3883 results about "Tempering" patented technology

The invention relates to a high-strength complex-phase hot-rolled wire rod for a 2500MPa-grade bridge cable and a manufacturing method of the high-strength complex-phase hot-rolled wire rod, after the high-carbon component of Nb-V-Mo is rolled and spun into a wire rod, the wire rod is subjected to online molten salt tail end quenching toughening treatment, so that the wire rod passes through front-section molten salt and is cooled at a cooling speed of greater than or equal to 38 DEG C / s, a part of austenite structure is transformed into quenched martensite, and a part of austenite structure is transformed into quenched martensite; the method comprises the following steps of: heating to a sorbite phase region temperature through a rear-section molten salt, controlling unconverted austenite to be converted into sorbite, performing isothermal tempering, controlling precipitation and growth of carbides, and finally performing slow cooling through a roller way to prepare a hot-rolled wire rod of which a microscopic structure comprises a complex-phase structure consisting of tempered martensite and tempered sorbite, wherein the tensile strength of the hot-rolled wire rod is 1710-1750MPa; the production method has the advantages that the material cost is controlled, the production efficiency is improved, and the production method is suitable for 2500MPa bridge cable production and is beneficial to reducing the risk of wire breakage in downstream cold drawing and subsequent processing processes.

The invention relates to the technical field of metal forge piece machining, in particular to an irregular metal forge piece heat treatment method and system.The irregular metal forge piece heat treatment method comprises the steps that firstly, temperature compensation partitions are divided according to geometrical characteristics, and stepped preheating is implemented to establish a uniform basic temperature field; then, the heat preservation time of each subarea is independently regulated and controlled in the austenitizing stage, and sufficient transformation of a thick-wall area structure and control over the grain size of a thin-wall area are both considered; in the quenching process, partition strength adjustment is carried out based on a preset cooling map, and cooling parameters are dynamically optimized through real-time feedback; and finally, according to the residual stress distribution, carrying out partition stepped tempering. The heating and cooling uniformity is remarkably improved through partition dynamic temperature management, and the structure difference and thermal stress concentration caused by section sudden change are effectively inhibited; the microstructure is ensured to be uniform and stable through austenitizing control; the hardenability and the deformation resistance are balanced through a differential cooling strategy; and directional reduction of residual stress is achieved through an intelligent tempering mechanism, and the cracking risk is greatly reduced while the comprehensive mechanical property is improved.

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 2100MPa bridge cable 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 C-Si-Mn-Cr-Mo chemical components into a wire rod, and carrying out online molten salt tail end quenching isothermal treatment, so that the wire rod firstly passes through front-section molten salt and is cooled at a cooling speed of more than or equal to 35 DEG C / s to enter a sorbite phase region from an austenite state; the method comprises the following steps of: controlling part of austenite to be converted into sorbite, cooling to a bainite phase through rear-section molten salt, carrying out end quenching, controlling bainite phase change, carrying out isothermal tempering to remove stress, and finally carrying out roller way slow cooling to prepare a complex-phase structure comprising tempered sorbite and tempered bainite, so that abnormal structures of network carbides and martensite can be effectively controlled; the high-strength composite phase structure control and plasticity matching are achieved, the tensile strength is 1530-1560 MPa, the percentage reduction of area is 30%-35%, and the method is suitable for manufacturing 2100 MPa-grade ultrahigh-strength bridge cables with large drawing amount and beneficial to reducing the risk of wire breakage.

The invention relates to a hot-rolled wire rod for a 1960MPa-grade bridge cable and a manufacturing method of the hot-rolled wire rod, after a C-Si-Mn-Cr hypereutectoid component is rolled and spun into a wire rod, the wire rod is subjected to online molten salt strong isothermal treatment, so that the wire rod firstly passes through front-section molten salt and is cooled at a cooling speed of more than or equal to 36 DEG C / s, and enters a sorbite phase region from an austenite state to promote transformation of part of austenite to sorbite; the method comprises the following steps: carrying out high-temperature heat treatment on a steel wire rod, then carrying out rear-section molten salt heating isothermal treatment to promote pearlite phase change and isothermal tempering, and finally carrying out roller way slow cooling to prepare a mixed structure with a microscopic structure mainly comprising tempered sorbite and tempered pearlite and the balance of ferrite and quasi-spheroidized carbide, so that a component system can be simplified, the structure of the steel wire rod is regulated to be uniform, and the service life of the steel wire rod is prolonged. The tensile strength is 1360-1410 MPa, the percentage reduction of area is 45%-50%, the requirement for the strength grade of a 1960 MPa bridge cable is met, and meanwhile the risks of wire breakage and unqualified torsion of manufactured wires are reduced.

The invention relates to a hot-rolled wire rod for a 2060MPa-grade stranded wire and a manufacturing method of the hot-rolled wire rod. Mn-Cr high-carbon chemical component design and rolling spinning are performed to form a wire rod, then online molten salt isothermal phase change treatment is performed, the wire rod is firstly subjected to front-section molten salt treatment and enters a sorbite phase region from an austenite state to form a structure taking a sorbite structure as a main structure, and then the wire rod is subjected to rear-section molten salt treatment, so that the hot-rolled wire rod is obtained. The method comprises the following steps of: firstly, carrying out heat treatment on the residual austenite, promoting the unconverted residual austenite to be converted into a sorbite structure, simultaneously promoting isothermal tempering of the structure and fusing of a part of sorbite lamellas, and finally, slowly cooling through a roller way to prepare a hot-rolled wire rod of which a microscopic structure comprises a mixed structure consisting of tempered sorbite, tempered ferrite and fused sorbite, so that the material cost can be controlled; the high-strength and high-plasticity performance matching of the wire rod is improved, the tensile strength is 1370-1420 MPa, the percentage reduction of area is 35%-40%, and the mechanical property fluctuation is reduced, so that the wire breaking risk in stranded wire production is reduced, and efficient and stable production is promoted.

The invention discloses super high-strength and high-toughness steel and a preparation method thereof. The super high-strength and high-toughness steel comprises the following components in percentage by mass: 0.18 to 0.35 percent of C, 0.05 to 0.12 percent of Si, 0.30 to 0.50 percent of Mn, less than or equal to 0.008 percent of P, less than or equal to 0.008 percent of S, 0.8 to 1.5 percent of Cr, 0.10 to 0.30 percent of Mo, 2.5 to 3.5 percent of Ni, 0.05 to 0.12 percent of V, 0.01 to 0.05 percent of RE and the balance of Fe. When the content of C is not higher than 0.25%, the alloy contains 0.0005-0.003% of B and the balance of Fe and other inevitable impurities; the preparation process comprises the steps of smelting, homogenization treatment and blank opening, intermediate annealing treatment, large-deformation warm rolling, subzero treatment and low-temperature tempering treatment. The medium-carbon martensite super-high-strength and high-toughness steel with a large enough metastable austenite phase region is obtained through component design, conventional equipment and a production process are utilized for tissue regulation and control, the size of a martensite block is refined to about 1 micron, and the comprehensive mechanical property of the medium-carbon martensite steel is remarkably improved. The material prepared by the invention has ultrahigh strength and high toughness, and is easy for industrial large-scale production and lower in cost.

The invention relates to a high-strength complex-phase hot-rolled wire rod for a 2100MPa-grade stranded wire and a manufacturing method of the high-strength complex-phase hot-rolled wire rod, after a C-Si-Mn-Cr-Mo high-carbon component system is rolled and spun into a wire rod, the wire rod is subjected to online molten salt strong quenching isothermal treatment, so that the wire rod is firstly subjected to front-section molten salt treatment and is cooled at a cooling speed of greater than or equal to 33 DEG C / s, and enters a bainite phase region from an austenite state; the method comprises the following steps: firstly, carrying out first-stage molten salt treatment to promote transformation of austenite into bainite, then carrying out later-stage molten salt treatment to form a structure mainly comprising bainite, carrying out isothermal tempering on the structure, reserving part of untransformed retained austenite, and finally, carrying out roller way slow cooling to promote transformation of the untransformed retained austenite into martensite, and carrying out tempering, the microstructure of the hot-rolled wire rod comprises a complex-phase structure composed of tempered bainite and tempered martensite, the tensile strength of the hot-rolled wire rod can reach 1435-1485 MPa, the percentage reduction of area of the hot-rolled wire rod is 31%-36%, off-line heat treatment of follow-up machining is avoided, and the risk of wire breakage is reduced.

The invention relates to a hot-rolled wire rod for a 2260MPa-grade stranded wire and a manufacturing method of the hot-rolled wire rod, after the high-carbon component design of C-Si-Mn-Cr-Mo-Nb-Al is adopted for rolling and spinning to form the wire rod, online molten salt isothermal toughening treatment is carried out, so that the wire rod is firstly subjected to front-section molten salt treatment and is rapidly cooled, and enters a sorbite phase region from an austenite state to form a structure taking a sorbite structure as a main structure; and then carrying out rear-section molten salt treatment, reducing the circulation volume of molten salt, promoting the unconverted retained austenite to be continuously converted into sorbite, carrying out isothermal tempering, promoting fusing of a part of sorbite lamellar layers, and finally carrying out slow cooling through a roller way, so as to prepare the hot-rolled wire rod of which the microscopic structure comprises a mixed structure consisting of tempered sorbite, ferrite and fused sorbite, the tensile strength can reach 1534-1584 MPa, the percentage reduction of area can reach 33%-38%, and the alloy can be used in the application fields of manufacturing 2260 MPa grade stranded wires and the like without additional heat treatment procedures.

The invention discloses a bevel gear forming grinding temperature prediction method and system and a storage medium, and the method comprises the steps: analyzing a bevel gear heat treatment process, and building a multi-field coupling finite element simulation model of a gear heat treatment process including carburizing, quenching and tempering; and calculating non-uniform tooth surface deformation caused by thermal stress, structural stress and inconsistent surface hardening layer depth. Taking a gear model after heat treatment as an initial model of a gear forming and grinding process, taking a grinding heat flux density three-dimensional distribution result as a thermal load, and combining with a gear forming and grinding geometric contact relationship to establish a helical gear forming and grinding continuous finite element simulation model considering the influence of initial tooth surface non-uniform deformation; and calculating to obtain the temperature distribution of the ground workpiece. According to the method, the influence of the heat treatment process on gear forming grinding can be comprehensively considered, the tooth surface temperature distribution of forming grinding machining is accurately predicted, and the method is crucial for analyzing the influence of the heat treatment process on grinding quality and optimizing process parameters.

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 1960MPa-grade bridge cable and a manufacturing method of the high-strength complex-phase hot-rolled wire rod. V-containing hypereutectoid chemical components are rolled and spun into a wire rod, and then the wire rod is subjected to online molten salt rapid quenching treatment, so that the wire rod passes through front-section molten salt and is cooled at a cooling speed of greater than or equal to 37 DEG C / s, and enters a sorbite phase region from an austenite state; the method comprises the following steps: carrying out molten salt cooling isothermal treatment on austenite to promote transformation of part of austenite to sorbite, then carrying out rear-section molten salt cooling isothermal treatment to promote bainite phase change and isothermal tempering, and finally carrying out roller way slow cooling to prepare a hot-rolled wire rod of which the microstructure comprises a complex-phase structure consisting of tempered bainite and tempered sorbite, according to the steel wire rod, the plasticity of the steel wire rod can be considered, the strength and the structure uniformity of the steel wire rod are further improved, the tensile strength is 1420-1470 MPa, the percentage reduction of area is 39%-44%, the production rhythm is improved, and the steel wire rod is suitable for manufacturing 1960 MPa bridge cables and is beneficial to improving the wire breaking risk and the current situation of unqualified torsion in the wire drawing process.

The invention relates to a 1200MPa-grade high-strength tool steel wire rod and a manufacturing method thereof, after V-containing chemical components are designed, rolled and spun into a wire rod, the wire rod is subjected to online molten salt isothermal quenching treatment, and the wire rod is controlled to enter a bainite phase region from a high-temperature austenite state at a cooling speed greater than or equal to 32 DEG C / s; the steel wire rod with a microscopic structure comprising tempered bainite and ferrite is prepared through isothermal tempering, toughening and destressing treatment, carbide precipitation control and roller way cover opening and slow cooling, so that generation of deteriorated structures such as martensite can be avoided, the structure state can be effectively adjusted, strong plasticity matching of the steel wire rod is achieved, and the service life of the steel wire rod is prolonged. And the tensile strength is 1120-110MPa, the percentage reduction of area is 63-67%, and the steel is suitable for the application fields of manufacturing 1200MPa-grade high-strength tool steel and the like, and is favorable for being directly processed into tool parts after being subjected to cold processing molding.

The invention provides a production method of 440MPa-grade normalized high-strength structural steel for a ship body, and belongs to the field of ship body structural steel manufacturing, the production process route of the steel comprises smelting, die casting, rolling, rapid cooling, finishing, normalizing and tempering, the thickness of a produced steel plate is 8-20mm, and the steel comprises the following chemical components in percentage by mass: 0.06-0.10% of C; si: less than or equal to 0.40%; mn is equal to 0.90%-1.20%; less than or equal to 0.015% of P; s: < = 0.005%; the ratio of Ni to Cr is (0.90%-1.30%): (0.50%-0.65%); v is equal to 0.030 percent to 0.050 percent; cu is equal to 0.15%-0.35%; n is less than or equal to 0.0040%, and the balance is Fe and inevitable impurities. The microstructure of the steel is a bainite tempered structure and ferrite, and the average grain size of the ferrite is smaller than or equal to 10 micrometers. The yield strength of the steel is larger than or equal to 440 MPa, the tensile strength is larger than or equal to 600 MPa, the yield ratio is smaller than or equal to 0.75, the impact absorbing energy at the temperature of 60 DEG C below zero is larger than or equal to 200 J, the ductile-brittle transition temperature is not higher than 80 DEG C below zero, and a product has good corrosion resistance.

The invention relates to a 1100MPa-grade high-strength tool steel wire rod and a manufacturing method thereof, the wire rod adopts a middle-carbon Nb-V-containing chemical component design, after a steel billet is rolled and spun into the wire rod according to the spinning temperature of more than or equal to 860 DEG C, online molten salt semi-quenching isothermal treatment is performed, the wire rod is controlled to be subjected to front-section molten salt treatment, and then the steel wire rod is subjected to hot rolling and hot rolling to obtain the 1100MPa-grade high-strength tool steel wire rod. According to the method, the steel wire rod enters a bainite phase region from a high-temperature austenite state at the cooling speed of more than or equal to 30 DEG C / s to form a structure taking quenched bainite as a main component, and then is subjected to rear-section molten salt heating isothermal tempering and toughening destressing treatment, and finally is subjected to roller way slow cooling to prepare the steel wire rod with a microscopic structure comprising tempered bainite and ferrite, so that the material cost can be reduced, and the production efficiency is improved. The method has the advantages that martensite brittle structures are effectively avoided, the structure state of the hot-rolled wire rod is controlled, the plasticity and cold working performance of the wire rod are improved, the tensile strength of the product can reach 980-1030 MPa, the percentage reduction of area is 61%-66%, and the product can be directly machined into tool parts after cold forming.

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 invention discloses low-alloy NM600-grade wear-resistant steel and a preparation method thereof. The preparation method comprises the following steps: KR desulfurization and smelting treatment; refining and continuous casting treatment; heating and hot rolling treatment; slow cooling and cutting treatment; quenching and tempering treatment; the low-alloy NM600 wear-resistant steel with the hardness of 570-630 HBW is prepared through performance regulation and control treatment, a base body of the low-alloy NM600 wear-resistant steel is nanoscale martensite, and nanoscale precipitated phases and high-density dislocation clusters are distributed in martensite laths. By optimizing chemical components and strictly controlling smelting and heat treatment processes, the wear-resistant steel has excellent wear resistance. Refining of a martensite phase and uniform distribution of a precipitated phase are achieved, and the abrasion resistance and the crack resistance of the steel are further improved. By introducing trace elements such as Nb, Ti and the like, nanoscale precipitated phases such as (NbxTiy) C, NbC, TiC and the like are formed in martensite laths, so that the strength, hardness and wear resistance of the material are greatly improved, and the service life of the steel is prolonged.

The invention belongs to the technical field of aluminum alloy production, and particularly discloses a low-carbon environment-friendly method for producing a 3104 alloy blank with a high secondary aluminum proportion, which comprises the procedures of smelting, melt purification, online degassing filtration, continuous casting and triple continuous rolling, and is characterized in that alloy components are optimized, secondary aluminum waste is used in a large proportion, the Fe content is increased, and the production cost is reduced. Iron and elements such as manganese in the aluminum alloy form intermetallic compounds, the intermetallic compounds can serve as heterogeneous nucleation, obviously refine alloy grains during casting and increase Fe content, the performance of the 3104 alloy blank is improved, meanwhile, aluminum is replaced with iron, the main material cost can be reduced, in addition, due to the fact that the rolling temperature of an inlet of each rack is high, and meanwhile the finish rolling temperature is also high, the service life of the 3104 alloy blank is prolonged. The self-tempering effect is achieved, internal dislocation of materials is eliminated, the blank edge cracking condition is improved, strip breakage caused by the edge cracking problem in the subsequent rolling process is avoided, safe production is guaranteed, the main material cost is reduced, meanwhile, the blank performance is improved, the 3104 alloy blank is efficiently produced in a high-quality mode, and the purposes of low carbon and environment protection are achieved.

The invention provides low-yield-ratio super-thick maritime work steel with excellent core low-temperature toughness and a manufacturing method of the low-yield-ratio super-thick maritime work steel, and belongs to the field of steel and iron material preparation. The low-yield-ratio super-thick marine steel with the excellent core low-temperature toughness comprises the following chemical components in percentage by mass: 0.10%-0.15% of C, 0.35%-0.45% of Si, 1.20%-1.50% of Mn, 3.00%-3.50% of Ni, 0.30%-0.50% of Mo, 0.15%-0.3% of Cr, 0.01%-0.02% of Ti, 0.030%-0.040% of V, 0.050%-0.060% of Nb, 0.0016%-0.0020% of B, 0.15%-0.25% of Cu, 0.060%-0.070% of Al, less than or equal to 0.010% of P, less than or equal to 0.004% of S, less than or equal to 0.39% of CET and the balance of Fe and inevitable impurities. According to the invention, a component design thought of a low-C, Ni-Nb-Mo-Al-B system is adopted, and a three-section rolling and quenching and tempering heat treatment process is combined. Through strict control of smelting continuous casting, controlled rolling and controlled cooling processes and quenching and tempering heat treatment parameters, the super-thick marine steel with excellent comprehensive mechanical properties is successfully prepared. The steel shows good low-temperature toughness in the core part, and meanwhile, the steel has a relatively low yield ratio. According to the low-yield-ratio super-thick maritime work steel with the excellent core low-temperature toughness, the thickness range is 80-150 mm, the yield strength is larger than or equal to 690 MPa, the tensile strength is larger than or equal to 920 MPa, the percentage elongation after fracture is larger than or equal to 20%, the yield ratio is smaller than or equal to 0.77, and the impact energy KV2 at the temperature of-60 DEG C is larger than or equal to 80 J.

The invention relates to a high-strength complex-phase hot-rolled wire rod for a 2360MPa-grade stranded wire and a manufacturing method of the high-strength complex-phase hot-rolled wire rod. After a Mo-V high-carbon component system is rolled and spun into a wire rod, the wire rod is subjected to on-line molten salt weak quenching toughening treatment, so that the wire rod is subjected to front-section molten salt treatment to be quickly cooled, enters a bainite and sorbite mixed phase region from an austenite state, and is subjected to high-temperature heat treatment to form a high-strength complex-phase hot-rolled wire rod; the method comprises the following steps: firstly, carrying out heat treatment on residual austenite to form a structure mainly comprising bainite and sorbite, then carrying out later-section molten salt treatment, increasing the temperature of molten salt, promoting decomposition and conversion of unconverted residual austenite into sorbite, carrying out isothermal tempering, and finally, carrying out roller way slow cooling to prepare a hot-rolled wire rod of which the microscopic structure comprises a complex-phase structure consisting of tempered bainite and tempered sorbite, the method has the advantages that the structure toughness can be regulated and controlled on line, the tensile strength is 1574-1627 MPa, the percentage reduction of area is 28-33%, the mechanical property fluctuation is reduced, the material cost and the production efficiency are both considered, the ultra-high-strength stranded wire can be produced without off-line heat treatment, and the wire breaking risk is reduced.

The invention relates to a hot-rolled wire rod for a 1960MPa-grade stranded wire and a manufacturing method of the hot-rolled wire rod, after high-carbon components of C-Si-Mn-Cr-B are rolled and spun into a wire rod, the wire rod is subjected to rapid online molten salt isothermal treatment, and the wire rod is subjected to front-section molten salt treatment, so that the wire rod is cooled at the cooling speed of more than or equal to 32 DEG C / s and enters a sorbite phase region from an austenite state; the steel wire rod is subjected to rear-section molten salt treatment, the molten salt temperature is reduced, unconverted retained austenite is promoted to be converted into the sorbite structure, meanwhile, isothermal tempering of the structure and fusing of a part of sorbite lamellas are promoted, and finally slow cooling is conducted through a roller way; the microstructure of the hot-rolled wire rod comprises a mixed structure composed of tempered sorbite, ferrite and fused sorbite, the tensile strength is 1305-1355 MPa, the percentage reduction of area is 37%-42%, and the hot-rolled wire rod is used for being used as base metal to manufacture high-strength stranded wires and other application fields and is beneficial to reducing the risk of wire breakage.

The invention relates to an ultrahigh-strength low-temperature maritime work wide thin steel plate with good cold working performance and a manufacturing method of the ultrahigh-strength low-temperature maritime work wide thin steel plate. The steel plate comprises the following chemical components in percentage by weight: 0.04% to 0.08% of C, 0.1% to 0.4% of Si, 1.0% to 1.6% of Mn, 5.0% to 8.0% of Ni, 0.4% to 0.7% of Cr, 0.8% to 1.2% of Mo, 1.0% to 1.5% of Cu, 0.2% to 0.3% of V, 0.025% to 0.045% of Ti, 0.025% to 0.040% of Zr, 0.03% to 0.06% of Als, 0.002% to 0.005% of B, less than or equal to 0.005% of P, less than or equal to 0.001% of S and the balance of Fe and inevitable impurities. A low-carbon component design is adopted, elements such as V and Ti are added, and elements such as Ni, Cr, Mo, B and Zr are compositely added; a high-cleanliness smelting control technology, an electroslag remelting technology and a composite ply rolling technology are adopted, a two-stage rolling process, a transverse-longitudinal rolling process and a heat treatment process of quenching, two-phase region quenching and critical temperature tempering are matched, and the finally obtained wide and thin steel plate has excellent comprehensive mechanical properties.

The invention discloses an yttrium-rich neodymium-iron-boron magnet and a preparation method thereof, and belongs to the technical field of rare earth permanent magnet material preparation. The preparation method comprises the following steps: mixing yttrium-rich neodymium-iron-boron matrix alloy powder with grain boundary doped alloy powder containing Gd and / or Ho, and carrying out compression molding and sintering tempering treatment to obtain a first yttrium-rich neodymium-iron-boron magnet. According to the invention, the grain boundary doped alloy powder containing Gd and / or Ho is added into the yttrium-rich neodymium iron boron matrix alloy powder and then is sintered, so that a continuous and uniform non-magnetic thin-wall grain boundary phase structure is formed in the grain boundary, and the coercive force of the magnet is enhanced. Dy and / or Tb heavy rare earth element grain boundary diffusion is carried out based on the first yttrium-rich neodymium-iron-boron magnet after grain boundary modification, a second yttrium-rich neodymium-iron-boron magnet is obtained, the diffusion depth of Dy and / or Tb in the magnet can be increased, the utilization rate can be increased, the cost can be reduced, the coercivity of the magnet can be improved, and the adverse effect of Dy and / or Tb on residual magnetism can be reduced.

The invention belongs to the field of metal materials, and provides a hard alloy wear-resistant steel ball suitable for mine ore grinding and a preparation method thereof.The hard alloy wear-resistant steel ball is prepared from waste steel pig iron as a basic raw material and chemical components including 2.1%-2.2% of C, 9.8%-10.0% of Cr, 0.10%-0.20% of V and 0.03%-0.06% of Ti; a core-shell precipitated phase microstructure design with MN / MCN as a hard core and chromium carbonitride as a gradient self-passivation shell layer is formed through medium-frequency induction furnace smelting, controlled nitrogen introduction establishment of a V-Ti-C-N microalloy system, bottom pouring solidification and austenitizing quenching and tempering heat treatment processes, and the performance indexes that the surface hardness is HRC60-63 and the core hardness is HRC54-58 are achieved; the average particle size of a core-shell precipitated phase is in dispersed distribution of 20-200nm, the shell thickness is 5-50nm, and the alloy steel ball has excellent wear resistance and corrosion resistance under the high-impact and high-wear working conditions of wet ore grinding, solves the problem of insufficient wear resistance and corrosion resistance of a traditional alloy steel ball, and has wide mine ore grinding application value.

The invention discloses ultrafine heterostructure martensitic steel based on Mo segregation induction and a heat treatment process of the ultrafine heterostructure martensitic steel. The martensitic steel comprises the following chemical components in percentage by weight: 0.4-0.7% of C, 0.3-1.0% of Mn, 1.0-2.0% of Si, 0.2-1.5% of Cr, 0.01-3.5% of Ni, 0.2-0.8% of Mo, less than or equal to 0.03% of P, less than or equal to 0.03% of S and the balance of Fe. The method comprises the following steps: firstly, obtaining a pearlite type structure rich in Mo cementite through a normalizing or tempering process by utilizing the characteristic that Mo element is easily enriched in the cementite; then austenitizing treatment is conducted through a rapid heating technology by means of the characteristics that in the austenitizing process, the dissolving speed of molybdenum-rich cementite is low, and the diffusion speed of the Mo element is low, and a superfine austenite structure with the Mo element distributed unevenly is obtained, that is, a nanometer / submicron Mo-rich area exists in superfine austenite; and then quenching and tempering treatment are carried out, a tempered martensite structure with a superfine heterostructure is obtained, so that excellent strength and plasticity are obtained, the yield strength of the alloy can reach 2000-2500MPa, the tensile strength can reach 2100-2700MPa, and the ductility is 6-12%.

The invention provides a method for preparing a high-coercivity sintered neodymium-iron-boron magnet, and belongs to the technical field of rare earth permanent magnet material preparation, and the method comprises the following steps: 1, taking the sintered neodymium-iron-boron magnet as a base material, and removing an oxide layer through alkali washing deoiling, ultrasonic water washing and acid pickling cleaning; 2, taking the Pr-Dy-Cu-Ga quaternary alloy as a diffusion source, and cutting the Pr-Dy-Cu-Ga quaternary alloy into slices; 3, attaching the thin sheet to the surface of a base material for diffusion heat treatment; fourthly, low-temperature tempering is conducted; 5, testing a room temperature demagnetization curve of the sample; light rare earth Pr replaces a part of heavy rare earth Dy and is matched with Cu and Ga elements in a certain proportion to be smelted to obtain quaternary alloy, the quaternary alloy with low heavy rare earth serves as a diffusion source, the microscopic characteristics of the magnet are improved, grain boundary phase distribution is optimized, and under the condition that residual magnetism and the maximum magnetic energy product are slightly reduced, the coercive force of the sintered neodymium-iron-boron magnet is improved; and terbium and dysprosium are not used, so that the use amount of heavy rare earth elements and the production cost are reduced.

The invention discloses a method for efficiently smelting molten iron through electric furnace melting separation of medium-low-grade iron ore direct reduction iron, which comprises the following steps: (1) uniformly mixing and blending different kinds of medium-low-grade iron ore to prepare oxidized pellets; (2) adopting a hydrogen-based shaft furnace to carry out hydrogen-based reduction, so as to prepare medium-low-grade DRI; and (3) the medium-low-grade DRI is subjected to hot charging and hot conveying to a melt separation electric furnace, carbon and a tempering agent are added for melt separation, and after melt separation is completed, high-purity molten iron and molten slag are obtained through slag-iron separation. According to the method, a small amount of carbon is adopted for reducing the medium-low-grade DRI, the melting temperature is reduced by adding the tempering agent, the high-purity molten iron is obtained, and the problems that the low-grade DRI is fed into an electric furnace for steelmaking, too many impurities exist, and power consumption is too large are remarkably solved.

The invention provides a 10.9-grade non-quenched and tempered cold heading steel wire rod and a production method thereof. The 10.9-grade non-quenched and tempered cold heading steel wire rod comprises the following chemical components: 0.23-0.27% of C, 0.30-0.50% of Si, 1.45-1.55% of Mn, less than or equal to 0.025% of P, less than or equal to 0.025% of S, 0.40-0.50% of Cr, 0.025-0.050% of Ti, 0.0025-0.0050% of B, less than or equal to 0.0050% of N and more than or equal to 0.015% of [Ti]-3.5 * [N]. According to the invention, on the basis of component design, a controlled rolling process deformation induced phase change, an online salt bath isothermal treatment cooling process and an artificial aging process are matched, so that rapid cooling and isothermal phase change of the wire rod are realized, and the prepared wire rod is uniform in through ring mechanical property, high in yield ratio, good in plasticity and long in fatigue life. The steel wire rod can be used for directly cold-drawing the steel wire without annealing, and the cold-drawn steel wire can meet the performance requirement of a 10.9-grade fastener without quenching and tempering after being formed. According to the production method of the wire rod, the production process can be simplified, the fastener production period is shortened, the cost is reduced, meanwhile, the energy consumption is reduced, and the method conforms to the current green and low-carbon development route.

The invention discloses a pipeline steel plate for carbon dioxide conveying and a preparation method thereof. In the heating procedure of the preparation method, the soaking temperature is TNbC + (40-100) DEG C, and the soaking time is 30-50 min; in the first hot rolling procedure, multiple passes are included, the plate thickness after rolling is 3.2-4.2 t, the initial rolling temperature is Tnr + (5-25) DEG C, and the final rolling temperature is Tnr + (0-20) DEG C; in the water cooling process, the final cooling temperature is Ar3-20 DEG C-Ar3 + 15 DEG C; in the second hot rolling procedure, multiple passes are included, the plate thickness t after rolling is larger than or equal to 38 mm, and the initial rolling temperature and the final rolling temperature are both Ar3-20 DEG C-Ar3 + 15 DEG C; in the ultrafast water cooling process, the water inlet temperature is larger than or equal to Ar < 3-30 > DEG C, the final cooling temperature is Bs-(460-300) DEG C, and the cooling rate is 9-22 DEG C / s; and in the air-cooling self-tempering process, the steel plate is air-cooled to the room temperature on a cooling bed.

The present invention relates to a fatigue-resistant and corrosion-resistant 500 MPa-grade steel plate for marine wind power, the chemical composition of which is as follows, by mass percentage: C: 0.10%-0.12%, Si: 0.20%-0.30%, Mn: 1.20%-1.40%, P≤0.010%, S≤0.005%, Nb: 0.030%-0.040%, Ti: 0.018%-0.030%, Ni: 0.28%-0.38%, Cu: 0.35%-0.55%, Al: 0.020%-0.050%, Pcm being controlled to be ≤0.25%, and the remainder being Fe and unavoidable impurity elements. The 500 MPa-grade steel plate for marine wind power of the present invention is produced using a TMCP+tempering process, and has a thickness of 30 mm-60 mm, a yield strength of ≥500 MPa, a tensile strength of 600-760 MPa, an elongation after fracture of ≥17%, and a core impact energy of ≥120 J at -30℃. Corrosion resistance is improved by 50% or more compared with conventional 355 MPa-grade steel plate for marine wind power. After the steel plate is welded by submerged arc welding with a heat input of ≥35 kJ / cm, the tensile strength of the welded joint is ≥600 MPa, and the impact energy at -30℃ is ≥80 J; under conditions of a stress ratio of 0.5, the fatigue limit of a welded joint after 107 cycles of axial loading is ≥450 MPa. The steel has the characteristics of high strength, fatigue resistance, corrosion resistance and easy welding, and can meet the development requirements of safe service, high strength and light weight for marine wind power facilities.