190 results about "Iron based alloy" patented technology

The invention relates to a high-performance non-quenched and tempered steel bar for a fan shaft and a manufacturing method of the high-performance non-quenched and tempered steel bar, and belongs to the field of iron-based alloys. The steel comprises the following chemical components in percentage by weight: 0.37 to 0.43 percent of C, 0.30 to 0.60 percent of Si, 1.20 to 1.70 percent of Mn, less than or equal to 0.025 percent of P, 0.030 to 0.070 percent of S, less than or equal to 0.50 percent of Cr, 0.10 to 0.30 percent of Ni, less than or equal to 0.30 percent of Mo, less than or equal to 0.30 percent of Cu, 0.010 to 0.030 percent of Al, 0.005 to 0.025 percent of Ti, 0.05 to 0.15 percent of V, 0.0100 to 0.0200 percent of N, less than or equal to 0.0002 percent of H, less than or equal to 0.0015 percent of O and the balance of Fe and inevitable impurity elements. The manufacturing process comprises the steps of converter / electric furnace smelting, LF furnace refining, RH / VD furnace vacuum degassing, continuous casting, casting blank reheating, cogging rolling, flame cleaning, intermediate blank finishing, intermediate blank heating, bar rolling, cooling and stress relief tempering. The total cross-section structure of the bar is a ferrite and pearlite structure. The bending degree per meter is smaller than or equal to 0.5 mm, the surface defect depth is smaller than or equal to 0.10 mm, and the internal quality meets the A-level requirement of the GB / T4162 standard.

The invention discloses a preparation method for laser cladding of an iron-based alloy wear-resistant coating on the surface of an automobile brake disc, which comprises the following steps: (1) before cladding, putting iron-based alloy powder into a drying oven at 60 DEG C and drying for 120 minutes; (2) pretreating a matrix sample, removing rust and an oxide layer on the surface, cleaning the surface with absolute ethyl alcohol, and wiping to keep the surface dry; and (3) setting cladding process parameters, wherein the cladding process parameters comprise laser power, powder feeding amount, scanning speed, lap joint rate and scanning linear speed. And (4) a cladding experiment is started, and a cladding scanning path and mode are set, wherein the cladding scanning path and mode comprise a single-channel coating, a multi-channel lap joint coating and a whole-surface brake disc. And (5) after cladding is finished, waiting for natural cooling of the brake disc. The iron-based powder is used for preparing the coating on the surface of the automobile brake disc, technological parameters are optimized, the cladding procedure is simplified, the powder cost is low, the prepared coating is good in performance, and a single-layer coating scheme is provided for strengthening and repairing the brake disc.

The invention discloses a medium-entropy (Zr, Ta, W) C coating and a preparation method and application thereof. The medium-entropy (Zr, Ta, W) C gradient coating is prepared on the surface of the titanium alloy or the iron-based alloy through the double-layer glow plasma surface metallurgy technology, and gradient temperature annealing treatment is conducted. The preparation method has the specific advantages that (1) the prepared coating is of a continuous gradient structure, good interface metallurgical bonding is formed between the coating and a matrix, the bonding force of the coating is not lower than 50 N, and the coating is not prone to cracking and stripping in the service process due to the high bonding strength; and (2) the hardness of the medium-entropy (Zr, Ta, W) C coating prepared by the method is 25-30 GPa, the fracture toughness is 4.0-5.0 MPa * m < 1 / 2 >, and the coating system has balanced hardness and toughness, so that the coating is endowed with excellent wear resistance. The prepared coating has excellent wear resistance and antifriction performance, and has wide application prospects in the field of wear-resistant protective coatings.

The invention relates to medium-carbon alloy steel for a large industrial bearing and a production method of the medium-carbon alloy steel, and belongs to the field of iron-based alloy. The round steel comprises the following chemical components: 0.44 to 0.50 percent of C, 0.15 to 0.35 percent of Si, 0.60 to 0.90 percent of Mn, 1.0 to 1.30 percent of Cr, 0.5 to 0.9 percent of Ni, 0.25 to 0.40 percent of Mo, 0.05 to 0.10 percent of V, less than or equal to 0.20 percent of Cu, less than or equal to 0.05 percent of Al, less than or equal to 0.0008 percent of Ca, less than or equal to 0.008 percent of S, less than or equal to 0.015 percent of P, less than or equal to 0.0020 percent of Ti, less than or equal to 0.0012 percent of O, less than or equal to 0.03 percent of As, less than or equal to 0.03 percent of Sn, less than or equal to 0.005 percent of Sb, less than or equal to 0.002 percent of Pb and the balance of Fe and inevitable impurities. The production process comprises the steps of molten iron pretreatment, converter smelting, LF refining, RH refining, CCM continuous casting round billet, annealing and finishing. Forging with the compression ratio of 6 or above is adopted, and the grain size is larger than or equal to 6 grades. And on the basis of meeting the quality requirement of the steel for the medium-carbon bearing, the production cost is lower, and the steel has very strong market competitiveness.

The invention relates to an automotive frame steel plate with tensile strength of 750MPa and a hot rolling control method thereof, and belongs to the technical field of iron-based alloys. The steel plate comprises the following chemical components in percentage by mass: 0.05-0.08% of C, 0.1-0.3% of Si, 1.7-2.0% of Mn, less than or equal to 0.025% of P, less than or equal to 0.0030% of S, 0.05-0.1% of Ti, 0.04-0.08% of Nb, less than or equal to 0.0060% of N, 0.02-0.06% of Al, 0.3-0.7% of Mo, less than or equal to 0.0050% of Ca and the balance of iron and inevitable impurities. During hot rolling, the continuous casting sheet billet is controlled to be heated to 1250-1350 DEG C and then rolled, the rough rolling finish rolling temperature is 1050-1000 DEG C, the finish rolling finish rolling temperature is 880-900 DEG C, the reduction rate is larger than or equal to 60%, laminar cooling after rolling adopts front-section cooling, the cooling speed is 40-50 DEG C / s, and a hot rolled steel coil is obtained through coiling when the coiling temperature is 600-650 DEG C. Through proper chemical component design and hot rolling process condition control, the high-strength hot-rolled acid-washed automobile beam steel plate with the yield strength of 700-800 MPa and the tensile strength of 770-850 MPa is obtained.

The invention relates to a thick hot-rolled spring wide steel plate, and belongs to the field of iron-based alloys. The steel comprises the following chemical components in percentage by mass: 0.47 to 0.55 percent of C, 0.17 to 0.37 percent of Si, 0.70 to 1.10 percent of Mn, 0.90 to 1.20 percent of Cr, 0.10 to 0.25 percent of V, less than or equal to 0.020 percent of P, less than or equal to 0.010 percent of S and the balance of Fe and inevitable impurities, and the structure is uniform ferrite and pearlite. The production thickness ranges from 41 mm to 55 mm, the width is larger than 2000 mm, and the length is not smaller than 6000 mm; the straightness is less than or equal to 3mm / m, and the thickness tolerance range is within 1mm. The hardness is smaller than 280 HBW, the inclusions A, B, C and D are all smaller than 1.5 grades, and the sum of the inclusions A, B, C and D is smaller than or equal to 3.0 grades and is larger than or equal to 2.0 grades. High purity, longitudinal and transverse performance uniformity and accurate thickness control of the large-size spring steel plate are achieved, the thickness machining amount of the steel plate is reduced by four times compared with that of a forging technology, the higher yield is achieved, and the production cost of large-size springs is greatly reduced.

The application relates to a preparation process of a high-density powder metallurgy iron-based alloy, and relates to the technical field of metallurgical materials, in particular to a high-density powder metallurgy iron-based alloy preparation process. The preparation process comprises the following steps: taking copper (2%), nickel (2%), molybdenum (1%), graphite (0.3%) and the rest of iron according to the mass percentage, and making the above raw materials into 800-mesh powders; uniformly mixing the powders; pressing the mixed powders into blanks; sintering the blanks at 1100-1250 DEG C under a protective atmosphere or vacuum condition for 30-120 minutes; and obtaining the iron-based alloy product through shaping. The iron-based alloy material prepared by optimizing the powder granularity (800-1000 mesh), the pressing mode and the sintering is obviously superior to traditional powder metallurgy iron-based materials. The iron-based alloy product has the comprehensive advantages of high density, high strength, good size precision and stable performance, and has a wide industrial application prospect.

The invention discloses an iron-based titanium carbide additive as well as a preparation method and application thereof, and relates to the technical field of alloy materials. The iron-based titanium carbide additive is an iron-based alloy. The specific preparation method comprises the following steps: weighing a titanium source, a carbon source and an iron-based dispersing agent in proportion, and uniformly mixing to obtain mixed powder; rolling the mixed powder into a core-spun yarn or pressing the mixed powder into a cake-shaped material; weighing an iron-based raw material, and heating and smelting the iron-based raw material to form a raw material solution; adding the material rolled into the core-spun yarn or pressed into the cake shape into the raw material solution for reaction to generate an iron-based alloy melt; and the iron-based alloy melt is subjected to forming treatment, and the iron-based titanium carbide additive is obtained. According to the invention, through a synergistic process of'core-spun yarn / block cake + deep addition + in-situ reaction ', the prepared additive contains dispersed TiC particles, the particle size can reach the nanoscale, and the strength, toughness and wear resistance of the steel are remarkably improved.

The invention relates to the technical field of shield tunneling machines, and particularly discloses a shield hobbing cutter ring and a remanufacturing method thereof. According to the method, the iron-based alloy powder serves as a main body, the modified powder is added as an auxiliary, the remanufactured alloy powder is obtained, the alloy deposition layer is formed on the surface of the cutter ring body through the remanufactured alloy powder, and remanufacturing machining of the shield hob cutter ring is completed. Under the synergistic effect of the components of the modified powder, the alloy deposition layer can have good hardness and wear resistance, the defects of iron-based self-fluxing alloy are overcome, the defects of the remanufactured and repaired cutter ring in the tunneling process are reduced, and various extreme service conditions can be fully dealt with.

The invention relates to a wire rod for an 80-grade cord thread and a manufacturing method of the wire rod, and belongs to the field of iron-based alloys. The hot-rolled wire rod comprises the following chemical components in percentage by mass: 0.75%-0.85% of C, 0.10%-0.40% of Si, 0.30%-0.50% of Mn, less than or equal to 0.030% of P, less than or equal to 0.030% of S, 0.03%-0.15% of Cr, 0.03%-0.15% of Ni, 0.03%-0.15% of Cu, 0.01%-0.10% of Mo, less than or equal to 0.01% of N and the balance of Fe and inevitable impurities, Mn + Cr + Cu + Ni + Mo is more than 0.40% and less than 0.70%, Mn / 6 + (Cr + Mo) / 5 + (Cu + Ni) / 15 is more than 0.06% and less than 0.12%, Cr + Cu + Ni + Mo is more than 0.10% and less than 0.25% is more than 0.10% According to the wire rod, electric furnace smelting is achieved on the basis that the high-quality cord thread tensile strength and the low drawing wire breakage rate are guaranteed, the adding proportion of waste steel exceeds 70% of the total loading amount, and the production and manufacturing cost is reduced.

The present invention forms part of the development of new iron-based alloys, particularly a steel with improved mechanical, thermal and physico-chemical (corrosion) properties. The invention relates more specifically to a steel material with a new microstructure, characterized by a triple hierarchical structuring in which appears a network of internal nanometric sub-cells capable of improving the properties and performance of steels.

To provide an Fe-based alloy for melt-solidification-shaping which can give a shaped object having small deformation during shaping, a high processing efficiency in an as-shaped state and a low content of expensive alloy elements when applied to melt-solidification-shaping, and a metal powder having a composition that is equivalent to that of the Fe-based alloy.SOLUTION: An Fe-based alloy for melt-solidification-shaping contains 0.05≤C≤0.25 mass%, 0.01≤Si≤2.0 mass%, 0.05≤Mn≤2.5 mass%, 2.5≤Ni≤9.0 mass%, 0.1≤Cr≤8.0 mass%, and 0.005≤N≤0.200 mass%, with the balance being Fe and inevitable impurities, satisfying 11.5<15C+Mn+0.5Cr+Ni<20. There is also provided a metal powder having an average composition that is equivalent to that of the Fe-based alloy.SELECTED DRAWING: Figure 3

This invention provides a fatigue-resistant high-strength spring steel and its preparation method. By synergistically designing the chemical composition of the iron-based alloy, the low-hydrogen clean molten steel intermediate, the hot rolling controlled cooling, and the quenching-partitioning heat treatment, the steel after stress relief treatment includes tempered martensite and 4-12 vol% retained austenite, and contains nano-precipitates. This results in a fatigue-resistant high-strength spring steel with a tensile strength of 2050-2250 MPa, an elongation after fracture of 8-12%, a reduction of area of ​​30-45%, and a rotational bending fatigue strength of 800-950 MPa. This invention solves the problem of balancing ultra-high strength and long-life fatigue resistance, and the difficulty in achieving both cold-rolling forming processing window and post-stress relief microstructure and dimensional stability. It is suitable for the preparation of high-load spring components.

The invention discloses a method for preparing a high-performance rare earth magnesium-silicon-iron alloy through cooperation of pulsed magnetic field treatment and multi-element microalloying, and belongs to the technical field of metallurgy. The method comprises the following steps: smelting ferrosilicon-based alloy liquid in a submerged arc furnace; the base liquid is thermally loaded into a medium-frequency induction furnace, trace elements such as Ba, Sr, Sb and Bi are added in a cored wire feeding mode, and electromagnetic stirring is conducted to achieve multi-element microalloying; the alloy liquid is heated and then subjected to pulsed magnetic field treatment, the parameters are as follows: the magnetic field intensity is 0.5-3.0 T, the pulse frequency is 5-30 Hz, and the treatment time is 5-20 minutes; then adding magnesium and nitrogen under pressure and stirring; and finally, casting and quickly cooling under the protection of nitrogen. The solidification structure is refined through the pulsed magnetic field, the yield of microelements is increased through core-spun yarn feeding, the magnesium oxide content is reduced through nitrogen protection in the whole process, segregation is restrained through rapid cooling, the magnesium oxide content in the prepared alloy is smaller than or equal to 6% of the magnesium content, the macrosegregation degree is smaller than or equal to 0.3, and the average grain size is smaller than or equal to 50 micrometers. The alloy prepared through the method is good in spheroidizing stability, uniform in structure, low in cost and suitable for production of high-end nodular iron castings.

An interconnector for a solid-oxide electrochemical cell stack of the embodiment includes: a metal base containing an iron-based alloy containing chromium; and a protective film provided on a surface of the metal base. The protective film includes a protective film body containing at least one selected from a spinel oxide and a perovskite oxide, and dispersed phases scattered in the protective film body and containing an oxide of at least one element selected from the group consisting of rare earth elements and zirconium.

The invention relates to the technical field of formaldehyde removal materials, in particular to a formaldehyde removal anode material capable of automatically generating a manganese-series catalyst, which is prepared from an iron-based alloy and no less than 2% of elemental manganese, and a manganese dioxide catalytic film layer can be automatically generated on the anode surface in the electrolysis process. And after being damaged, the film layer can be self-repaired under the condition of continuous electrolysis work or contact with oxygen. In the working process of electrolysis in water, a manganese dioxide catalytic film layer is formed on the surface of the anode, and the film layer has excellent electro-catalytic activity, so that the reaction rate and thoroughness of formaldehyde oxidation can be remarkably improved. Compared with a traditional anode which has no catalytic activity or is fixedly coated with a catalytic layer on the surface, the material can continuously maintain high catalytic efficiency, and it is ensured that formaldehyde is efficiently converted into harmless carbon dioxide and water under low energy consumption.

The application provides a self-catalytic reformer based on a 3D printing technology and a manufacturing method thereof, and the method comprises the following steps: S1, respectively taking nickel-based alloy powder and / or iron-based alloy powder and nickel-aluminum alloy powder, mixing the powders uniformly in a mixing device to obtain printing powder; S2, using three-dimensional drawing software to obtain a shell structure with a reserved cavity; S3, using porous design software to obtain a porous structure, and the porous structure is matched with the reserved cavity of the shell structure; S4, 3D printing the self-catalytic reformer: taking the printing powder in step S1 and adding the powder into a powder supply bin of a 3D printer, then respectively taking the shell structure in step S2 and the porous structure in step S3 and introducing the structures into the 3D printer, and using 3D printing technology to print an integrally formed self-catalytic reformer. The self-catalytic reformer is obtained by the above method. The structure and function are integrated, no additional catalyst is needed, the catalytic efficiency is improved, and the production cost is reduced.

The application discloses a low magnetic permeability amorphous alloy, characterized in that the low magnetic permeability amorphous alloy is formed by segmental magnetic field heat treatment of an iron-based alloy disordered structure strip, and the alloy composition of the iron-based alloy disordered structure strip is Fe-Si-B-M, wherein M is one or more of C, Co, Nb, Mn, Cu and Ni. The application reduces the dislocation dipole density of the alloy, improves the structural disorder, effectively releases the internal stress, and combines the uniform magnetic anisotropy induced by the segmental magnetic field, so as to realize the low magnetic permeability and low loss of the amorphous alloy. The application further discloses a preparation method of the low magnetic permeability amorphous alloy and application of the low magnetic permeability amorphous alloy to a hybrid magnetic circuit distribution transformer.

An apparatus for producing a metallic product, in particular for producing a metallic long product, in particular for producing a metallic bar and / or a metallic wire, in particular a metallic product of an iron-based alloy, the apparatus includes an electric arc furnace for producing a molten metal from a metallic raw material; a continuous caster for producing a billet strand from the molten metal; and a rolling plant for forming the billet strand into the metallic product; wherein the apparatus is set up to reduce a sum of scope 1 CO2 emissions and scope 2 CO2 emissions, in particular the apparatus includes a sum of scope 1 CO2 emissions and scope 2 CO2 emissions of less than or equal to 300 kg / t of the metallic product, preferably less than or equal to 275 kg / t and particularly preferably less than or equal to 250 kg / t.

A gas sensor comprises a sensor element extending axially with electrode pads on its surface at one rear end, metallic connection components that elastically contact the electrode pads, and a separator that holds the metallic connection components. The metallic connection components are made of an iron-based alloy and contain nickel in the range of 9.75 to 10.25 wt%, chromium in the range of 23.00 to 23.90 wt%, manganese in the range of 5.80 to 6.20 wt%, nitrogen in the range of 0.47 to 0.53 wt%, unavoidable impurities, and residual iron. The gas sensor can be manufactured at low cost and exhibits excellent reliability of the electrical connection between the metallic connection components and the sensor element at high temperatures.

The present invention provides a high-strength, high-ductility iron-based alloy containing, by mass%, 0.35 to 0.65% C, 0.1 to 1.0% Si, 0.2 to 2.0% Mn, 0.030% or less P, and 0.030% or less S, with the balance being Fe and unavoidable impurities, having a solidification structure in which the arithmetic mean grain size of the crystals is 10 μm or less, a tensile strength of 1100 MPa or more, an elongation of 13% or more, and satisfying the equation [tensile strength (MPa)] × [elongation (%)] ≥ 16000.

The invention relates to an economical wear-resistant steel ball manufacturing method, and belongs to the technical field of iron-based alloys. The steel ball comprises the following chemical components in percentage by mass: 0.75 to 0.85 percent of C, 0.15 to 0.35 percent of Si, 1.20 to 1.40 percent of Mn, less than or equal to 0.15 percent of P, less than or equal to 0.15 percent of S, 1.20 to 1.40 percent of Cr, less than or equal to 0.3 percent of Ni, less than or equal to 0.3 percent of Cu, less than or equal to 0.05 percent of Mo, less than or equal to 0.06 percent of V, 0.01 to 0.03 percent of Ti, 0.015 to 0.03 percent of Al and 90 to 150PPM of N. The balance is Fe and inevitable impurity elements; molten steel is smelted according to the chemical components, the molten steel is cast into a blank, the casting blank is hot-rolled into round steel, the round steel is taken to be heated to 1100 + / -50 DEG C and rolled into a steel ball, the steel ball is quenched and tempered, and a final steel ball product is obtained, wherein the diameter phi of the steel ball is 130-150 mm, and the average volume hardness is 60-64 HRC.

The invention relates to the field of beryllium smelting, in particular to a method for efficiently removing iron in the melting transformation process of low-grade beryllium concentrate, which comprises the following steps: S1, treating the low-grade beryllium concentrate, and uniformly mixing the low-grade beryllium concentrate with limestone and coke in proportion; s2, pressing and shaping the mixed substances into a mixed ball; s3, putting the mixed ball into a crucible, and smelting; s4, the smelted mixed cluster is a molten-state material, the molten-state material is poured into a mold to be cooled, and the high-activity beryllium-containing glass slag and the iron-based alloy are obtained; and S5, the beryllium-containing glass slag and the iron-based alloy are separated through mechanical crushing. The method has the effect of achieving efficient iron removal in the melting transformation process.

To provide a hot work tool steel powder exhibiting superior thermal conductivity and superior resistance to molding cracking, and a molded article for additive manufacturing that is formed from the powder.SOLUTION: An Fe-based alloy powder comprises, in mass%, C: more than 0.10% to less than 0.45%, Si: less than 0.60%, Mn: less than 5.00%, Cr: less than 2.00%, Ni: less than 8.00%, Mo: less than 2.30%, W: less than 2.00%, V: more than 0.6% to less than 1.50%, and Al: less than 0.10%, with the balance being Fe and inevitable impurities, and satisfying Ni+Mn: less than 8.50%.SELECTED DRAWING: None

The invention relates to a storage unit (1) for liquefied gas and a sealed and insulated tank (71) comprising a loading / unloading opening (10) having an upper cover wall (23), a lower cover wall (22) and an insulation structure (24) located between the lower cover wall (22) and the upper cover wall (23), the pipe (30) and the upper cover wall (23) being made of different types of iron-based alloys and at least one attachment lug (50) extending from the upper cover wall (23) being attached to the lower cover wall (22) in a sealed manner, directly or indirectly.

The nozzle member of at least one embodiment of the present disclosure is a nozzle member included in a variable nozzle mechanism of a variable capacity turbocharger. The nozzle member is composed of an iron-based alloy. In a case where a total value of a carbon content and a nitrogen content of the nozzle member is set as A mass%, and a total value of 0.5 times a tungsten content and a molybdenum content is set as B mass%, a relationship indicated by the following expression is satisfied: 6.6 x A + B ≥ 8.0. A value of the total value B is 1.5 mass% or more.

This application provides a high-entropy alloy-induced carbide precipitation-strengthened iron-based high-temperature wear-resistant coating and its preparation method, relating to the field of high-temperature wear-resistant coating technology. The method includes drying high-entropy alloy powder and iron-based alloy powder; mixing the dried powders; and then using laser cladding equipment to prepare the coating. The material used in this application achieves martensitic transformation strengthening and carbide synergistic strengthening by precisely controlling the precipitation of eutectic carborides during solidification using high-entropy alloys. During solidification, δ-Fe nucleates and grows first. As the liquid phase composition changes to near the eutectic point, Cr and Mo carborides (MC) begin to nucleate and grow. At this point, δ-Fe begins to transform into γ-Fe, which then undergoes a martensitic transformation. After cooling to approximately 700°C, the phase transformation nearly stops, and C only diffuses short-range to form M6(CB) type carborides, promoting the synergistic strengthening mechanism of the material and balancing strength and toughness.

The present invention relates to a method of manufacturing a high strength and high thermal conductivity iron-based alloy additive manufactured body using a laser-powder bed melt object, the method comprising: using an iron-based alloy powder having an Ms point above 220 DEG C, a C content of 0.40 mass% or less, a Cr content of 7 mass% or less, an Fe content of 90 mass% or more; when the energy density per unit area EA is defined as EA = P / (v * sigma), the laser is manufactured at a laser power P (W), a scanning speed v (mm / s), and a laser spot diameter sigma (mm) under the condition that the energy density per unit area EA is 3 J / mm2 or more.

The present invention addresses the problem of providing a build-up layer that can have improved corrosion resistance and wear resistance, and provides an Fe-based alloy build-up layer which contains C, Si, Mn, Cr, Mo, and V, with the remainder comprising Fe and unavoidable impurities, wherein: the contents of C, Si, Mn, Cr, Mo, and V respectively satisfy 1.60 mass% ≤ C ≤ 3.50 mass%, 0.20 mass% ≤ Si ≤ 1.50 mass%, 0.20 mass% ≤ Mn ≤ 1.50 mass%, 14.0 mass% ≤ Cr ≤ 26.0 mass%, 0.2 mass% ≤ Mo ≤ 2.0 mass%, and 4.0 mass% ≤ V ≤ 8.0 mass%; in a cross-section of the Fe-based alloy build-up layer, the ratio of the total area of fine granular carbides having a diameter of 5 µm or less to the area of the observation region is 0.50% to 4.00% inclusive; and the amount of Cr solid solution contained in the primary crystal of the Fe-based alloy build-up layer is 5 mass% or more.