 C.; and finally annealing the warm-rolled strip at a temperature within a range of 800 C. to 1200 C.

A component made of metallic composite material having high corrosion resistance and scale resistance. The metallic composite material contains as a core material an uncoated hardenable steel on which surface a corrosion resistance and scaling resistance layer is provided using heat resistant stainless steel, and has a yield strength Rp.sub.0,2 of at least 1000 MPa and a tensile strength R.sub.m of at least 1500 MPa for the core material and a critical scaling resistance temperature in air for the layer material is at least 850 C.

A soft magnetic steel sheet is manufactured by mixing an amount of molten scrap iron, an amount of substantially pure molten iron and an amount of substantially pure molten silicon so as to produce a molten alloy containing Fe as a base material, 1.0 to 7.0 wt % of Si, and 0.1 to 1.0 wt % of Cu, forming a soft magnetic steel sheet by subjecting the molten alloy to a liquid rapid cooling single roller process, and heat treating the soft magnetic steel sheet in an inert atmosphere at 600 to 1,200? C.

A grain oriented electrical steel sheet according to an exemplary embodiment of the present invention includes a grain oriented electrical steel sheet base material and a metal oxide layer present on both sides of the grain oriented electrical steel sheet base material. A maximum Al fraction in the metal oxide layer is 0.15 to 1.0 wt %, and a ratio (DW.sub.L/DW.sub.S) of an average magnetic domain width (DW.sub.L) of a side with a large average magnetic domain width to an average magnetic domain width (DW.sub.S) of a side with a small average magnetic domain width of one side and the other side of the electrical steel sheet base material is 1.2 to 1.8.

The present disclosure has as its object the provision of non-oriented electrical steel sheet excellent in magnetic properties which is free from any drop in magnetic flux density even after stress relief annealing and a method for manufacturing the same. Non-oriented electrical steel sheet having a chemical composition containing C: 0.0030 mass % or less, Si: 2.0 mass % or more and 4.0 mass % or less, Al: 0.010 mass % or more and 3.0 mass % or less, Mn: 0.10 mass % or more and 2.4% mass or less, P: 0.0050 mass % or more and 0.20 mass % or less, S: 0.0030 mass % or less, and one or more elements selected from the group comprising Mg, Ca, Sr, Ba, Ce, La, Nd, Pr, Zn, and Cd: total 0.00050 mass % or more and having a balance of Fe and unavoidable impurities, where, when designating a mass % of Si as [Si], a mass % of Al as [Al], and a mass % of Mn as [Mn], a parameter Q shown by the following formula (1) is 2.0 or more, a random intensity ratio of the {100} orientation is 2.4 or more, and an average grain size is 30 m or less:
Q=[Si]+2[Al][Mn](1).

A preparation method of glassless grain-oriented silicon steel includes the following operations. During a decarburization annealing, a thickness of an oxide film on a surface of strip is 1.5-2.5 m; an atomic weight ratio of Si element and Fe element in the oxide film satisfies: Si/(Si+Fe)0.76; during a high-temperature annealing, a cooling stage includes sequentially: cooling with an inner cover when a temperature drops from 1200 C. to 500 C.; wherein a protective gas is a mixed gas containing nitrogen and hydrogen, and a volume percentage of the hydrogen in the mixed gas is >3%; cooling with the inner cover when the temperature drops from 500 C. to 200 C.; wherein the protective gas is nitrogen; and cooling in air by removing the inner cover when the temperature is <200 C.

Provided is a method of manufacturing a grain-oriented electrical steel sheet with which a grain-oriented electrical steel sheet with excellent magnetic properties and little variation in iron loss in the longitudinal direction of a coil can be stably manufactured. The method includes subjecting a steel slab to hot-rolling and optionally to annealing, then performing cold rolling once or twice or more to obtain a cold-rolled sheet with a final sheet thickness, and then subjecting the cold-rolled sheet to decarburization annealing and then secondary recrystallization annealing, where immediately before final cold rolling, a steel sheet is heated at a heating rate of 100 C./s or more to a heating temperature of 100 C. or higher and 350 C. or lower, and a time from when the steel sheet reaches the heating temperature to when it is bitten in a first pass of final cold rolling is set to within 5 seconds.