966results about "Quenching agents" 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 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 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 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 hot-rolled wire rod for a 2100MPa-grade stranded wire and a manufacturing method thereof, after a high-carbon and high-silicon component system is rolled and spun into a wire rod, the wire rod is cooled at a cooling speed of more than or equal to 31 DEG C / s through online molten salt sorbite regulation and control treatment, and enters a sorbite phase region from an austenite state; the method comprises the following steps of: forming a structure mainly comprising a sorbite structure, performing isothermal tempering, promoting fusing of a part of sorbite lamellas, and finally performing roller way cover opening and slow cooling to prepare the hot-rolled wire rod of which the microscopic structure comprises a mixed structure consisting of tempered sorbite, tempered ferrite and fused sorbite, so that alloy components can be simplified, and the strong plasticity matching and the structure uniformity of the wire rod can be improved; the tensile strength is 1420-1470 MPa, the percentage reduction of area is 36%-41%, the composite material is used for the application field of manufacturing 2100 MPa grade stranded wires and the like, off-line heat treatment can be avoided, and the risk of wire breakage during downstream drawing and twisting 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 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 relates to the technical field of low-temperature studs and bolts, and discloses a low-temperature stud steel hardenability optimization treatment method which comprises the steps of S1, a pretreatment method, S2, quenching method optimization, S3, tempering method optimization, S4, a post-treatment method and S5, a performance verification method. According to the method, the low-temperature impact stability is remarkably improved, the low-temperature impact energy of the material at about-100 DEG C can stably reach 35 J or above by accurately controlling the proportion of alloy elements and optimizing the heat treatment process (for example, the tempering temperature is increased to 640 DEG C or above and the heat preservation time is prolonged), the low-temperature impact energy is improved by about 20%-30% compared with a traditional process, and the problem that the low-temperature impact performance of the wire rod fluctuates is thoroughly solved; and the service safety in a low-temperature environment is ensured.

The invention belongs to the technical field of bearing manufacturing, and particularly relates to a quenching and tempering heat treatment method for a large heavy-duty bearing ring piece, which is suitable for quenching and tempering heat treatment of a thick large-section ring piece. And the thick and large-section ferrule ring piece is heated to the quenching temperature in a segmented and stepped mode, the ferrule ring piece is hoisted to a circulating water pool to be subjected to water cooling after heat preservation is completed, cooling is conducted till the surface temperature of the ring piece is lower than 100 DEG C, and the quenched ferrule ring piece is timely charged into a furnace to be tempered twice. The surface of the ferrule ring subjected to quenching and tempering heat treatment is free of cracks, the deformation degree is small, a martensite structure with the full cross section quenched thoroughly can be obtained, and the uniformity of the surface layer, the core structure and the performance of the ferrule ring with the thick and large cross section can be greatly improved. In addition, the quenching and tempering heat treatment process is simple to operate, and the consistency of the performance of the ferrule ring pieces in all batches is easily ensured. The method is not limited to a process of a large heavy-duty bearing ring piece, is also very suitable for thermal refining of other large forgings, and solves the defect problems of non-uniform structure, unstable performance and the like.

The invention belongs to the technical field of metal heat treatment, and relates to a rapid quenching and tempering process of high-strength steel, which comprises the following steps: preheating a steel workpiece, then transferring to a vacuum induction furnace, heating to a first quenching temperature, preserving heat, and then periodically fluctuating and controlling the temperature to obtain a quenched workpiece; performing high-frequency induction heating on the quenched workpiece to a first tempering temperature, preserving heat, and performing water cooling after heat preservation to finish first tempering treatment; and then carrying out medium-frequency induction heating to a second tempering temperature under the alternating magnetic field, preserving heat, and air-cooling to room temperature along with the furnace after heat preservation is finished, so as to finish second tempering treatment. By optimizing key steps such as preheating, quenching, cooling and tempering in the heat treatment process, the comprehensive mechanical property of the high-strength steel is remarkably improved, rapid heating and structure homogenization are achieved through two-section preheating, and the problem of workpiece deformation or cracking caused by rapid heating in a traditional preheating process is solved.

A quenching-attitude-setting program causes a computer to execute setting of the quenching attitude of an object to be quenched. The quenching-attitude-setting program causes the computer to execute a first process of dividing a virtual model obtained by modeling the object to be quenched into a plurality of elements based on a world coordinate system including a vertical direction as an axis, and a second process of evaluating whether a vapor film generated when the virtual model is immersed in cooling oil remains for each of the plurality of elements. In the quenching-attitude-setting program, the first process and the second process are repeated while changing an attitude of the virtual model with respect to the world coordinate system until the number of elements evaluated as having the vapor film remaining satisfies a preset condition.

The purpose of the present invention is to provide: a steel material which has excellent fatigue characteristics in a high-pressure hydrogen environment and which is suitable for use in a steel structure in a high-pressure hydrogen environment, such as a line pipe for a natural gas (the natural gas is a gas mainly composed of a hydrocarbon such as methane or ethane) containing 100% hydrogen or hydrogen having a hydrogen partial pressure of 1 MPa or more; and a method for producing the steel material. A steel pipe and a manufacturing method thereof. A steel material having excellent fatigue characteristics in hydrogen, the steel material having a specific component composition and a specific structure, and having a crack propagation rate da / dN of 1.0 * 10 <-6 > m * cycle <-1 > or less when a stress expansion coefficient in hydrogen of 1 MPa or more is 20 MPa square root of m.

A golf club head has a loft no less than 38°. The golf club head also comprises a material having a material composition that includes an Iron content that by weight is highest of all constituents. The material composition also has a Chromium content no less than 10.5% by weight and a Nickel content no greater than 0.5% by weight.

A corrosion-resistant rolled clad steel plate for high-temperature equipment and a manufacturing method therefor. The clad steel plate comprises a base material, a cladding layer, and a transition layer between the base material and the cladding layer; in percentage by weight, the base material is prepared from the following components: C: 0.08%-0.18%, Si: 0.01%-0.6%, Mn: 0.30%-0.70%, Ti: 0.009%-0.015%, Als: 0.010%-0.015%, Nb: 0.0010%-0.050%, Cr: 1.85%-3.85%, Mo: 0.5%-1.55%, B: 0.0007%-0.0050% N: 0.0025%-0.0050%, P ≤ 0.010%, S ≤ 0.010%, O ≤ 0.004%, and the balance being Fe and other unavoidable impurities. The present invention fully accounts for interfacial characteristics of the clad steel plate, ensures the corrosion resistance of the cladding layer stainless steel, is suitable for high-temperature equipment at operating temperatures of 450-530°C, and is widely applicable in energy industries such as thermal energy, petroleum refining, and the chemical industry.

One embodiment of the present invention provides a high-strength thin-wall API steel material having excellent deformation stability and a manufacturing method thereof, the thin-wall API steel material comprising, in weight %, C: 0.05-0.15 %, Si: 0.5 % or less (except 0 %), Mn: 0.5-2.5 %, Nb: 0.05 % or less (except 0 %), V: 0.004 % or less (except 0 %), Mo: 0.03-0.2 %, Cr: 0.1-0.3 %, P: 0.03 % or less (except 0 %), S: 0.015 % (except 0 %), Al: 0.05 % or less (except 0 %), N: 0.01 % or less (except 0 %), Fe and other inevitable impurities in a balance, and a microstructure comprising, in area %, 10-30 % of ferrite having an average grain size of 15-30 μm and a balance of bainite, the thin-wall API steel material comprising 3000 / μm 2 V-based precipitates below.

The present invention pertains to a steel plate that can be appropriately used for marine structures such as wind power installation ships and marine plants. More specifically, the present invention pertains to a steel plate having high strength and excellent low-temperature impact toughness and a method for manufacturing same.

The present disclosure provides a high-vanadium high-speed steel and preparation method therefor, and use thereof, which relate to the technical field of high-vanadium high-speed steel. The preparation method includes: smelting raw materials to form a melt; impacting the melt to a cooling platform to form a high-vanadium high-speed steel casting billet; and performing a spheroidizing annealing treatment and a quenching and tempering treatment, so as to obtain a resultant. The spheroidizing annealing treatment includes: heating the high-vanadium high-speed steel casting billet to 820-910° C.; holding for 2-4 h; then cooling down to 450-550° C. at a cooling rate larger than 40° C. / h; and then air cooling to a room temperature.

The invention discloses a microalloyed medium-carbon high-speed wheel with good comprehensive mechanical performance and a heat treatment method and a preparation method of the microalloyed medium-carbon high-speed wheel. The microalloyed medium-carbon high-speed wheel comprises, by mass, 0.50%-0.55% of C, 0.30%-0.40% of Si, 0.70%-0.80% of Mn, 0.25%-0.35% of Cr, 0.03%-0.04% of Mo, 0.04%-0.12% of V, smaller than or equal to 0.002% of Ti, smaller than or equal to 0.020% of Al, 0.004%-0.010% of N and the balance Fe and inevitable impurity elements. On the basis that the content of C is not increased, the wheel obtains good toughness matching performance by regulating and controlling the content of Cr, Mo and V elements, and the wheel has high strength, high hardness, high impact toughness and high fracture toughness and has good use safety performance.

A thermoforming method for a high-strength steel part. A hot stamping die comprises an upper die (1) and a lower die (2); the lower die is located in a water tank (3); the water tank is used for containing hot water above 60°C; during use, the lower die is partially or completely immersed in hot water; the lower die is provided with at least two sheet supports; each sheet support comprises a fixed rod (7) vertically fixed on the bottom surface of the water tank; the upper end of the fixed rod is rotatably connected to a cross beam (8) by means of a rotating shaft (9); one ends of the cross beams of the sheet supports cooperate with each other to support sheets, and the other ends of the cross beams are rotatably connected to the upper ends of pull rods (10); the lower ends of the pull rods are connected to the fixed rods by means of springs (11); and in an initial state, the height of the cross beams is greater than the liquid level of hot water. Further provided is a low-melting-point coating part with a low micro-crack depth. The low-melting-point coating part comprises a substrate and a low-melting-point coating located on the surface of the substrate; the low-melting-point coating part is formed by hot stamping; micro-cracks are generated in the substrate and the low-melting-point coating in the forming process; and most of the micro-cracks extending from the low-melting-point coating to the substrate are located at concave fillet tangent points of the low-melting-point coating part, and a small part of the micro-cracks extending from the low-melting-point coating to the substrate are located at positions other than the concave fillet tangent points of the low-melting-point coating part. Further provided are a thermoforming method for the low-melting-point coating part, a hot bath edge cutting device for the high-strength steel part, and a method for using the hot bath edge cutting device. According to the thermoforming method, in the direct forming process, the micro-crack expansion process of the low-melting-point coating and the substrate is effectively inhibited, the service life of the low-melting-point coating part is ensured, and excellent corrosion resistance is shown.

The present invention relates to the technical field of hot stamping steel. Disclosed is a soaking-type stamping method and apparatus for hot-formed steel, comprising the following steps: step 1: transporting a prepared blank into a furnace chamber for austenitizing heating, the blank being made of a hot-formed steel material; and step 2: immersing a lower forming punch into a liquid medium within a tank assembly, and placing the heated blank onto a material support frame by means of a loading manipulator, the tank assembly being internally provided with the liquid medium. A soaking-type stamping method is used in the present invention, which, compared to the direct hot-forming method in the prior art, optimizes the structure of a mold, reduces the machining of water channels in hot stamping devices of the prior art, and shortens the processing cycle and reduces costs while broadening the applicable range of materials, solving the issue of oxide scale on uncoated plates and the lime problem of galvanized steel plates, and having low investment costs and being easily controlled for automation.

The purpose of the present invention is to provide: a high-strength seamless steel pipe which is for a high-pressure hydrogen vessel and has excellent hydrogen embrittlement resistance; and a manufacturing method therefor.　This high-strength seamless steel pipe for a high-pressure hydrogen vessel has a specific composition and has a structure in which the area ratio of tempered martensite is at least 95%, wherein at least 50 mass% of Mo contained in the steel is contained in precipitates, at least 50 mass% of Mo contained in the precipitates is contained in precipitates having a diameter of at most 50 nm, and the tensile strength TS is at least 850 MPa.

The application provides a corrosion-resistant super-large line energy welding steel plate and a production method thereof, relates to the technical field of alloys, and the steel plate adopts a corrosion-resistant alloying component system with composite addition of Ce, Sn and Cu. The addition of Ce can improve the corrosion resistance of the steel plate, and Ce is easy to combine with oxygen to generate spherical oxides and has the ability to induce the nucleation of intracrystalline acicular ferrite, thereby improving the welding performance of the steel plate. On the basis of the comprehensive design of chemical components, the process parameters of rolling and cooling processes are accurately controlled to obtain the corrosion-resistant super-large line energy welding steel plate with good comprehensive performance.

The invention belongs to the technical field of quenching oil, and discloses low-carbon steel quenching oil as well as a preparation method and application thereof, and the low-carbon steel quenching oil comprises the following components in percentage by mass: 88%-94% of base oil, 3%-7% of a cooling accelerant, 1.5%-2% of a dispersing agent, 0.5%-1.5% of a brightener and 1%-3% of a composite antioxidant, wherein the base oil comprises first base oil and second base oil in a mass ratio of 1: (1.8-2.2), the kinematic viscosity of the first base oil at 40 DEG C is 23 mm < 2 > / s-27 mm < 2 > / s, the kinematic viscosity of the second base oil at 40 DEG C is 86 mm < 2 > / s-90 mm < 2 > / s, and the flash points of the first base oil and the second base oil are both higher than 210 DEG C. According to the quenching oil, the industrial pain points that the cooling speed of traditional quenching oil is difficult to control, a workpiece is prone to deformation and cracking, and the performance is difficult to consider are precisely overcome, perfect balance of ultrahigh strength and excellent toughness is achieved on the basis that it is guaranteed that a material forms an ideal microstructure, and more reliable safety performance support is provided for an automobile anti-collision beam.

The invention relates to the technical field of wear-resistant materials, in particular to a semi-autogenous-grinding forged wear-resistant steel ball and a preparation method thereof.The semi-autogenous-grinding forged wear-resistant steel ball comprises, by mass, 0.75%-0.85% of C, 2.1%-3.2% of V + Mn, 1.8%-2.2% of Cr, 0.25%-0.45% of Mo, 0.15%-0.35% of Ni, 0.25%-0.4% of Cu, 0.04%-0.08% of Nb, 0.01%-0.06% of Ti, 0.003%-0.008% of B, smaller than or equal to 0.021% of P, smaller than or equal to 0.020% of S and the balance Fe and inevitable impurities. And the steel ball blank is subjected to heating forging, quenching, tempering treatment and natural cooling, and then the wear-resistant steel ball is obtained. The prepared wear-resistant steel ball is high in surface and core hardness, high in impact energy, remarkably improved in wear resistance and good in hardness uniformity.

The invention relates to the technical field of metal heat treatment, in particular to a silicon alloy steel bearing ring high-temperature salt bath quenching process for a high-temperature load environment, which comprises the following steps: S1, carrying out surface sand blasting treatment on a silicon alloy steel bearing ring; s2, stepped heating-heat preservation-cooling treatment is carried out, and the uniformly austenitized ferrule is obtained; s3, the uniformly austenitized ferrule is immersed in a composite salt bath; s4, staged cooling treatment of an air cooling stage and an oil cooling stage is conducted in sequence; s5, the martensite matrix ferrule is subjected to subzero treatment and staged heating; and S6, multi-stage tempering treatment with different temperature gradients is conducted, and the final high-temperature bearing ring is obtained. Through the combined process of stepped austenitizing, composite salt bath ultrasonic quenching, graded cooling, deep cooling and multi-stage tempering, homogenization and stabilization of the structure of the bearing ring are achieved, and the dimensional stability and the tempering resistance of the bearing ring in the high-temperature load environment are improved.

The invention relates to the technical field of research and development of low-temperature bolt steel, and discloses a low-temperature impact performance control process for low-temperature bolt steel. Comprising the steps that S1, in the steelmaking refining stage, purity and uniformity control is conducted, S2, casting blank homogenization treatment is conducted, stress relief and structure regulation are conducted, S3, a heat treatment core process is conducted, structure and toughness balance regulation is conducted, and S4, online detection and dynamic feedback are conducted, and performance stability is guaranteed. By accurately controlling the element proportion of carbon (C), silicon (Si), manganese (Mn), chromium (Cr) and molybdenum (Mo) in steel and combining with an optimized heat treatment process (such as 860 DEG C oil quenching and 640-650 DEG C high-temperature tempering, and the heat preservation time is prolonged to 120 minutes or more), the V-shaped notch impact energy of the material in the environment of-101 DEG C stably reaches 35 J or more, the impact energy of part of samples can reach 50 J or more, and the impact energy of the part of samples can reach 50 J or more. The problem that the low-temperature impact performance is insufficient after wire hardening and tempering is thoroughly solved, and it is ensured that the brittle failure resistance of the bolt is remarkably improved in the ultralow-temperature environment.

The invention relates to a production line configured to convey the metal product along a conveying path, which production line comprises, along the conveying path, an induction heat treatment furnace configured to heat the metal product by induction while the metal product is being conveyed, and a laser stripping unit configured to strip, using at least one laser, at least one surface of the metal product while the metal product is being conveyed.

The invention relates to the technical field of metal material strengthening treatment, in particular to a micropitting-resistant wind driven generator gear carburizing and quenching composite strengthening process which comprises the following steps: S1, gear blank pretreatment and surface activation; s2, gradient carburizing strengthening treatment; s3, grain refinement annealing treatment; s4, step quenching strengthening treatment; s5, performing deep cooling and thermal cycle treatment; s6, directional tempering regulation and control treatment; s7, composite shot peening strengthening treatment is conducted; and S8, an antifriction composite film layer is deposited on the surface of the gear subjected to shot peening strengthening in the S7. According to the method, through a synergistic strengthening mechanism of gradient carburization, step quenching, structure regulation and control and surface functionalization, the residual stress distribution and tribological performance are optimized while the high surface hardness of the gear is kept, and the technical problems that in a traditional technology, the carburized layer is concentrated in stress, uneven in structure, single in surface performance and the like are solved.

The present traverse hardening device is a device that performs traverse hardening on a shaft-like body in which a large diameter portion having a relatively large outer diameter and a small diameter portion having a relatively small outer diameter are connected via a level difference portion, the device including: a plurality of first divided coils annularly arranged around a motion center line at a first position on the motion center line; a plurality of second divided coils annularly arranged around the motion center line at a second position different from the first position on the motion center line; a first divided coil drive unit configured to bring the first divided coils close to and away from the motion center line; a second divided coil drive unit configured to bring the second divided coils close to and away from the motion center line; and a control unit configured to control the first divided coil drive unit and the second divided coil drive unit.

The present invention provides a thick, fatigue-resistant, easily weldable, high-strength steel plate for wind power generation and a preparation method thereof. The steel plate comprises the following chemical composition by mass: C: 0.12% to 0.15%, Si: 0.15% to 0.35%, Mn: 1.30% to 1.50%, P ≤ 0.015%, S ≤ 0.005%, Nb: 0.015% to 0.030%, V: 0.015% to 0.030%, Ti: 0.005% to 0.020%, Al: 0.005% to 0.030%, with the remainder being Fe and unavoidable impurities. The preparation method comprises the steps of smelting, refining, continuous casting, heating, and rolling. The use of a low-C, high-Mn, Nb+V+Ti composite microalloying significantly inhibits austenite grain growth. The use of a normalizing rolling process results in a short process flow, low cost, and strong production line adaptability.