A cold-rolled and heat-treated steel sheet, having a composition comprising, by weight percent: 0.10%≤C≤0.40%, 3.5%≤Mn≤8.0%, 0.5%≤Si≤2.5%, 0.003%≤Al≤3.0%, with Si+Al≥0.8%, 0.001%≤Mo≤0.5%, S≤0.010%, P≤0.020%, N≤0.008%, and optionally one or more elements selected from amongst Cr, Ti, Nb, V and B, such that: 0.01%≤Cr≤2.0%, 0.010%≤Ti≤0.080%, 0.010%≤Nb≤0.080%, 0.010%≤V≤0.30%, 0.0005%≤B≤0.003%, A remainder of the composition being iron and unavoidable impurities resulting from the smelting. The microstructure consists of, in surface fraction, between 10% and 50% of retained austenite, at most 8% of fresh martensite, and tempered martensite. The retained austenite comprises Mn-enriched austenite, having a Mn content higher than 1.3*Mn %, Mn % designating the Mn content of the steel sheet, the surface fraction of said Mn-enriched austenite with respect to the whole microstructure being comprised between 2% and 12%; and Mn-poor austenite, having a Mn content comprised between 0.5*Mn % and 1.3*Mn %.

A cold-rolled and heat-treated steel sheet, having a composition including, by weight percent: 0.10%≤C≤0.40%, 3.5%≤Mn≤8.0%, 0.5%≤Si≤2.5%, 0.003%≤Al≤3.0%, with Si+Al≥0.8%, 0.001%≤Mo≤0.5%, S≤0.010%, P≤0.020%, N≤0.008%, and optionally one or more elements selected from a group comprising Cr, Ti, Nb, V and B, such that: 0.01%≤Cr≤2.0%, 0.010%≤Ti≤0.080%, 0.010%≤Nb≤0.080%, 0.010%≤V≤0.30%, 0.0005%≤B≤0.003%, the remainder of the composition being iron and unavoidable impurities resulting from the smelting. The microstructure includes, in surface fraction, between 10% and 50% of retained austenite, at most 8% of fresh martensite, and tempered martensite. The retained austenite includes Mn-enriched austenite, having a Mn content higher than 1.3*Mn %, Mn % designating the Mn content of the steel sheet, a surface fraction of the Mn-enriched austenite with respect to the whole microstructure is between 2% and 12%, and Mn-poor austenite, having an Mn content between 0.5*Mn % and 1.3*Mn %.

Disclosed are an amorphous nanocrystalline soft magnetic material, a preparation method therefor and an application thereof, an amorphous ribbon material, an amorphous nanocrystalline ribbon material, and an amorphous nanocrystalline magnetic sheet. The soft magnetic material comprises an amorphous matrix phase, a nanocrystalline phase distributed in the amorphous matrix phase, and fine crystalline particles distributed in the amorphous matrix phase and the nanocrystalline phase. The amorphous matrix phase comprises Fe, Si, and B, the fine crystalline particles comprise metal carbides, and the soft magnetic material comprises Fe, Si, B, P, and Cu.

Provided is a steel plate for a pressure vessel with excellent cryogenic lateral expansion and a manufacturing method therefor.

The steel plate for a pressure vessel according to the present invention comprises, by wt %, 0.05 to 0.15% of C, 0.20 to 0.40% of Si, 0.3 to 0.6% of Mn, 0.015% or less of P, 0.015% or less of S, 0.02 to 0.10% of Al, 4.5 to 5.5% of Ni, 0.2 to 0.4% of Mo, 0.001 to 0.15% of Pd, with a remainder of Fe and inevitable impurities, and the steel plate has a steel microstructure comprising, by area fraction, 0.5 to 5.0% of retained austenite, 25 to 85% of tempered bainite, and a remainder of tempered martensite.

The invention concerns a method for manufacturing an aircraft part, the part comprising a monocrystalline nickel-based superalloy substrate, the method consecutively implementing the steps of moulding the part at a moulding temperature greater than the melting temperature of the superalloy, and cooling the part, such that the monocrystalline superalloy has a γ phase and a γ phase, solution heat treatment of the part at a first temperature between the solves temperature of the γ′ phase and the melting temperature of the superalloy, homogenising the crystalline structure or the part, cooling the part to ambient temperature, first tempering and second tempering.

Provided in the present disclosure is a method of heat treating a high-strength steel, wherein the high-strength steel comprises, by weight: 0.30-0.45% C, 1.0% or less Si, 0.20-2.5% Mn, 0.20-2.0% Cr, 0.15-0.50% Mo, 0.10-0.40% V, 0.2% or less Ti, 0.2% or less Nb, and a balance of Fe and other alloy elements and impurities, wherein the above alloy elements make Eq(Mn) according to the following formula (1) no less than 1.82, which method comprises the steps of 1) austenitizing; 2) carbide precipitation; and 3) tempering. The heat-treated steel in accordance with the present invention has high strength, high ductility and high toughness at the same time, especially improved reduction in area of tensile sample, so that it is particularly suitable for preparing spring members for vehicle suspension.

Eq(Mn)=Mn+0.26Si+3.50P+1.30Cr+2.67Mo  (1)

Apparatus and method for construction of a rectangular deep cryogenic treatment chamber using an insulated, steel structure capable of large size and large volume cold thermal treatment. Apparatus includes end or top-mounted closure, liquid nitrogen delivery and distribution mechanisms, fan motors, cold diffusion-less thermal exchange, external heating element, electrical wiring and machined components. The design facilitates both low temperature, dry vapor thermal processing of metal and metal-matrix components down to −320° F. to enhance wear, corrosion, mechanical, thermal and electrical characteristics, and also post-cryogenic tempering capability to 300° F. The apparatus describes an external, LN2 storage dewar and solenoid-activated, gravity fed cryogen delivery via distribution hubs and distributed flow tubes. The apparatus also describes integrated deep cryogenic treatment authentication, test, validation and certification equipment. The process and method of treatment results in certification documents that authenticate and confirm treatment of the subject parts, reflect test and measurement of improved characteristics, retained data for archival purposes and to provide scientific evidence and proof of such treatment to a third-party not present at time of treatments, test or certification

The present invention provides steel sheet products having controlled compositions that are subjected to two-step annealing processes to produce sheet products having desirable microstructures and favorable mechanical properties such as high strength and ultra-high formability. Steels processed in accordance with the present invention exhibit combined ultimate tensile strength and total elongation (UTS.Math.TE) properties of greater than 25,000 MPa-%. Steels with these properties fall into the category of Generation 3 advanced high strength steels, and are highly desired by various industries including automobile manufacturers.

The present invention provides steel sheet products having controlled compositions that are subjected to two-step annealing processes to produce sheet products having desirable microstructures and favorable mechanical properties such as high strength and ultra-high formability. Steels processed in accordance with the present invention exhibit combined ultimate tensile strength and total elongation (UTS.Math.TE) properties of greater than 25,000 MPa-%. Steels with these properties fall into the category of Generation 3 advanced high strength steels, and are highly desired by various industries including automobile manufacturers.

Provided are a hot dip galvanized steel sheet comprising a base steel sheet and a hot dip galvanized layer on at least one surface of the base metal steel sheet, wherein the base steel sheet has a predetermined chemical composition and contains, by volume fraction, ferrite: 0% to 50%, retained austenite: 6% to 30%, bainite: 5% or more, tempered martensite: 5% or more, fresh martensite: 0% to 10%, and pearlite and cementite in total: 0% to 5%, a number density of tempered martensite with a circle equivalent diameter of 5.0 μm or more is 20/1000 μm.sup.2 or less, and an area ratio of fresh martensite with a circle equivalent diameter of 2.0 μm or more after imparting 5% plastic strain is 10% or less, and a method for producing the same.