660 results about "Pearlite" patented technology

The invention relates to a high-strength complex-phase hot-rolled wire rod for a 1960MPa-grade stranded wire and a manufacturing method of the high-strength complex-phase hot-rolled wire rod. After high-carbon components containing trace B are designed, rolled and spun into a wire rod, online molten salt rapid quenching treatment is carried out, and the wire rod is firstly subjected to front-section molten salt treatment, so that the wire rod is cooled at the cooling speed of greater than or equal to 36 DEG C / s and enters a bainite and pearlite mixed phase region from an austenite state; the method comprises the following steps: quenching a steel wire rod to form a structure mainly comprising quenched bainite and a sorbite structure, carrying out rear-section molten salt treatment on the steel wire rod, increasing the molten salt temperature, promoting isothermal tempering of the quenched bainite and the sorbite structure, and carrying out roller way slow cooling to prepare the hot-rolled steel wire rod of which the microscopic structure comprises a complex-phase structure consisting of tempered sorbite, tempered bainite and ferrite, the composition system can be simplified, the strength and plasticity matching and rapid production of the wire rod are considered, the tensile strength is 1330-1380 MPa, the percentage reduction of area is 35%-40%, and the wire breaking risk in the wire drawing and twisting process of the stranded wire steel can be reduced.

The invention relates to a high-strength complex-phase hot-rolled wire rod for a 2060MPa-grade stranded wire and a manufacturing method of the high-strength complex-phase hot-rolled wire rod. After high-carbon chemical components containing trace V are designed, rolled and spun into a wire rod, the wire rod is cooled at a cooling speed of more than or equal to 33 DEG C / s through on-line molten salt semi-quenching treatment, enters a bainite and pearlite mixed phase region from an austenite state, and is subjected to hot rolling and hot rolling at a cooling speed of more than or equal to 33 DEG C / s; the method comprises the following steps: quenching bainite and a sorbite structure to form a structure mainly comprising the quenched bainite and the sorbite structure, then carrying out isothermal tempering, and finally carrying out roller way slow cooling to prepare the hot-rolled wire rod of which the microscopic structure comprises a complex-phase structure consisting of tempered sorbite and tempered bainite, so that a component system can be simplified, the material cost can be reduced, network carbides can be effectively controlled, and meanwhile, the complex-phase structure can be regulated and controlled; the high strength and plasticity of the wire rod are matched, the tensile strength is 1390-1440 MPa, the percentage reduction of area is 32%-37%, and the steel wire rod is used for manufacturing 2060 MPa grade stranded wires and other application fields and is beneficial to downstream wire drawing and twisting processing.

The invention relates to a high-strength complex-phase hot-rolled wire rod for a 2230 MPa grade stranded wire and a manufacturing method of the high-strength complex-phase hot-rolled wire rod. After a Nb-containing high-carbon component is used for rolling and spinning at a spinning temperature to form a wire rod, online molten salt mixing quenching isothermal treatment is carried out, so that the wire rod is firstly subjected to front-section molten salt treatment and is cooled at a cooling speed of more than or equal to 35 DEG C / s, and enters a bainite and pearlite mixed phase region from an austenite state; the method comprises the following steps: firstly, carrying out heat treatment on austenite to promote part of austenite to be converted into bainite and sorbite, then carrying out later-section molten salt treatment, increasing the molten salt temperature, promoting unconverted retained austenite to be decomposed and converted into sorbite, carrying out isothermal tempering, and finally, carrying out roller way slow cooling, so as to prepare the hot-rolled wire rod of which the microscopic structure comprises a complex-phase structure consisting of tempered bainite and tempered sorbite, the drawing and hardening capacity can be improved, the production efficiency is considered, the tensile strength is 1522-1572 MPa, and the percentage reduction of area is 29%-34%, so that off-line heat treatment is avoided, and the wire breaking risk and cost of stranded wire manufacturing are reduced.

The cold heading wire rod comprises the following components in percentage by mass: 0.20%-0.26% of C, less than or equal to 0.35% of Si, 1.2%-1.6% of Mn, less than or equal to 0.02% of P, less than or equal to 0.005% of S, 0.04%-0.14% of V, 0.02%-0.10% of Nb, less than or equal to 0.2% of Cr, less than or equal to 0.1% of Ni, 0.02%-0.06% of Al and the balance of Fe and inevitable impurities, the V + Nb is greater than or equal to 0.09%, the C / 4 + Si + Mn / 2 + Cr / 2 + 2Ni is greater than or equal to 1.1% and less than or equal to 1.3%, the F + P is greater than or equal to 95%, the F grain size is greater than or equal to grade 12, the longitudinal pearlite strip The steel plate prepared by the method does not crack at 1 / 5 of a hot rolling state, can meet the requirements of a user on strength and plasticity of cold heading forming after 5-50% of cold drawing deformation, and can meet the requirements of a 10.9-grade high-strength fastener on fatigue and delayed fracture resistance at the same time.

The invention relates to a high-strength complex-phase hot-rolled wire rod for a 2200MPa-grade stranded wire and a manufacturing method of the high-strength complex-phase hot-rolled wire rod, and the manufacturing method comprises the following steps: rolling and spinning to form a wire rod by adopting a high-hardenability component design, and then carrying out online molten salt mixed phase region quenching isothermal treatment, so that the wire rod is firstly subjected to front-section molten salt treatment and enters a bainite and pearlite phase region from an austenite state; the method comprises the following steps: carrying out high-temperature treatment on austenite to promote part of austenite to be converted into bainite and sorbite, carrying out later-section molten salt treatment, increasing the molten salt temperature, reducing the molten salt circulation amount, promoting unconverted retained austenite to be decomposed and converted into bainite and sorbite, carrying out isothermal tempering, and finally carrying out slow cooling through a roller way, the hot-rolled wire rod with a microscopic structure comprising a complex phase structure composed of tempered bainite and tempered sorbite is prepared, the material cost can be reduced, the complex phase structure and the structure toughness can be regulated and controlled on line, the tensile strength is 1505-1555 MPa, the percentage reduction of area is 32%-37%, efficiency and energy consumption are both considered, off-line heat treatment is avoided, and high-efficiency production of stranded wires is promoted.

The invention relates to the technical field of manufacturing of engineering machinery parts, and discloses an engineering machinery driving wheel made of a medium carbon alloy cast steel material. The invention also discloses a preparation process of the engineering machinery driving wheel material, which comprises the following steps: S1, casting treatment: melting the medium carbon alloy steel material, and casting into a driving wheel blank; s2, normalizing heat treatment: carrying out normalizing heat treatment on the driving wheel blank; s3, rough machining treatment; s4, quenching treatment: carrying out induction quenching treatment; and S5, finish machining treatment. The synergistic effect of alloy elements in a medium carbon alloy cast steel material is combined with an optimized air cooling process, so that the cast steel is normalized to obtain a uniform structure which mainly contains superfine pearlite and contains extremely little ferrite, the matrix hardness is stable, and the requirement of a high-performance driving wheel is completely met; after the process route is improved, tempering and shot blasting and flaw detection procedures after tempering are canceled; the technological process is greatly shortened, material turnover is reduced, and the production efficiency is improved.

The invention relates to a high-strength complex-phase hot-rolled wire rod for a 2260MPa-grade stranded wire and a manufacturing method of the high-strength complex-phase hot-rolled wire rod, after the high-carbon component design of C-Si-Mn-Cr-V-Nb-V is rolled and spun into a wire rod, the wire rod is subjected to online molten salt mixed quenching isothermal treatment, so that the wire rod is subjected to front-section molten salt treatment to be quickly cooled, enters a bainite and pearlite mixed phase region from an austenite state, and is subjected to hot rolling and hot rolling to form the high-strength complex-phase hot-rolled wire rod. The method comprises the following steps: carrying out first-stage molten salt treatment on austenite to promote transformation of part of austenite to bainite and sorbite, then carrying out later-stage molten salt treatment to increase the molten salt temperature, promoting decomposition and transformation of untransformed retained austenite into sorbite, carrying out isothermal tempering, and finally carrying out slow cooling through a roller way, a hot-rolled wire rod with a microscopic structure comprising a complex-phase structure composed of tempered bainite, tempered sorbite and ferrite is manufactured, the tensile strength is 1547-1597 MPa, and the percentage reduction of area is 27%-32%, so that when a high-strength stranded wire is manufactured, off-line heat treatment is not needed, the drawing pass number is reduced, and the wire breaking risk is reduced.

An embodiment of the present invention provides a steel material, for a pressure vessel, comprising, in weight %, 0.06-0.25% of carbon (C), 0.05-0.50% of silicon (Si), 1.0-2.0% of manganese (Mn), 0.005-0.40% of aluminum (Al), 0.010% or less of phosphorus (P), 0.0010% or less of sulfur (S), 0.001-0.03% of niobium (Nb), 0.001-0.03% of vanadium (V), 0.001-0.03% of titanium (Ti), 0.01-0.20% of chromium (Cr), 0.05-0.15% of molybdenum (Mo), 0.01-0.50% of copper (Cu), 0.05-0.50% of nickel (Ni), 0.0005-0.0050% of magnesium (Mg), 0.0005-0.0050% of calcium (Ca), 0.0020% or less of oxygen (O), and the remainder being Fe and other unavoidable impurities. A microstructure comprises in terms of area fraction 30% or less of pearlite and the remainder being ferrite. A non-metallic inclusion contains Mg—Al—Ca—O composite oxide.

The invention relates to the field of screw forming, and discloses a screw cold heading forming process which is characterized by comprising the following steps: step 1, wire preparation and surface pretreatment: based on the requirement of screw forming on the surface quality of raw materials, a metal wire is treated by adopting a mechanical wiredrawing and chemical phosphating and saponifying composite process, and the surface of the metal wire is treated; surface oxide skin is removed, a lubricating film layer is formed, and the forming flowability and the service life of the die in the subsequent cold heading process are effectively improved. A raw material is subjected to spheroidizing annealing treatment in a continuous spheroidizing annealing furnace, internal pearlite is converted into spherical cementite, the ductility and deformation uniformity of the material are improved, then a continuous wire drawing machine is adopted for multi-stage drawing diameter reduction, a three-stage chemical phosphating-saponification treatment process is matched, a low-friction and high-adhesion lubricating film layer is formed, and the service life of the lubricating film layer is prolonged. And a stable material basis and a lubricating environment are provided for the subsequent cold heading process, so that the problems that the friction resistance generated in the forming process of a screw material is large, and a mold is quickly worn are solved.

The invention discloses medium-carbon round steel for cold extrusion, which contains Fe and inevitable impurities, and further contains the following chemical elements in percentage by mass: 0.36 to 0.43 percent of C, 0.1 to 0.4 percent of Si, 0.6 to 1 percent of Mn, 0.6 to 1 percent of Cr, 0.2 to 0.4 percent of Mo, 1.4 to 1.7 percent of Ni, 0.02 to 0.04 percent of Al, 0.008 to 0.015 percent of N and the balance of Fe. And after annealing, the microstructure is flaky pearlite and spherical pearlite. Correspondingly, the invention also discloses a manufacturing method of the medium-carbon round steel for cold extrusion, which comprises the following steps: (1) smelting and casting; (2) heating; (3) forging or rolling; (4) stepped annealing; and (5) surface treatment.

Provided is a steel sheet characterized by having a prescribed chemical composition and in that: the metal structure thereof contains, in terms of area%, 10-40% of ferrite, 60-90% of martensite, 0-10% of bainite, and a total of 0-5% of at least one among pearlite and retained austenite; and when a 150 μm × 150 μm region at a position at 1 / 4 of the sheet thickness in a cross section perpendicular to the sheet surface is equally divided into nine regions, the number density of ferrite in each of the divided regions is calculated, and the average value thereof is indicated by Nαm, the difference in the number density of ferrite between divided regions adjacent to each other in the sheet thickness direction is Nαm × 0.60 or less in all cases. Also provided are a component including the steel sheet, and a method for manufacturing the steel sheet.

The invention relates to large-thickness high-homogeneity polar region ship low-temperature steel and a preparation method thereof. The steel plate comprises the following chemical components in percentage by weight: 0.06%-0.12% of C, 0.15%-0.35% of Si, 1.10%-1.40% of Mn, less than or equal to 0.008% of P, less than or equal to 0.008% of S, 0.020%-0.050% of Nb, 0.020%-0.040% of Al, 0.010%-0.020% of Ti, 0.04%-0.08% of residual element Mo and the balance of Fe and inevitable impurity elements. The carbon equivalent CEV is less than or equal to 0.38%, and the cold crack sensitivity index Pcm is less than or equal to 0.20%. The manufacturing process of the steel plate comprises the steps of KR, BOF smelting, LF, RH, slab continuous casting, slab slow cooling, heating, rolling, steel plate pile slow cooling and heat treatment, the matrix structure of the obtained steel plate is a uniform and fine ferrite and tempered pearlite mixed structure, and the grain size ranges from 8 micrometers to 15 micrometers. The yield strength of the transverse tensile property at the 1 / 4 position of the steel plate ranges from 376 MPa to 392 MPa, the tensile strength ranges from 528 MPa to 553 MPa, the ductility is larger than or equal to 27.0%, the yield strength of the transverse tensile property at the 1 / 2 position ranges from 359 MPa to 375 MPa, the tensile strength ranges from 524 MPa to 537 MPa, the ductility is larger than or equal to 26.5%, and the steel plate is excellent in performance, excellent in whole plate uniformity, good in plate shape and easy to weld.

The invention belongs to the technical field of rolling, and particularly relates to an anti-decarburization and anti-brittle failure controlled cooling process for a high-silicon-chromium alloy tool steel wire rod. Aiming at the dilemma that the hot-rolled wire rod which contains more than 2.0% of Si, more than 1.1% of Cr, Mo, V and other alloy elements not only meets the decarburization requirement of a product, but also does not have brittle failure of the wire rod, the method comprises the following steps: firstly, determining the cover entering temperature of the hot-rolled wire rod, the cooling speed of the wire rod before the hot-rolled wire rod enters the cover and other key process parameters; and then the method is realized by adjusting the speed of a roller way, the number of opened heat preservation covers after spinning, a fan Jinling device, the air volume of a fan, the spinning temperature and the like, so that the hot rolling structure of the wire rod is a pearlite structure which is not easy to brittle, and meanwhile, the requirement that the decarburization of a product does not exceed 0.55 D (D is the diameter of the wire rod) is met.

The invention provides a heat treatment method for a wind power gear forge piece. The heat treatment method comprises the following steps that 1, after-forging waste heat temperature equalization is carried out; 2, segmented forced controlled cooling is carried out till the forge piece reaches a furnace entering window, and forced cooling is carried out on the forge piece; at least three temperature measuring points are arranged on the forge piece; 3, isothermal normalizing for the first time, wherein the forge piece is placed in an isothermal furnace; 4, low-temperature reaustenitizing is conducted, specifically, the forge piece subjected to the first isothermal normalizing is heated to 860-910 DEG C, heat preservation is conducted, and the forge piece is reaustenitized; 5, secondary isothermal normalizing is conducted, specifically, the forged piece obtained after austenitizing is cooled to 645-670 DEG C in a controlled cooling mode, and isothermal heat preservation is conducted; the forge piece is heated to 380-450 DEG C, heat preservation is conducted, then the forge piece is cooled to 200 DEG C or below along with a furnace, and the forge piece is taken out of the furnace for air cooling. According to the method, a uniform and refined ferrite and pearlite structure is obtained in the core of the large-section forge piece, the hardness is stabilized within the range of 165-185 HBW, and the subsequent carburizing and quenching distortion sensitivity is reduced.

The invention discloses a cast iron material suitable for a large-size thin-wall high-strength wind power hub and a preparation method and application of the cast iron material, and belongs to the technical field of materials and casting technologys.By optimizing alloy component design and combining the synergistic effect of trace rare metal elements of barium (Ba), antimony (Sb) and bismuth (Bi) and rare earth elements (RE), the high-strength wind power hub is obtained; and by adding a three-phase SiC / SiO2 / TiC nano-particle reinforced phase, pearlite formation is inhibited, graphite nodules are refined, the spheroidization rate is larger than or equal to 95%, and the ferrite content is larger than or equal to 90%. And by adding a nano-particle reinforced phase and controlling the proportion of alloy elements such as Ni < = 0.8%, the corrosion resistance of the material is further improved. The ductile cast iron material with high spheroidization rate, excellent mechanical property, low-temperature impact resistance and corrosion resistance is prepared by using the low-temperature-resistant and high-strength casting process and the intelligent temperature-controlled and cold-controlled casting process, and the requirements of light weight, high strength, corrosion resistance and high reliability of 18MW-grade offshore wind power hubs are met.

The invention provides a full-pearlite steel rail and a production method and application thereof. According to the invention, by controlling the content of elements in the steel rail, especially the C, Mn and Cr elements and the content ratio thereof, and optimizing the online heat treatment process of the steel rail, the steel rail with a full pearlitic structure is obtained under the condition that other production processes of the steel rail are not limited, and the tensile strength of the steel rail is greater than or equal to 1100MPa, the percentage elongation after fracture is greater than or equal to 10%, and the surface hardness is greater than or equal to 330HB. Meanwhile, the production method of the all-pearlite steel rail is simple and easy to operate, and large-scale application and popularization of the all-pearlite steel rail in lines such as high-speed railways and passenger and freight mixed transportation railways are facilitated.

This hot-rolled steel sheet has a predetermined chemical composition, in a microstructure at a depth position of 1 / 4 from a surface in a sheet thickness direction, in terms of area %, residual austenite is less than 3.0%, ferrite is 15.0% or more and less than 60.0%, and pearlite is less than 5.0%, an E value is 10.7 or more, an I value is 1.020 or more, a CS value is −8.0×105 to 8.0×105, a standard deviation of Mn concentrations is 0.60 mass % or less, a solute Cr concentration in an outermost layer region is 0.10 mass % or more, a number density of Cr oxides having a sphere equivalent radius of 0.1 μm or more at the surface is 1.0×104 pieces / cm2 or less.

The invention belongs to the field of steel production, and relates to a method for producing 460MPa-grade hot-rolled thin strip steel based on double-roller cast rolling. Molten steel is subjected to double-roller continuous casting and sub-rapid solidification to form a cast strip, is subjected to one-pass hot rolling to form a thin strip, is subjected to aerial fog cooling to 530-610 DEG C and is coiled, the coiled thin strip is placed in a cover type annealing furnace to be heated and subjected to heat preservation for 1-2 days, and a hot-rolled thin strip finished product is obtained after finishing. According to the method, a medium-carbon low-manganese low-silicon microalloy-element-free component system is adopted, the high-strength hot-rolled thin strip with the low yield ratio is produced through a short-process double-roller cast rolling production line, and the production energy consumption and the alloy cost are remarkably reduced. A bainite, ferrite and pearlite composite structure with the large grain size is obtained by combining the precise control aerial fog cooling process with the online waste heat annealing process design, the yield ratio is low in performance, the low-temperature toughness is good, and the strength uniformity is good. And the isotropy of the finished product is obviously superior to that of a traditional hot-rolled low-alloy product, and the finished product is suitable for producing thin-specification components through cold bending and punch forming.

The invention discloses a method for refining and homogenizing crystal grains of a 9%-12% Cr steel thick-wall large forge piece, and belongs to the field of ferrous metallurgy. According to the method, the large forge piece is heated to be close to the critical point of the complete austenitizing temperature in a stepped mode, the large forge piece is subjected to heat treatment by regulating and controlling dispersive precipitation of carbides in an initial structure and uniform nucleation of austenite and / or introducing a small amount of undissolved ferrite, residual precipitated phases and multi-phase interfaces and controlling the cooling speed; nucleation particles of pearlite transformation in the vibration heat preservation process are remarkably increased, uniform distribution of granular pearlite in the supercooled austenite is promoted, structural inheritance is cut off and eliminated, and the purpose of grain refining and homogenizing after performance heat treatment is achieved. According to the method, the grains of the thick-wall large forge piece are refined to 5 grades or above, the cross section grain size difference is within 2 grades, a series of problems that in the production process, grass waves exist in ultrasonic flaw detection, the grain size is unqualified, and the low-temperature impact toughness does not reach the standard can be solved, the product percent of pass and the production efficiency are remarkably improved, and meanwhile the production energy consumption is reduced.

The invention discloses ultra-fine grain high-strength steel for a steel cord with excellent heat resistance and a production method thereof, the steel for the steel cord comprises the following main chemical components in percentage by weight: 0.86%-0.94% of C, 0.25%-0.45% of Mn, 0.30%-0.40% of Cr, 0.32%-0.45% of Si, 0.025%-0.040% of V and 0.0005%-0.0009% of B, wherein X is more than or equal to 0.80 and less than or equal to 1.20 and is equal to Mn / Cr; 0.32 < = Y = 10 * V + 100 * B < = 0.45; the sorbite rate of the steel for the steel cord reaches 95% or above, pearlite clusters are small, sorbite lamellar spacing is small, meanwhile, a sorbite structure is distributed in a multi-orientation mode, and a steel wire made of the steel for the steel cord is good in torsion fracture, high in strength and toughness and excellent in heat resistance; the production process is stable and reliable, and is suitable for large-scale industrial production.

The invention relates to the technical field of cast iron alloys, in particular to a preparation method of high-carbon-equivalent gray cast iron, which comprises the following steps: taking scrap steel as a main material, taking scrap castings, silicon carbide and a carburant as auxiliary materials, and smelting according to a determined raw material ratio and a determined carbon equivalent value range; sampling smelted molten iron to obtain a first cooling curve of the molten iron, extracting characteristic points, performing thermal analysis to determine the metallurgical state of the molten iron, and adjusting the content of pre-inoculated silicon carbide or analyzing the possibility of over-inoculation; pre-inoculation is conducted on the smelted molten iron, the smelted molten iron is secondarily sampled to obtain a second cooling curve of the molten iron, feature points are extracted, the pearlite form is determined, and the sensitivity index of the smelted molten iron to inoculation is calculated according to the change condition of the feature points of the first cooling curve and the second cooling curve. Through pre-inoculation adjustment and tapping inoculation and pouring inoculation, the problems that graphite is thick and large and the performance is reduced easily due to high carbon equivalent are solved.

The invention relates to gray cast iron and a smelting method thereof, in particular to high-strength gray cast iron and a smelting method thereof. According to the high-strength gray cast iron and the smelting method thereof, the defect that in the prior art, alloying is adopted for improving the strength of the gray cast iron, and consequently the texture of the gray cast iron is poor is overcome, the tensile strength of an attached casting test bar of the high-strength gray cast iron is larger than 300 MPa, and the hardness is larger than 190 HB; the metallographic structure of the high-strength gray cast iron in an as-cast state can achieve more than 98% of pearlite, less than 1% of cementite and more than 90% of A-type graphite, and the strength and the metallographic structure of the alloyed gray cast iron are effectively improved.

This invention relates to a vermicular cast iron alloy with high mechanical strength and thermal conductivity requirements to replace the conventional gray and vermicular cast irons and introduces a manufacturing process for high mechanical strength and thermal conductivity vermicular cast iron alloy and internal combustion engine parts produced from said alloy. The alloy includes carbon, manganese, tin, copper, molybdenum, silicon, magnesium, rare earths, chromium, titanium, niobium, vanadium, tungsten, phosphorus, sulfur, aluminum, and nickel. The alloy has a graphite microstructure consisting of up to 70% of vermicular particles and up to 30% of nodular particles in area, with a matrix in area up to 80% pearlitic and up to 20% ferritic, with presence of segregating carbides of up to 1%.

The invention relates to a chromium-molybdenum steel spheroidizing rating method based on pearlite feature extraction. The method can effectively improve the detection precision and detection efficiency of chromium-molybdenum steel metallographic inspection work. According to the technical scheme, the method comprises the steps that preprocessing and local self-adaptive contrast enhancement algorithm processing are carried out on chromium-molybdenum steel to obtain an image A; a deep learning network is input to obtain a mask result O, a mask segmentation pixel coverage rate R is calculated, if R is smaller than a mask segmentation pixel coverage rate threshold value T, nodulizing is performed at the fifth level, and otherwise, preliminary rating is performed as 1-level nodulizing, 2-level nodulizing, 3-level nodulizing and 4-level nodulizing; carrying out intersection operation on the image A and the mask result O to obtain an image K, carrying out gray processing to obtain a gray image G, calculating an accumulated probability histogram P, calculating a gray entropy mu and an inter-class variance sigma 2, determining a gray segmentation threshold Tg, and carrying out segmentation to obtain an image E; and calculating the gray distribution probability H in each pearlite feature region F in the image E, taking the probability of the pixel point with the gray value of [0, 10] as a spheroidizing grade, and calculating a spheroidizing grade index to obtain a pearlite spheroidizing grade result.

The invention relates to the technical field of steel structure grain size analysis, in particular to a microscopic image segmentation result-based steel structure grain size analysis method, which comprises the following steps of: performing format conversion and size unification on a segmentation result of a deep learning segmentation model to generate a complete mask, and performing mask optimization on the complete mask; and generating a visual distribution diagram based on the distribution states of the ferrite masks and the pearlite masks in the complete masks, performing superposition and proportional scale labeling on the original microscopic images, and quantifying the distribution characteristics of the ferrite and the pearlite by combining a uniformity index and a spatial correlation index. According to the method, the ferrite and the pearlite in the microscopic image are accurately segmented through the deep learning segmentation model, the visual distribution diagram is generated on the basis, and quantitative analysis is performed on the tissue distribution in combination with the uniformity index and the spatial correlation index, so that quantitative and objective tissue structure characterization can be realized.

The invention discloses nodular cast iron and a heat treatment method and application, and belongs to the technical field of nodular cast iron. The nodular cast iron is prepared from, by mass, 3.4%-3.8% of C, 2.0%-3.0% of Si, smaller than or equal to 0.6% of Mn, 0.03%-0.06% of Mg, smaller than or equal to 0.15% of Mo, larger than or equal to 0.2% and smaller than or equal to 1% of Cu and Ni, smaller than or equal to 0.02% of rare earth Re and the balance Fe and inevitable impurities. The nodular cast iron is high in pearlite content and smaller in lamellar spacing, the fatigue strength, the tensile strength and the yield strength can be remarkably improved, meanwhile, the nodular cast iron has the advantage of being low in cost, and a planet carrier prepared from the nodular cast iron material can remarkably improve the service reliability of a wind power gear box and reduce the full-life-cycle maintenance cost.

The invention discloses steel for a 420 MPa grade arctic circle oil and gas exploitation platform and a preparation method of the steel. The steel plate comprises the following chemical components in percentage by weight: 0.06%-0.12% of C, 0.15%-0.35% of Si, 1.00%-1.60% of Mn, less than or equal to 0.008% of P, less than or equal to 0.008% of S, 0.025%-0.060% of Nb, 0.030%-0.080% of V, 0.020%-0.040% of Al, 0.010%-0.020% of Ti, 0.20%-0.60% of Ni, 0.10%-0.30% of Cr, less than or equal to 0.0040% of N and the balance of Fe and inevitable impurity elements. The carbon equivalent CEV is less than or equal to 0.42%, and the cold crack sensitivity index Pcm is less than or equal to 0.20%. The manufacturing process of the steel plate comprises the steps of KR, electric furnace smelting, LF, VD, casting, slab slow cooling, heating, rolling, steel plate pile slow cooling, heat treatment and the like. The matrix structure of the obtained steel plate is a uniform and fine ferrite and tempered pearlite mixed structure, and the grain size ranges from 6 micrometers to 15 micrometers. The steel plate has excellent low-temperature impact toughness, lamellar tearing resistance, fracture resistance and low-temperature strain aging resistance, is easy to weld, and can meet the extremely cold service environment of the arctic circle.

This hot-rolled steel sheet has a desired chemical composition, in a microstructure at a position of ¼ from a surface in a sheet thickness direction, in terms of area %, residual austenite is less than 3.0%, ferrite is 15.0% or more and less than 60.0%, and pearlite is less than 5.0%, an E value is 10.7 or more, an I value is 1.020 or more, a CS value is −8.0×105 to 8.0×105, a standard deviation of Mn concentrations is 0.60 mass % or less, at the surface, an area ratio of a region where a Ni concentration is 0.2 mass % or more is 10.0% or more, an area ratio of a region where an O concentration is 3.0 mass % or more is 3.0% to 50.0%, and a maximum value of sphere equivalent diameters of oxides is 5.00 μm or less, and a tensile strength is 980 MPa or more.

The invention discloses low-temperature nodular cast iron for wind power castings and a preparation method thereof, and belongs to the technical field of nodular cast iron materials. The nodular cast iron is prepared from, by mass, 3.2%-3.6% of C, 2.0%-2.5% of Si, 0.1%-0.2% of Cu, smaller than or equal to 0.3% of Mn, smaller than or equal to 0.03% of P, smaller than or equal to 0.015% of S, 0.03%-0.05% of Mg, 0.08%-0.15% of a nano additive and the balance Fe and inevitable impurities. The material matrix is mainly made of ferrite, the pearlite content is low, graphite nodules are uniformly distributed and regular in shape, and the comprehensive mechanical properties are as follows: the tensile strength is greater than or equal to 500 MPa (QT400-18AL is required to be greater than or equal to 360 MPa); the yield strength is greater than or equal to 350 MPa (the standard requirement is greater than or equal to 220 MPa); and the ductility is not less than 20% (the standard requirement is not less than 12%).

The invention relates to the technical field of cold heading steel wire rod production, in particular to an annealing-free carbon cold heading steel wire rod and a production method thereof. The wire rod comprises the following chemical components in percentage by weight: 0.34%-0.36% of C, less than or equal to 0.05% of Si, 0.70%-0.90% of Mn, less than or equal to 0.010% of P, less than or equal to 0.010% of S, 0.02%-0.04% of Al, 0.015%-0.040% of Ti, less than or equal to 0.0050% of N and the balance of Fe and inevitable impurities. The production method specifically comprises the following steps: 1) heating a steel billet; the method comprises the steps of (1) rolling and spinning, (2) steel wire rod size control, (4) steel wire rod cooling, (5) steel wire rod cooling, (6) steel wire rod cooling, (7) steel wire rod cooling, (7) steel wire rod cooling, (7) steel wire rod cooling, (7) steel wire rod cooling, (7) steel wire rod cooling, (8) steel wire rod cooling, (7) steel wire rod cooling, (8) steel wire rod cooling, (7) steel wire rod cooling, (8) steel wire rod cooling, (8) steel wire rod cooling and (8) steel wire rod cooling, (8) steel wire rod cooling, (8) steel wire rod cooling, (8) steel wire rod cooling, (8) steel wire rod cooling, (8) steel wire rod cooling, (8) steel wire rod cooling, (