177 results about "Area fraction" patented technology

A double cold rolled non-oriented electrical steel sheet having a composition including: 0.0001%≤Carbon≤0.007%, 0.1%≤Manganese≤0.2%, 3.1%≤Silicon≤3.6%, 0.8%≤Aluminum≤1.1%, Phosphorus≤0.15%, Sulfur≤0.006%, Nitrogen≤0.09%, and can contain various optional elements. The remainder composition being iron and unavoidable impurities caused by processing, the microstructure is made of ferrite and has in area fraction, 80% to 100% recrystallized microstructure, 0% to 20% non-recrystallized microstructure wherein the average grain size of recrystallized microstructure is from 20 microns to 110 microns and having a percentage of eddy current losses in total iron losses, measured at 1 T and 400 Hz according to IEC 60404-2 standards, is from 35% to 45% when calculated in accordance of Bertotti method and simultaneously having a magnetic polarization at 5000 A / m (J50) from 1.64 T to 1.66 T.

A non-oriented electrical steel sheet having a composition including of the following elements, expressed in percentage by weight: 0.0001%≤Carbon≤0.007%,, 0.15% ≤Manganese≤0.2%, 3%≤Silicon≤3.6%, 0.7%≤Aluminum≤1.3%, Phosphorus≤0.15%, Sulfur≤0.006%, Nitrogen≤0.09%, with 3.85%≤Si+Al+Mn ≤5.5%, and can contain various optional elements, the remainder composition being composed of iron and unavoidable impurities caused by processing, the microstructure of the steel sheet being made of ferrite and including in area fraction, 80% to 100% recrystallized microstructure, 0% to 20% non-recrystallized microstructure wherein the average grain size of recrystallized microstructure is from 20 microns to 110 microns and eddy current losses in total iron losses, measured at 1 T and 400 Hz according to IEC 60404-2 standards, of 35 to 55% when calculated in accordance with Bertotti method and simultaneously having a magnetic polarization at 5000 A / m (J50) from 1.635T to 1.670T.

A non-oriented electrical steel sheet having a composition including of the following elements, expressed in percentage by weight: 0.0001%≤Carbon≤0.007%, 0.15%≤Manganese≤0.25%, 3.2%≤Silicon≤3.8%, 0.7%≤Aluminum≤1.3%, Phosphorus≤0.15%, Sulfur≤0.006%, Nitrogen≤0.09%, and various optional elements. The remainder composition is iron and unavoidable impurities caused by processing. The microstructure is ferrite and has in area fraction, 80% to 100% recrystallized microstructure, 0% to 20% non-recrystallized microstructure wherein the average grain size of recrystallized microstructure is from 20 microns to 110 microns and having a percentage of eddy current losses in total iron losses, measured at 1 T and 400 Hz according to IEC 60404-2 standards, less than 33% when calculated in accordance with Bertotti method and simultaneously having a magnetic polarization at 5000 A / m (J50) from 1.630T to 1.65T.

A non-oriented electrical steel sheet having a composition including of the following elements, expressed in percentage by weight: 0.0001%≤Carbon≤0.007%, 0.21%≤Manganese≤0.7%, 3%≤Silicon≤3.6%, 0.7%≤Aluminum≤1.3%, Phosphorus≤0.15%, Sulfur≤0.006%, Nitrogen≤0.09%, with 3.85%≤Si+Al+Mn≤5.5%, and can contain various optional elements. The remainder composition being composed of iron and unavoidable impurities. The microstructure is ferrite and has in area fraction, 80% to 100% recrystallized microstructure, 0% to 20% non-recrystallized microstructure wherein the average grain size of recrystallized microstructure is from 20 microns to 110 microns and having a percentage of eddy current losses in total iron losses, measured at 1 T and 400 Hz according to IEC 60404-2 standards, from 35% to 45% and simultaneously having a magnetic polarization at 5000 A / m (J50) from 1.63T to 1.66T.

The invention deals with a non-oriented electrical steel sheet having a composition of the following elements, expressed in percentage by weight: 0.0001%≤Carbon≤0.007%, 0.05%≤Manganese≤0.15%, 2.5%≤Silicon≤3.1%, 0.26%≤ Aluminum≤0.7%, Phosphorus≤0.15%, Sulfur≤0.006%, Nitrogen≤0.09%, and can contain various optional elements. The remainder composition is composed of iron and unavoidable impurities caused by processing. The microstructure of the steel sheet is made of ferrite and has in area fraction, 80% to 100% recrystallized microstructure, 0% to 20% non-recrystallized microstructure wherein the average grain size of recrystallized microstructure is from 20 microns to 110 microns and having a percentage of eddy current losses in total iron losses, measured at 1 T and 400 Hz according to IEC 60404-2 standards, from 35% to 45% when calculated in accordance of Bertotti method.

A non-oriented electrical steel sheet having a composition including of the following elements, expressed in percentage by weight: 0.0001% ≤ Carbon≤0.007%, 0.17%≤Manganese≤0.4%, 3%≤Silicon≤3.6%, 0.7%≤Aluminum≤1.3%, Phosphorus≤0.15%, Sulfur≤0.006%, Nitrogen≤0.09%, with 3.85%≤Si+Al+Mn≤5.5% and can contain various optional elements the remainder composition being composed of iron and unavoidable impurities caused by processing, the microstructure of the steel sheet being made of ferrite and including in area fraction, 80% to 100% recrystallized microstructure, 0% to 20% non-recrystallized microstructure wherein the average grain size of recrystallized microstructure is from 20 microns to 110microns and having a percentage of eddy current losses in total iron losses, measured at 1 T and 400 Hz according to IEC 60404-2 standards, less than 25% when calculated in accordance of Bertotti method.

The invention discloses an Al-Mg-Zn aluminum alloy plate with excellent strong plasticity and light weight characteristics as well as a preparation method and application of the Al-Mg-Zn aluminum alloy plate. The alloy comprises the following components in percentage by mass: 5.0%-5.5% of Mg, 1.5%-2.0% of Zn, 0.4%-0.5% of Mn, 0.1%-0.3% of Cu, 0.15%-0.25% of Sc, 0.1%-0.15% of Zr, 0.05%-0.15% of Ag, less than or equal to 0.1% of impurities and the balance of Al. The density is not more than 2.63 g / cm < 3 >, the tensile strength is not less than 470 MPa, and the ductility is not less than 23%. The preparation method comprises the steps of high-purity raw material smelting and casting, two-stage homogenization, hot rolling, intermediate annealing, cold rolling, solid solution treatment and single-stage aging. Wherein the total pressing amount of hot rolling is 80-85%, the total pressing amount of cold rolling is 20-35%, and the single-stage aging time is 120-140 DEG C * 16-24 h. The microstructure of the alloy is characterized in that the average size of dispersed AlSc particles is smaller than or equal to 100 nm, the area fraction of deformed grains is larger than or equal to 70%, the average size of nanometer beta-AlMg and T-Mg (Al, Zn) composite precipitated phases is smaller than or equal to 20 nm, the number density is larger than or equal to 1 * 10 < m >, the area fraction of micron-order second phases is smaller than or equal to 0.5%, and the alloy is only formed by impurity Fe. According to the method, the traditional two-stage aging process is simplified, low density, high strength and high plasticity are synchronously improved, and the method is suitable for large-scale industrial application.

A non-oriented electrical steel sheet having a composition of the following elements, expressed in percentage by weight: 0.0001%≤Carbon≤0.007%, 0.09%≤Manganese≤0.15%, 2.5%≤Silicon≤3%, 0.1% ≤ Aluminum≤0.5%, Phosphorus≤0.15%, Sulfur≤0.006%, Nitrogen≤0.09%, and can contain various optional elements, the remainder composition being composed of iron and unavoidable impurities caused by processing, the microstructure of the steel sheet being made of ferrite and including in area fraction, 80% to 100% recrystallized microstructure, 0% to 20% non-recrystallized microstructure wherein the average grain size of recrystallized microstructure is from 20 microns to 110 microns and having a percentage of eddy current losses in total iron losses, measured at 1 T and 400 Hz according to IEC 60404-2 standards, from 35% to 45% when calculated in accordance of Bertotti method.

A non-oriented electrical steel sheet having a composition including of the following elements, expressed in percentage by weight: 0.0001%≤Carbon≤0.007%, 0.18%≤Manganese≤0.5%, 3.1%≤Silicon≤3.8%, 0.7%≤Aluminum≤1.3%, Phosphorus≤0.15%, Sulfur≤0.006%, Nitrogen≤0.09%, with 3.85%≤Si+Al+Mn≤5.5%, and can contain various optional elements the remainder composition being composed of iron and unavoidable impurities caused by processing, the microstructure of the steel sheet being made of ferrite and including in area fraction, 80% to 100% recrystallized microstructure, 0% to 20% non-recrystallized microstructure wherein the average grain size of recrystallized microstructure is from 20 microns to 110 microns and having a percentage of eddy current losses in total iron losses, measured at 1 T and 400 Hz according to IEC 60404-2 standards, less than 34% when calculated in accordance with Bertotti method and simultaneously having a magnetic polarization at 5000 A / m (J50) from 1.60 T to 1.65 T.

A non-oriented electrical steel sheet having a composition including the following elements, expressed in percentage by weight: 0.0001%≤Carbon≤0.007%, 0.15%≤Manganese≤0.7%, 3%≤Silicon≤3.6%, 0.7%≤Aluminum≤1.3%, Phosphorus≤0.15%, Sulfur≤0.006%, Nitrogen≤0.09%, with 3.85%≤Si+Al+Mn≤5.5%, and can contain various optional elements, the remainder composition being composed of iron and unavoidable impurities caused by processing, the microstructure of the steel sheet being made of ferrite and including in area fraction, 80% to 100% recrystallized microstructure, 0% to 20% non-recrystallized microstructure wherein the average grain size of recrystallized microstructure is from 20 microns to 110 microns and having a percentage of eddy current losses in total iron losses, measured at 1 T and 400 Hz according to IEC 60404-2 standards, from 30 to 40% when calculated in accordance with Bertotti method.

A metal powder having a composition including the following elements, expressed in content by weight: 6.5%≤Si≤10%, 4.5%≤Nb≤10%, 0.2%≤B≤2.0%, 0.2%≤Cu≤2.0%, C≤2% and optionally containing Ni≤10 wt % and / or Co≤10 wt % and / or Cr≤7 wt % and / or Zr as a substitute for any part of Nb on a one-to-one basis and / or Mo as a substitute for any part of Nb on a one-to-one basis and / or P as a substitute for any part of Si on a one-to-one basis, the balance being Fe and unavoidable impurities resulting from the elaboration, the metal powder having a microstructure including at least 5% in area fraction of an amorphous phase, the balance being made of crystalline ferritic phases with a grain size below 20 μm and possible precipitates, the metal powder having a mean sphericity SPHT of at least 0.80.

A non-oriented electrical steel sheet having a composition including of the following elements, expressed in percentage by weight: 0.0001%≤Carbon≤0.007%, 0.15%≤Manganese≤0.2%, 3%≤Silicon≤3.6%, 0.7%≤Aluminum≤1.3%, Phosphorus≤0.15%, Sulfur≤0.006%, Nitrogen≤0.09%, with 3.85%≤Si+Al+Mn≤5.5%, various optional elements. The remainder composition is iron and unavoidable impurities caused by processing. The microstructure is made of ferrite and has in area fraction, 80% to 100% recrystallized microstructure, 0% to 20% non-recrystallized microstructure wherein the average grain size of recrystallized microstructure is from 20 microns to 110 microns and eddy current losses in total iron losses, measured at 1 T and 400 Hz according to IEC 60404-2 standards, of 35 to 55% when calculated in accordance with Bertotti method and simultaneously having a magnetic polarization at 5000A / m (J50) from 1.635T to 1.670T.

A Zn—Al—Mg-based hot-dip plated steel sheet includes a hot-dip plated layer formed on a surface of a steel sheet, in which the hot-dip plated layer contains, as an average composition, Al: 5 to 22 mass % and Mg: 1.0 to 10 mass %, with a remainder including Zn and impurities, and in a case where a 5 mm square cross section parallel to a surface of the hot-dip plated layer is exposed at any position of a 3t / 4 position, a t / 2 position, and a t / 4 position from the surface with a thickness of the hot-dip plated layer represented by t, a ratio (B / A (%)) of an area fraction B of a [Zn phase] to a total area fraction A of a [Zn phase] and an [Al / MgZn2 / Zn ternary eutectic structure] of a plating microstructure in at least one cross section is 20% or more.

A non-oriented electrical steel sheet having a composition including, expressed in percentage by weight: 0.0001%≤Carbon≤0.005%, 0.2%≤Manganese≤0.3%, 3.1%≤Silicon≤3.6%, 0.6%≤Aluminum≤1%, Phosphorus≤0.15%, Sulfur≤0.006%, Nitrogen≤0.09%, and can contain various optional elements. The remainder composition being iron and unavoidable impurities caused by processing, the microstructure is made of ferrite and has in area fraction, 80% to 100% recrystallized microstructure, 0% to 20% non-recrystallized microstructure wherein the average grain size of recrystallized microstructure is from 20 microns to 110 microns and having a percentage of eddy current losses in total iron losses, measured at 1 T and 400 Hz according to IEC 60404-2 standards, from 30% to 35% when calculated in accordance of Bertotti method.

The present application relates to single crystal superalloy blade recrystallization detection technical field, disclose a kind of single crystal superalloy blade recrystallization detection method, device and equipment, the method includes: constructing single crystal superalloy recrystallization database;The single crystal superalloy creep sample containing recrystallization is subjected to creep test to obtain corresponding single crystal superalloy and corresponding blade under corresponding service condition recrystallization damage tolerance;The coordinate information of the deformed position of the single crystal superalloy blade to be detected is obtained;Corresponding parameters are input into database to obtain the cross-sectional recrystallization area fraction and maximum recrystallization depth of the deformed position of the single crystal superalloy blade;Whether the cross-sectional recrystallization area fraction and maximum recrystallization depth of the deformed position obtained are less than the corresponding recrystallization damage tolerance is judged to obtain detection result.The detection accuracy is high, the yield is improved, and the production quality acceptance standard of single crystal superalloy blade or test bar, nondestructive testing is expanded to provide reference.

A non-oriented electrical steel sheet having a composition of the following elements, expressed in percentage by weight 0.0001%≤Carbon≤0.007%, 0.15%≤Manganese≤0.25%, 2.9%≤Silicon≤3.4%, 0.8%≤Aluminum≤1.1%, Phosphorus≤0.15%, Sulfur≤0.006%, Nitrogen≤0.09%, with 3.85%≤Si+Al+Mn≤5.5%, and the following optional elements 0%≤Niobium≤0.1%, 0%≤Titanium≤0.1%, 0%≤Vanadium≤0.1%, 0%≤Chromium≤1%, 0%≤Molybdenum≤0.5%, 0%≤Tungsten≤0.1%, 0%≤Cobalt≤1%, 0%≤Arsenic≤0.05%, 0.001%≤Calcium≤0.01%, 0%≤Copper≤1%, 0%≤Nickel≤1%, 0%≤Boron≤0.05%, 0%≤Lead≤0.2%, 0%≤Tin≤0.2%, 0%≤Antimony≤0.2%, the remainder composition being composed of iron and unavoidable impurities caused by processing. The microstructure is made of ferrite and including in area fraction, 80% to 100% recrystallized microstructure, 0% to 20% non-recrystallized microstructure wherein the average grain size of recrystallized microstructure is from 20 microns to 110 microns and having a percentage of eddy current losses in total iron losses less than 25% and simultaneously having a magnetic polarization at 5000 A / m from 1.625 T to 1.690 T.

Methods for producing a glass that contains no bubbles with diameters of more than 0.1 mm and in which the occupied area fraction of bubbles with diameters of 0.1 mm or less is 0.05% or less, the methods including: placing raw material powders for at least one oxide of Si and a di- or higher-valent metal element in a container, mixing the raw material powders together and then melting the mixture by heating under reduced pressure to obtain a melt; pressurizing the melt in a He gas atmosphere, or heating the melt in an inert gas atmosphere other than a He gas atmosphere and then pressurizing the melt in the inert gas atmosphere; and cooling the melt.

A steel sheet has a certain chemical composition and a steel microstructure containing, in area fraction, martensite: 40% or more and 78% or less, bainite: 20% or more and 58% or less, and retained austenite: 2% or more. Carbides in tempered martensite in the martensite have an average particle size of 0.40 μm or less, an average amount of C in the retained austenite is 0.5% by mass or more, a Si concentration in a region within 100 μm in a thickness direction from a surface of the steel sheet is 1.3% by mass or less, and a tensile strength is 1,470 MPa or more.

Non-grain-oriented electrical steel sheet, having a thickness of 0.30 mm to 0.38 mm and a composition comprising the following elements, expressed as weight percent: 0.0001% ≤ Carbon ≤ 0.007% 0.09% ≤ Manganese ≤ 0.15% 2.6% ≤ Silicon ≤ 2.95% 0.1% ≤ Aluminum ≤ 0.5% Phosphorus ≤ 0.15% Sulfur ≤ 0.006% Nitrogen ≤ 0.09% 0% ≤ Tin ≤ 0.04% and may contain one or more of the following optional elements: 0% ≤ Niobium ≤ 0.1% 0% ≤ Titanium ≤ 0.1% 0% ≤ Vanadium ≤ 0.1% 0% ≤ Chromium ≤ 1% 0% ≤ Molybdenum ≤ 0.5% 0% ≤ Tungsten ≤ 0.1% 0% ≤ Cobalt ≤ 1% 0% ≤ Arsenic ≤ 0.05% 0.001% ≤ Calcium ≤ 0.01% 0% ≤ Copper ≤ 1% 0% ≤ Nickel ≤ 1% 0% ≤ Boron ≤ 0.05% 0% ≤ Lead ≤ 0.2% 0% ≤ Antimony ≤ 0.2% wherein the remaining composition consists of iron and unavoidable impurities caused by processing, wherein the microstructure of the steel sheet consists of ferrite, comprising 80% to 100% recrystallized microstructure and 0% to 20% non-recrystallized microstructure in area fractions, wherein the average grain size of the recrystallized microstructure is 20 to 110 micrometers, and exhibiting a percentage of eddy current losses in the total iron losses, measured at 1 T and 400 Hz according to standards IEC 60404-2, of 35% to 45%, calculated according to the Bertotti method.

The application provides a method for regulating microstructure of hot-dip galvanizing zinc-aluminum-magnesium alloy through directional solidification technology, and belongs to the technical field of hot-dip plating. The technical problem solved by the application is that, in the actual production process, the accurate control of the cooling process cannot be realized, which leads to serious deficiencies in the accurate regulation of the solidification behavior and the alloy structure of the zinc-aluminum-magnesium coating. The technical scheme adopted by the application is that the coating surface temperature in each cooling process in the actual production process is measured, and the corresponding simulation results are combined to obtain the coating cooling parameters in the actual production process, and on this basis, the directional solidification test parameters are designed, so that the regulation of the microstructure of the hot-dip galvanizing zinc-aluminum-magnesium alloy through the directional solidification technology is realized. The method provided by the application can regulate the phase composition and the area fraction of the eutectic structure of the hot-dip galvanizing zinc-aluminum-magnesium alloy under different cooling processes through the directional solidification technology, so as to provide important theoretical guidance for improving the hot-dip galvanizing zinc-aluminum-magnesium process in the actual production process.

The present invention provides a steel sheet comprising, by wt%, carbon (C): 0.11% - 0.14%, silicon (Si): 0.1% - 0.3%, manganese (Mn): 0.9% - 1.3%, soluble aluminum (Sol. Al): 0.015% - 0.055%, phosphorus (P): 0 (exclusive) - 0.015% (inclusive), sulfur (S): 0 (exclusive) - 0.003% (inclusive), nickel (Ni): 1.7% - 2.2%, chromium (Cr): 0.2% - 0.6%, and molybdenum (Mo): 0.2% - 0.6%, with the balance being iron and inevitable impurities, wherein the microstructure of the heat-affected zone in welding has a maximum size of effective grain of 50 μm or less with a grain boundary misorientation angle of 15° or more, and comprises, by area fraction, 90–98% of lower bainite and upper bainite in total, and less than 5% of martensite-austenite constituent.

A cold-rolled steel sheet having a composition comprising 0.05% < = carbon < = 0.15%, 1.8% < = manganese < = 2.7%, 0.1% < = silicon < = 1%, 0.01% < = aluminum < = 0.8%, 0.1% < = chromium < = 0.9%, 0% < = phosphorus < = 0.09%, 0.0001% < = titanium < = 0.1%, 0.0005% < = boron < = 0.003%, 0.01% < = niobium < = 0.1%, 0% < = sulfur < = 0.09%, 0% < = nitrogen < = 0.09%, 0% < = vanadium < = 0.2%, 0% < = molybdenum < = 0.2%, 0% < = nickel < = 2%, 0% < = copper < = 2%, 0% < = calcium < = 0.005%, 0% < = cerium < = 0.1%, 0% < = magnesium < = 0.05%, the microstructure of the steel sheet contains, in area fraction, 40% to 60% of martensite, 15% to 40% of critical zone ferrite, 10% to 35% of cumulant transformed ferrite and bainite, and 0% to 5% of retained austenite.

Double-rolled non-grain-oriented electrical steel sheet, having a thickness of 0.28 mm to 0.32 mm and having a composition comprising the following elements, expressed as weight percent: 0.0001% ≤ Carbon ≤ 0.007% 0.2% ≤ Manganese ≤ 0.24% 3.1% ≤ Silicon ≤ 3.5% 0.8% ≤ Aluminum ≤ 1.1% Phosphorus ≤ 0.15% Sulfur ≤ 0.006% Nitrogen ≤ 0.09% 0.01% ≤ Chromium ≤ 1% 0.01% ≤ copper ≤ 1% and may contain one or more of the following optional elements 0% ≤ Niobium ≤ 0.1% 0% ≤ Titanium ≤ 0.1% 0% ≤ Vanadium ≤ 0.1% 0% ≤ Molybdenum ≤ 0.5% 0% ≤ Tungsten ≤ 0.1% 0% ≤ Cobalt ≤ 1% 0% ≤ Arsenic ≤ 0.05% 0.001% ≤ Calcium ≤ 0.01% 0.001% ≤ Nickel ≤ 0.04% 0% ≤ Boron ≤ 0.05% 0% ≤ Lead ≤ 0.2% 0% ≤ Tin ≤ 0.2% 0% ≤ Antimony ≤ 0.2% wherein the remaining composition consists of iron and unavoidable impurities caused by processing, wherein the microstructure of the steel sheet consists of ferrite, comprising 80% to 100% recrystallized microstructure and 0% to 20% non-recrystallized microstructure in area fractions, wherein the average grain size of the recrystallized microstructure is 20 to 110 micrometers, and exhibiting a percentage of eddy current losses to the total iron losses, measured at 1 T and 400 Hz according to standards IEC 60404-2, of 30% to 35%, calculated according to the Bertotti method, and simultaneously a magnetic polarization at 5000 A / m (J50) of 1.645 T to 1.660 T.

The purpose of the present invention is to provide a technology relating to a steel sheet for cold press forming and a method for manufacturing same, the steel sheet having high impact resistance after being subjected to cold press forming and being formed into a part.　The steel sheet for cold press forming has a specific component composition and a steel microstructure. The concentration of carbon in retained austenite satisfies 0.45-0.95%. In a tensile test according to JIS Z2241, the retained austenite that disappears during deformation between the start of the tensile test and the application of 1% nominal strain is 0.8% or more in area fraction relative to the total steel microstructure, and the retained austenite present after deformation from the start of the tensile test to uniform elongation is 3% or more in area fraction relative to the total steel microstructure.

This invention discloses a method for quantitatively evaluating the dispersion of MnS inclusions in steel, comprising the following steps: (1) preparing a metallographic sample of the steel and detecting the mass fraction of S in the metallographic sample; (2) calculating the theoretical volume fraction of MnS in the metallographic sample based on the S content; (3) examining the metallographic sample for MnS inclusions using a metallographic microscope and recording the area of ​​MnS inclusions, the area of ​​the field of view, and the total number of fields of view for each field of view; (4) calculating the area fraction of MnS inclusions in each field of view; (5) calculating the deviation of the detected MnS volume fraction from the theoretical MnS volume fraction in each field of view; (6) calculating the standard deviation of the deviation of MnS inclusions in each field of view, and defining the standard deviation of the deviation as a quantitative evaluation index for the dispersion of MnS inclusions. This method accurately establishes a linear relationship between the distribution of MnS inclusions in steel and the S content in steel, thereby improving the accuracy of MnS inclusion evaluation.

To provide a steel for bolt that attains sufficiently low hardness even when omitting softening annealing, and thus enables adequately high cold workability.SOLUTION: A steel for bolt having a predetermined chemical composition, wherein the metallographic structure includes ferrite and pearlite, the total of those being 95.0 area% or more, and the ferrite area fraction being 54.0 area% or more. The steel satisfies the following formulas (1) and (2): Hvf≤200 (1) and Hvp×(1-Vf / 100)<-0.7358×Hvf×Vf / 100+200.79 (2), where Hvf is the Vickers hardness of ferrite, Hvp is the Vickers hardness of pearlite, and Vf is the area fraction of ferrite.SELECTED DRAWING: Figure 1

This invention relates to a high-temperature corrosion-resistant Fe-Cr-Mo-Ni alloy, its preparation method, and its applications. The alloy composition is 37%–40% Ni, 19%–29% Cr, and 5%–10.27% Mo, with the balance being Fe and trace impurities. X-ray diffraction of the alloy reveals a single-phase face-centered cubic structure. After holding at 800℃ for 400 hours, the area fraction of the σ phase in the microstructure does not exceed 5%. The breakdown potential in 3.5% NaCl solution is as high as 1.029 V, and its pitting corrosion resistance is superior to commercial 904L stainless steel. This alloy shows great promise for industrial application in the preparation of high-temperature resistant structural components operating under high corrosion conditions above 400–900℃, especially in service environments containing chloride ions, fluoride ions, or sulfides.

The purpose of the present invention is to provide a steel sheet having high strength, high ductility, and low yield elongation, and a method for manufacturing the same. A steel sheet having a component composition containing, in mass%, 0.03% to 0.15% (inclusive) of C, 0.05% or less of Si, 0.10% to 0.60% (inclusive) of Mn, 0.025% or less of P, 0.020% or less of S, 0.20% or less of Al, 0.0001% to 0.0200% (inclusive) of N, 0.005% to 0.030% (inclusive) of Nb, and more than 0.020% but 0.200% (inclusive) of Cu, the remainder being Fe and unavoidable impurities, the microstructure of the steel sheet having a ferrite content of 80% or more in area fraction, the steel sheet has a yield stress of 500 MPa or more, a tensile strength of 500 MPa or more, an HR30T of 68 or more, an elongation at break of 15% or more, and a yield elongation of 4.5% or less.

The invention relates to a double cold-rolled non-oriented electrical steel sheet having a composition comprising the following elements, expressed in percentage by weight: 0.0001% < = carbon < = 0.007%, 0.1% < = manganese < = 0.3%, 3.1% < = silicon < = 3.8%, 0.6% < = aluminum < = 0.8%, phosphorus < = 0.15%, sulfur < = 0.006%, nitrogen < = 0.09%, and the balance being iron and unavoidable impurities. And may comprise one or more of the following optional elements: 0% < = niobium < = 0.1%, 0% < = titanium < = 0.1%, 0% < = vanadium < = 0.1%, 0% < = chromium < = 1%, 0% < = molybdenum < = 0.5%, 0% < = tungsten < = 0.1%, 0% < = cobalt < = 1%, 0% < = arsenic < = 0.05%, 0.001% < = calcium < = 0.01%, 0% < = copper < = 1%, 0.001% < = nickel < = 0.01, 0% < = boron < = 0.05%, 0% < = lead < = 0.2%, 0% < = tin < = 0.2%, 0% < = antimony < = 0.2%, and the balance being Fe. A steel sheet having a microstructure composed of ferrite and including, in area fraction, 80% to 100% of a recrystallized microstructure having an average grain size of 20 [mu] m to 110 [mu] m and 0% to 20% of a non-recrystallized microstructure having an average grain size of 10 [mu] m to 100 [mu] m, the remainder being composed of iron and unavoidable impurities resulting from processing, the steel sheet having a microstructure composed of ferrite and having an average grain size of 10 [mu] m to 100 [mu] m, and a non-recrystallized microstructure having an average grain size of 10 [mu] m to 100 [ and the double cold-rolled non-oriented electrical steel sheet has a percentage of eddy current loss in the total iron loss measured at 1 T and 400 Hz according to IEC 60404-2 standard when calculated according to the Bertotti method of 40% to 50% and at the same time has a magnetic polarization (J50) at 5000 A / m of 1.66 T to 1.7 T.

Provided are a steel sheet and a member, having high strength and high delayed fracture resistance, and methods for manufacturing the steel sheet and the member. The steel sheet has a specific chemical composition and a microstructure in which the area fraction of martensite is 95% to 100%, with the balance being one or more of bainite, ferrite, and retained austenite. In the steel sheet, prior-austenite grains have an average grain size of 18 μm or less, 90 mass % or more of the total content of Nb and Ti contained is present as a carbonitride having an equivalent circular diameter of 100 nm or more, and a Nb carbonitride and a Ti carbonitride, having an equivalent circular diameter of 1.0 μm or more, are present at a rate of 800 pieces / mm2 or less in total. The steel sheet has a tensile strength of 1310 MPa or more.