C21D9/52

Process for producing grain-oriented electrical steel strip and grain-oriented electrical steel strip obtained according to said process
20170283903 · 2017-10-05 ·

A process for producing grain-oriented electrical steel strip by means of thin slab continuous casting, comprising the following process steps: a) smelting a steel, b) continuously casting the smelt by thin slab continuous casting, c) heating up the thin slabs and subjecting the slabs to homogenization annealing at a maximum temperature of 1250° C., d) heating to a temperature between 1250° C. and 1350° C., e) continuously hot rolling the thin slabs to form a hot-rolled strip, f) cooling and reeling the hot-rolled strip to form a coil, g) annealing the hot-rolled strip after reeling and prior to a subsequent cold rolling step, h) cold rolling the hot-rolled strip to the nominal usable thickness, i) subjecting the cold-rolled strip to recrystallization, decarburization and nitridation annealing, j) applying an annealing separator (non-stick layer) to the strip surface of the cold-rolled strip, k) subjecting the cold-rolled strip to secondary recrystallization annealing, forming a finished steel strip having a pronounced Goss texture, and l) stress-free annealing the finished steel strip, which has been coated with an insulating layer, provides an improved process for producing grain-oriented electrical steel strip by means of thin slab continuous casting. This is achieved in that the recrystallization, decarburization and nitridation annealing of the cold-rolled strip in process step h) comprises a decarburization annealing phase and a subsequent nitridation annealing phase, with an intermediate reduction annealing phase being interposed between the decarburization annealing phase and the nitridation annealing phase, and carried out at a temperature ranging from 820° C.-890° C., for a maximum period of 40 seconds, with a dry, gaseous annealing atmosphere, which contains nitrogen (N.sub.2) and hydrogen (H.sub.2) and acts on the cold-rolled strip, and which has a water vapor/hydrogen partial pressure ratio pH.sub.2O/pH.sub.2 of less than 0.10.

Process for producing grain-oriented electrical steel strip and grain-oriented electrical steel strip obtained according to said process
20170283903 · 2017-10-05 ·

A process for producing grain-oriented electrical steel strip by means of thin slab continuous casting, comprising the following process steps: a) smelting a steel, b) continuously casting the smelt by thin slab continuous casting, c) heating up the thin slabs and subjecting the slabs to homogenization annealing at a maximum temperature of 1250° C., d) heating to a temperature between 1250° C. and 1350° C., e) continuously hot rolling the thin slabs to form a hot-rolled strip, f) cooling and reeling the hot-rolled strip to form a coil, g) annealing the hot-rolled strip after reeling and prior to a subsequent cold rolling step, h) cold rolling the hot-rolled strip to the nominal usable thickness, i) subjecting the cold-rolled strip to recrystallization, decarburization and nitridation annealing, j) applying an annealing separator (non-stick layer) to the strip surface of the cold-rolled strip, k) subjecting the cold-rolled strip to secondary recrystallization annealing, forming a finished steel strip having a pronounced Goss texture, and l) stress-free annealing the finished steel strip, which has been coated with an insulating layer, provides an improved process for producing grain-oriented electrical steel strip by means of thin slab continuous casting. This is achieved in that the recrystallization, decarburization and nitridation annealing of the cold-rolled strip in process step h) comprises a decarburization annealing phase and a subsequent nitridation annealing phase, with an intermediate reduction annealing phase being interposed between the decarburization annealing phase and the nitridation annealing phase, and carried out at a temperature ranging from 820° C.-890° C., for a maximum period of 40 seconds, with a dry, gaseous annealing atmosphere, which contains nitrogen (N.sub.2) and hydrogen (H.sub.2) and acts on the cold-rolled strip, and which has a water vapor/hydrogen partial pressure ratio pH.sub.2O/pH.sub.2 of less than 0.10.

METHOD FOR MANUFACTURING CURVED THIN-WALLED INTERMETALLIC COMPOUND COMPONENT BY WINDING MANDREL WITH METAL FOIL STRIPS
20220048090 · 2022-02-17 ·

The present invention provides a method for manufacturing a curved thin-walled intermetallic compound component by winding a mandrel with metal foil strips, which comprises the following steps: designing a prefabricated blank; preparing a support mandrel; determining thicknesses and layer numbers of foil strips; determining widths of the foil strips; establishing a laying process; pretreating surfaces of the foil strips; laying A foil and B foil; carrying out bulge forming on the prefabricated blank; carrying out diffusion reaction and densification treatment on a bulged component; and carrying out subsequent treatment of a thin-walled component. The present invention can solve the problems that impurities generated in the separation process of a support mould and a laminated foil prefabricated blank influence the final performance of a part, and a single homogeneous intermetallic compound component in thickness direction has poor plasticity and toughness at room temperature.

METHOD FOR PRODUCING HOT-FORMED STEEL SPRINGS

A process for producing a spring or torsion bar from a steel wire by hot forming may involve providing a steel wire; thermomechanically forming the steel wire; cooling the steel wire thermomechanically; cutting the steel wire to length to give rods; heating the rods; hot forming the rods; and tempering the rods to give a spring or torsion bar, comprising quenching the rods to give a spring or torsion bar to a first cooling temperature, reheating the spring or torsion bar to a first annealing temperature, and cooling the spring or rod to a second cooling temperature. Further, in some examples, the cooling of the steel wire may be cooled to a temperature below a minimum recrystallization temperature such that at least a partly ferritic-pearlitic structure is established in the steel wire.”

Method of producing a hot-rolled high-strength steel with excellent stretch-flange formability and edge fatigue performance

A method to manufacture a hot-rolled high-strength steel sheet or strip with tensile strength of 570 MPa or higher, or preferably 780 MPa or higher, or even more preferably 980 MPa or higher, with an excellent combination of tensile elongation, SFF, and PEF strength.

Method of producing a hot-rolled high-strength steel with excellent stretch-flange formability and edge fatigue performance

A method to manufacture a hot-rolled high-strength steel sheet or strip with tensile strength of 570 MPa or higher, or preferably 780 MPa or higher, or even more preferably 980 MPa or higher, with an excellent combination of tensile elongation, SFF, and PEF strength.

WEATHERING STEEL
20170240992 · 2017-08-24 ·

A method of making weathering steel by preparing a molten melt producing an as-cast carbon alloy steel strip with a corrosion index of at least 6.0 comprising, by weight, 0.02%-0.08% carbon, <0.6% silicon, 0.2%-2.0% manganese, <0.03% phosphorus, <0.01% sulfur, <0.01% nitrogen, 0.2%-0.5% copper, 0.01%-0.2% niobium, 0.01%-0.2% vanadium, 0.1%-0.4% chromium, 0.08%-0.25% nickel, <0.01% aluminum, and the remainder iron and impurities. The molten melt is solidified and cooled into a cast strip ≧4 mm in thickness in a non-oxidizing atmosphere. The strip is hot rolled in an austenitic temperature range above Ar.sub.3 to between 10% and 50% reduction, cooled at above 20° C./s and coiled below 700° C. to form a steel strip with a microstructure comprising bainite and acicular ferrite with more than 70% niobium in solid solution. Then, age hardening the strip resulting in a yield strength of at least 550 MPa and a total elongation of at least 8%.

WEATHERING STEEL
20170240992 · 2017-08-24 ·

A method of making weathering steel by preparing a molten melt producing an as-cast carbon alloy steel strip with a corrosion index of at least 6.0 comprising, by weight, 0.02%-0.08% carbon, <0.6% silicon, 0.2%-2.0% manganese, <0.03% phosphorus, <0.01% sulfur, <0.01% nitrogen, 0.2%-0.5% copper, 0.01%-0.2% niobium, 0.01%-0.2% vanadium, 0.1%-0.4% chromium, 0.08%-0.25% nickel, <0.01% aluminum, and the remainder iron and impurities. The molten melt is solidified and cooled into a cast strip ≧4 mm in thickness in a non-oxidizing atmosphere. The strip is hot rolled in an austenitic temperature range above Ar.sub.3 to between 10% and 50% reduction, cooled at above 20° C./s and coiled below 700° C. to form a steel strip with a microstructure comprising bainite and acicular ferrite with more than 70% niobium in solid solution. Then, age hardening the strip resulting in a yield strength of at least 550 MPa and a total elongation of at least 8%.

STEEL WIRE AND SPRING

A steel wire is formed of a steel containing: not less than 0.6 mass % and not more than 0.7 mass % carbon, not less than 1.2 mass % and not more than 2.1 mass % silicon, not less than 0.2 mass % and not more than 0.6 mass % manganese, not less than 1.4 mass % and not more than 2 mass % chromium, and not less than 0.15 mass % and not more than 0.3 mass % vanadium, with the balance being iron and unavoidable impurities. The steel includes a matrix made up of tempered martensite, and a non-metallic inclusion present in the matrix. When √area of the non-metallic inclusion is represented as H.sub.1 and √area of a region including both the non-metallic inclusion and a decreased-hardness portion is represented as H.sub.2, a ratio of H.sub.2 to H.sub.1, or, H.sub.2/H.sub.1 is at least 1 and less than 1.3.

Soft magnetic alloy ribbon and magnetic device

A soft magnetic alloy thin strip which has high saturation magnetic flux density and low coercivity, which enables a core with high space factor and high saturation magnetic flux density. A soft magnetic alloy thin strip including a main component that has a composition formula (Fe.sub.(1−(α+β))X1.sub.αX2.sub.β).sub.(1−(a+b+c+d+e+f))M.sub.aB.sub.bP.sub.cSi.sub.dC.sub.eS.sub.f. In the formula, X1, X2 and M are selected from a specific element group; 0≤a≤0.140, 0.020≤b≤0.200, 0≤c≤0.150, 0≤d≤0.090, 0≤e≤0.030, 0≤f≤0.030, α≥0, β≥0, and 0≤α+β≤0.50; and at least one of a, c and d is larger than 0. The strip has a structure that is composed of an Fe-based nanocrystal; and the surface roughness of a release surface satisfies 0.85≤Ra.sub.e/Ra.sub.c≤1.25 (wherein Ra.sub.c is the average of arithmetic mean roughnesses in the central portion, and Ra.sub.e is the average in the edge portion).