229 results about "Hardenability" patented technology

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 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 discloses a dual-motor dual-rotor flywheel energy storage device which comprises a shell which is arranged in a sealed mode. The flywheel is connected with a motor and arranged on the inner wall of the shell, and the flywheel is arranged to be in a split type; the first wheel body is arranged right above the second wheel body, so that the axial thickness of the flywheel is increased, the energy storage capacity of the whole device is improved, meanwhile, the problem of insufficient quenching depth caused by a flywheel with a large axial size can be solved, and the flywheel is arranged into a split type, so that the axial thickness of a forge piece can be reduced, and the hardenability is improved. The two groups of motors are respectively connected with the first wheel body and the second wheel body, so that the heat dissipation areas of the stators and the rotors in the motors are increased, and the problem of heat dissipation caused by the increase of the structural sizes of the stators and the rotors of the motors due to higher motor power is solved.

The invention relates to the field of ferrous metallurgy and forge piece manufacturing, in particular to high-toughness, ultra-pure and large-quenching-depth 40CrNiMoRE rare earth special steel for a large ring piece and a preparation method of the high-toughness, ultra-pure and large-quenching-depth 40CrNiMoRE rare earth special steel. The invention relates to a high-temperature-resistant steel material, which comprises the following chemical components in percentage by weight: 0.3 to 0.5 percent of C, 0.1 to 0.5 percent of Si, 0.4 to 0.8 percent of Mn, 0.5 to 1.5 percent of Cr, 0.5 to 1.5 percent of Ni, 0.1 to 0.5 percent of Mo, 0.05 to 0.30 percent of V, 0.0005 to 0.0030 percent of B, 0.005 to 0.030 percent of RE and the balance of Fe and inevitable impurities. Through V, B and RE comprehensive microalloying, molten steel purification, inclusion modification and grain refinement, the hardenability is improved, and the surface quenching layer depth, hardness uniformity and impact toughness are ensured. And moreover, the high-toughness, ultra-pure and large-quenching-depth large ring piece is obtained through preparation technologies such as pure smelting, airtight protection pouring and uniform deformation, and the technical problems that an existing large ring piece is low in purity, poor in toughness, insufficient in hardenability, cracked in surface quenching and the like can be effectively solved.

The invention relates to a high-speed rail gear steel bar produced through a continuous casting and rolling process and a manufacturing method of the high-speed rail gear steel bar, and belongs to the technical field of metallurgy. The steel comprises the following chemical components in percentage by mass: 0.15 to 0.20 percent of C, less than or equal to 0.40 percent of Si, 0.50 to 0.90 percent of Mn, 1.50 to 1.80 percent of Cr, less than or equal to 0.025 percent of P, less than or equal to 0.025 percent of S, less than or equal to 0.30 percent of Cu, less than or equal to 0.005 percent of Ti, 0.02 to 0.05 percent of Al, 1.40 to 1.70 percent of Ni, 0.25 to 0.35 percent of Mo, 0.015 to 0.035 percent of Nb, less than or equal to 0.0030 percent of Ca, 0.0090 to 0.0150 percent of N, less than or equal to 0.0012 percent of [O], less than or equal to 0.0001 percent of [H] and the balance of Fe and inevitable impurity elements. A narrow hardenability bandwidth control technology is realized by establishing a hardenability prediction model, accurately controlling smelting components and uniformly controlling solidification components, and the hardenability bandwidth of the material is less than or equal to 4 HRC; the gear steel is subjected to high-temperature carburization at 980 DEG C for 4 h, and the grain size reaches the level 5 or above.

The invention relates to a steel wire rod for a non-quenched and tempered fastener, a production method of the steel wire rod and the fastener, and the steel wire rod is characterized in that through component design, an element B is added on the basis of strengthening elements such as carbon, silicon and manganese, so that excellent hardenability and plasticity of steel are guaranteed; the tensile strength of the steel wire rod obtained through the production process of converter smelting, LF refining, bloom continuous casting, cogging, steel wire rod rolling and offline salt bath of the steel wire rod is 1050-1250 MPa, and the percentage reduction of area is 65-70%; the steel wire rod is subjected to drawing and cold heading to produce the fastener, thermal refining can be omitted, the technical requirements of the 12.9-grade fastener can be met, and the production cost and the carbon emission are effectively reduced.

The invention discloses a rolling manufacturing method of low-decarburization medium-chromium round steel for a caterpillar track link and a product of the rolling manufacturing method, and belongs to the technical field of alloy steel rolling. The method comprises the following steps: smelting molten steel, wherein the molten steel comprises the following components in percentage by mass: 0.28-0.34% of C, 0.15-0.35% of Si, 0.50-0.85% of Mn, less than or equal to 0.030% of P, less than or equal to 0.030% of S, 0.80-1.10% of Cr, less than or equal to 0.30% of Ni, 0.10-0.30% of Mo, less than or equal to 0.30% of Cu, 0.010-0.060% of Al and the balance of Fe and impurities; lF refining, RH vacuum degassing (the time is longer than or equal to 20 min, and the hydrogen content is smaller than or equal to 1.5 ppm), electromagnetic stirring continuous casting (the superheat degree is 15-25 DEG C), slow cooling (longer than or equal to 12 h), segmented heating (the total time is shorter than or equal to 200 min, and the residual oxygen content is lt, 3%), multi-stage high-pressure water descaling (the pressure before finish rolling is 30-35 MPa) and hot continuous rolling (the compression ratio is larger than or equal to 6) are conducted. The total decarburized layer depth of the obtained round steel is smaller than or equal to 0.30 mm, and the round steel has high hardenability, excellent mechanical property and low surface defect rate and is suitable for heavy-load components such as a hydraulic excavator caterpillar track link.

The invention relates to the field of materials and processes for automobile parts, in particular to a homogenization evaluation method for hardenability of Ti-containing carburizing steel and application. According to different specifications and different looseness and segregation levels of the round steel, sampling regulation is carried out on the center part and the center part of the section of the Ti-containing carburizing steel round steel, and the hardenability and the hardenability bandwidth of the carburizing steel can be more truly reflected. When the hardness of the tail end hardenability sample is detected, two surfaces equidistant from the circle center of the section of the round steel are detected, a telecentric surface far away from the circle center of the section of the round steel and a proximal surface close to the circle center of the section of the round steel are detected, and compared with the current national standard, the detection result is more scientific and accurate. The method can be applied to almost all carburized steel bars with large component fluctuation, the uniformity is truly reflected, technicians can select raw materials with proper hardenability bandwidth to be applied to shaft gear parts with different size characteristics and using performance requirements, and the application prospect is very wide.

The invention discloses a preparation method of a novel low-alloy steel solid welding wire. The preparation method comprises the following steps of S1, raw material smelting, S2, a hot working stage, S3, a cold working stage, S4, surface treatment and S5, quality detection. During raw material selection, C-Mn-Si is adopted as a basic alloy, the content of C is 0.06-0.12%, the content of Mn is 1.2-1.6%, then a Ti-B microalloy is added, the hardenability is improved, the O / N content is limited at the same time, then a two-stage refining process combining vacuum induction melting and electroslag remelting is adopted, the melting temperature, time and refining slag system components are regulated and controlled, and the hardness of the alloy is improved. The method comprises the following steps: preparing a copper plating solution through equipment, deeply removing harmful impurities such as S and P, promoting floating and size refinement of inclusions by applying an electromagnetic stirring technology, remarkably improving the purity of a metal matrix, thereby improving the purity of raw material smelting, proportioning the copper plating solution through the equipment, setting the parameters of the copper plating equipment to be 10-15A / dm in current density and 2-3mu m in plating thickness, and carrying out a copper plating process on a welding wire.

The invention discloses a cold-crack-resistant welding wire for thick-specification ultrahigh-strength steel and a welding method of the cold-crack-resistant welding wire, and belongs to the technical field of welding, a low-cost alloy system with Mn as a leading part and Cr as an auxiliary part is constructed, Mn is used for reducing the Ms point, the hardenability of Cr is improved, and the Ms point of weld metal is regulated and controlled to be in a low-temperature phase change interval of 100-150 DEG C; in the welding process, the inter-pass temperature is controlled to be higher than the Ms point all the time, all layers of welding beads are kept in the austenite state in the filling process, all the welding beads are uniformly cooled, low-temperature martensite phase transformation is synchronously generated, the situation that phase transformation of the welding beads which are firstly welded too early occurs, and consequently pressure stress relaxation is caused is avoided, and part of retained austenite is reserved is avoided. By means of the characteristics of a medium Mn alloy system, the common cold crack risk in thick plate high-restraint welding is effectively avoided, it is ensured that weld metal has the ultrahigh strength, meanwhile, the alloy cost is remarkably reduced, and therefore the technical bottleneck of thick ultrahigh-strength steel in the low-cost and efficient welding application aspect is broken through.

The invention relates to the technical field of black metal materials, in particular to saw blade steel with excellent repeated welding performance and a manufacturing method of the saw blade steel. The high-strength and high-toughness steel comprises the following chemical components in percentage by weight: 0.46%-0.55% of C, 0.3%-0.8% of Si, 0.4%-0.6% of Mn, less than or equal to 0.025% of P, less than or equal to 0.010% of S, 0.0010%-0.0020% of B, 0.10%-0.20% of Zr, 0.24%-0.35% of Co, 1.2%-1.5% of Co / (C / 10 + Mn / 5 + 60B) and the balance of Fe and inevitable impurities. According to the method, Zr, B and Co are added, and the processes of converter smelting, VD refining, continuous casting, slab heating, rolling and heat treatment are carried out, so that the steel strength and sufficient hardenability are guaranteed, the brittleness of a welding part and a heat affected zone is reduced, and the repeated welding performance of the saw blade steel is improved.

This invention provides a 590MPa grade solid welding wire, a laser-arc hybrid welding process, and a welded joint. The composition system of this invention is precisely adapted to the rapid heating and cooling thermal cycle characteristics and the burn-off law of key alloying elements in laser-arc hybrid welding of 590MPa grade marine engineering steel. By strictly controlling the content of highly hardenable elements such as C, Mn, Ni, and Mo, the formation of hardened structures in the weld metal is avoided. A certain amount of Ti element is added to provide nucleation points within the grains, directionally inducing the formation of a highly oriented and complex acicular ferrite matrix structure, thereby simultaneously improving strength and toughness through grain refinement. At the same time, an appropriate amount of V element is added to further improve the strength margin of the weld metal through microalloying. This welding wire has excellent welding processability and crack resistance, and can achieve room temperature welding without preheating or post-heating, providing material support for the high-quality and high-efficiency construction of marine engineering equipment.

This invention discloses a process for improving the hardenability of wind turbine main shafts during heat treatment, comprising the following steps: heating 42CrMo4 steel ingots to 1180~1220℃ for forging, with a forging ratio ≥4; air-cooling the forgings to 650~700℃ for the first time before loading them into a furnace, holding them at 300~350℃, then raising them to 640~660℃ for a second holding, with the holding time determined by the effective thickness × 1.5min / mm, followed by cooling to room temperature; vertically loading the forgings into tooling and heating them to 8... The surface is held at 40~860℃ for 1.2~1.5 min / mm (effective thickness × 1.2~1.5 min / mm) until the surface temperature drops to 780~800℃. Then, it is quenched in PAG solution within 3 minutes of quenching. After quenching, it is transferred to a tempering furnace and heated to 300℃ at a rate of ≤80℃ / h, held, and then heated to 540~580℃ at a rate of ≤100℃ / h, held for 2.0~2.5 min / mm (effective thickness × 2.0~2.5 min / mm). After tempering, it is cooled at a rate of ≤50℃ / h. This invention refines grains and carbides through forging and upsetting processes, controls pearlite cluster size through normalizing, and improves cooling uniformity through a density-layered dual-medium system during quenching. This method is suitable for improving the hardenability of large cross-sections in high-power wind turbine main shafts.

The application discloses a process for improving corner crack of 16MnCr5 steel hot-rolled blank, which comprises the steps of slow cooling before heating, heating, blooming rolling and slow cooling after rolling; the slow cooling before heating step: the blank is first slowly cooled for more than or equal to 72 hours; the heating step: the segmented heating control is adopted, the heating temperature of the first heating section is 850-950 DEG C, the heating temperature of the second heating section is 1110-1150 DEG C, the temperature of the soaking section is 1100-1180 DEG C, and the total heating time is controlled to be 4-5 hours; the blooming rolling step: nine passes of rolling are adopted, the reduction of the first four passes is 50-60 mm, the reduction of the middle four passes is 20-30 mm, and the reduction of the last pass is 10-20 mm; the hot-rolled blank is obtained; and the slow cooling after rolling step: the hot-rolled blank is slowly cooled for more than or equal to 72 hours. The application reduces or eliminates the generation of surface cracks of the wire rod, guarantees good hardenability of the product, and effectively improves the product quality.

The invention provides low-alloy structural steel 40MnB as well as a preparation method and application thereof. The low-alloy structural steel 40MnB comprises the following chemical components in percentage by weight: 0.37 to 0.44 percent of C, 1.10 to 1.40 percent of Mn, 0.17 to 0.37 percent of Si, less than or equal to 0.035 percent of P, less than or equal to 0.035 percent of S, less than or equal to 0.30 percent of Cr, less than or equal to 0.15 percent of Mo, less than or equal to 0.30 percent of Cu, less than or equal to 0.30 percent of Ni, 0.01 to 0.025 percent of Als, 0.0005 to 0.0035 percent of B, 0.01 to 0.04 percent of Ti and the balance of Fe and other inevitable impurities. The carbon content is increased to improve the strength and hardness of the steel, and meanwhile, the hardenability and strength of the steel are remarkably improved by accurately controlling the content of other alloy elements such as Mn, Si and B.

The invention belongs to the field of ferrous metallurgy, and particularly relates to high-temperature-resistant carburizing aluminum-free 20CrMnTi gear steel and a preparation method thereof, and the gear steel comprises the following chemical components in percentage by weight: 0.18%-0.23% of C, 0.17%-0.23% of Si, 0.95%-1.15% of Mn, 1%-1.35% of Cr, 0.04%-0.06% of Ti, less than or equal to 0.0008% of B, less than or equal to 0.020% of P, less than or equal to 0.015% of S, less than or equal to 0.010% of Alt, less than or equal to 0.005% of N and the balance of Fe and other inevitable impurities. The aluminum-free 20CrMnTi gear steel has the advantages that the three-in-one design thought of component design, precipitated phase regulation and control and process optimization is adopted, the aluminum-free 20CrMnTi gear steel is obtained, and the aluminum-free 20CrMnTi gear steel is refined in grain under high-temperature carburization, high in hardenability, low in cost and suitable for high-end transmission parts.

The invention belongs to the field of metal heat treatment intelligent manufacturing, and particularly relates to a large component hardening and tempering process closed-loop control method based on batch end quenching data correction, which comprises the following steps: carrying out a Jominy end quenching test on a batch of steel to be treated to obtain an end quenching hardness curve; the equivalent end quenching distance of the key position of the component is determined through an equivalent conversion model, and the actually measured initial hardness is read; constructing a tempering model containing an initial hardness genetic factor; correcting the sensitivity coefficient of the model by using single-point tempering test data of the end-quenched sample; reversely calculating a target tempering parameter according to the target hardness, calculating a tempering set temperature in combination with the production takt, and sending the tempering set temperature to the PLC temperature control system; and furnace temperature feedback is collected in real time during tempering, and the heat preservation time is dynamically adjusted to keep the target tempering parameter constant. Accurate control based on the real hardenability of the raw materials is achieved by introducing the actually measured initial hardness, and the consistency of the performance of the quenched and tempered large component is remarkably improved.

The application discloses a cold-rolled fine-blanking steel and a manufacturing method thereof. By optimizing the chemical composition and microstructure of the cold-rolled fine-blanking steel, the C content is controlled to be 0.30%-0.47%, the strength and hardness after quenching can be ensured, the Mn content is controlled to be 1.0%-1.5%, the hardenability of the steel can be improved, the hot brittleness can be prevented, and the forgeability and plasticity of the steel are improved; meanwhile, the number ratio of the spheroidal carbide is controlled to be greater than or equal to 90%, the average diameter of the spheroidal carbide is adjusted to be 0.5-0.8 mu m, any spheroidal carbide particle A is selected in a 1000 times metallographic graph of a cross section of the steel, another spheroidal carbide particle B exists in a circular area with the particle A as a center and a radius of 2 mu m, a sector with a center angle of 30 degrees and symmetrically distributed along the thickness direction of the steel is taken in the circular area, and the particle B does not fall into the sector, so that the size of the spheroidal carbide is smaller and the distribution of the spheroidal carbide is more uniform, and therefore the semi-punching limit depth can be increased.

The application provides a tool steel and a preparation method thereof. The tool steel comprises the following chemical components in percentage by mass: C: 0.50-0.59%, Si: 0.80-0.95%, Mn: 0.35-0.55%, Cr: 8.00-9.00%, W: 0.80-1.20%, Mo: 3.00-3.40%, V: 0.30-0.50%, Nb: 0.15-0.30%, Co: 0.18-0.38%, Ni: 0.15-0.35%, and the balance of Fe and impurities. The tool steel has excellent high strength, high toughness and red hardness through the design of alloy components, the increase of the content of Mo, the addition of Co and Ni elements, the design principle of multiple element combination, and the comprehensive consideration of the precipitation and growth mechanism of different element carbides in the solidification process.

The invention relates to a high-strength alloy steel rotor shaft forge piece and a manufacturing method. The high-strength alloy steel rotor shaft forge piece comprises, by mass, 0.3% of C, 0.057% of Si, 0.587% of Mn, 1.207% of Cr, 1.06% of Mo, 0.576% of Ni, 0.2610% of V, 0.0029% of P, 0.0011% of S and the balance iron. Or 0.3% of C, 0.059% of Si, 0.591% of Mn, 1.208% of Cr, 1.06% of Mo, 0.574% of Ni, 0.2727% of V, 0.0026% of P, 0.0010% of S and the balance of iron. The steel has the advantages of high temperature resistance, fatigue resistance, good corrosion resistance, high strength, high toughness and excellent hardenability.

The application discloses a manufacturing method of a hard surface lining plate which needs screw holes and deep hole machining. The method selects 42CrMo steel to forge the hard surface lining plate, and the hard surface lining plate is obtained through forging, normalizing, rough machining, flaw detection, quenching, semi-finishing, flaw detection, stabilization heat treatment, finishing and inspection in sequence. The hard surface layer is manufactured by using the hardenability and hardness gradient distribution of the steel. The finishing allowance is left on the deep hole side of the lining plate, and the high-hardness decarburized layer of the quenching and tempering heat treatment is machined away on the hard surface working side of the lining plate, so that the surface hardness of the lining plate is high and the hardness of the deep hole side is low, the service performance is ensured, and the machinability is ensured. The method overcomes the defects of the traditional hard surface lining plate screw hole and deep hole machining, reasonably arranges the machining allowance by using the hardenability and hardness gradient distribution change of the steel to avoid the hard surface layer, realizes the hard surface lining plate screw hole and deep hole machining, and ensures that the hard surface lining plate machining meets the process requirements.

The invention discloses gear steel, which is characterized in that except Fe and inevitable impurities, the gear steel comprises the following chemical components in percentage by mass: 0.25 to 0.30 percent of C, 0.03 to 0.30 percent of Si, 1.41 to 1.64 percent of Mn, 0.011 to 0.034 percent of S, 0.61 to 0.99 percent of Cr, 0.025 to 0.045 percent of Al, 0.006 to 0.014 percent of N, 0.002 to 0.029 percent of Nb, less than or equal to 0.30 percent of Ni, less than or equal to 0.20 percent of Cu, less than or equal to 0.10 percent of Mo, less than or equal to 0.015 percent of V, 0.011 to 0.039 percent of Ti, 0.0011 to 0.0040 percent of B and less than or equal to 0.02 percent of Sn. The gear steel is low in cost and has good high-temperature grain stability and hardenability. The invention further discloses a manufacturing method of the gear steel, round steel and a manufacturing method of the round steel.

The application relates to PG2 steel forged large-length-ratio thick-wall pipe material capable of bearing high temperature, high strength and high-low temperature impact and a heat treatment process. The material is PG2 steel, and the chemical components include the following according to mass percentage: C: 0.28-0.33%; Si: 0.15-0.35%; Mn: 0.75-0.95%; Cr: 1.80-2.10%; Ni: 3.00-3.50%; Mo: 1.20-1.40%; V: 0.20-0.35%; W: 0.20-0.50%; P: <=0.010%; S: <=0.005%; Cu: <=0.10%; Al: <=0.030%, and the balance is iron. Through sectional heating grain refinement and structure regulation technology, and in combination with the use of an inner hole cooling special tool installed at the bottom of a water tank, the PG2 steel forged large-length-ratio thick-wall pipe is uniformly and rapidly cooled, so that the mechanical properties and grain size of the PG2 steel forged large-length-ratio thick-wall pipe meet the design target, the material has high hardenability, the steel has normal temperature and 700 DEG C strength and low temperature impact toughness after quenching and tempering, and the requirements of high strength and high toughness are met.

This invention belongs to the field of metallurgical technology and relates to a production method for 22CrMoNbH heavy-duty niobium-containing gear steel. The method comprises three parts: chemical composition design, smelting production, and rolling production. The smelting process employs a four-stage process of "converter smelting – LF refining – RH vacuum degassing + continuous casting," precisely controlling impurity content and alloy uniformity. The rolling process utilizes "temperature-controlled rolling – slow cooling," optimizing microstructure and properties through dual electromagnetic stirring, temperature-controlled rolling, and slow cooling treatment. This invention, through niobium microalloying and synergistic process innovation, achieves a gear steel grain size ≥8 and a hardenability bandwidth ≤3HRC, significantly improving comprehensive mechanical properties and fatigue resistance. It can directly replace imported high-end heavy-duty gear steel, offering good production economics and is suitable for heavy-duty gear manufacturing in the automotive, heavy machinery, and other fields.

The application discloses a kind of low alloy high hardenability ultra-high strength steel and its preparation method, with mass percent, its chemical composition is C:0.29~0.33%, Mn:1.30~1.60%, Si:1.30~1.60%, Cr:1.10~1.40%, Ni:0.40~0.50%, Mo:0.30~0.50%, V:0.08~0.15%, Cu:≤0.20%, Ti:0.02~0.06%, B:0.001~0.005%, Al:0.01~0.06%, S:≤0.0060%, P:≤0.013%, the balance is Fe.The application is based on 30CrMnSiA, by trace addition alloying element Ni, Mo, V, Ti, B, Al, and cooperate production process to obtain the high-strength steel of strength 1600MPa grade;Strength is also obtained excellent hardenability while promoting, not only can be used as civil structural material, also can be applied to military industry.

Disclosed is a martensitic stainless steel with excellent hardenability through the control of a component system. The martensitic stainless steel with excellent hardenability comprises, in percent by weight (wt %), 0.01 to 0.1% of C, 0.05 to 0.1% of Si, 0.05 to 1.0 of Mn, 11.0 to 14.0% of Cr, 0.05 to 1.0% of Ni, 0.05 to 2.0% of Cu, to 0.08% of N, and the balance of Fe and inevitable impurities, and satisfies Formula (1).1.0≤Mn+Ni+Cu≤2.5,  Formula (1):wherein Mn, Ni, and Cu denote contents (wt %) of elements, respectively.

The invention discloses a high-strength steel plate with uniform structure property and yield strength of 590 MPa and a low-cost production method thereof. The steel plate is composed of the following elements: 0.135%-0.165% of C, 0.25%-0.35% of Si, 1.30%-1.40% of Mn, less than or equal to 0.020% of P, less than or equal to 0.003% of S, 0.015%-0.035% of Als, 0.010%-0.020% of Nb, 0.10%-0.25% of Cr, 0.010%-0.020% of Ti, 0.0008%-0.0018% of B, less than or equal to 0.0050% of N and the balance of Fe and inevitable impurities. The steel plate is strengthened mainly through conventional alloy elements such as C, Si and Mn and a small amount of microalloy elements such as Nb, Ti and B; on-line quenching and tempering processes are realized through control of a rolling compression ratio and an MULPIC cooling device, so that the problems of consideration of strength and toughness of the steel plate, thorough quenching of the steel plate and welding performance of the steel plate are solved; the thickness specification of the steel plate produced through the method ranges from 16 mm to 40 mm, the yield strength ranges from 638 MPa to 687 MPa, the tensile strength ranges from 725 MPa to 764 MPa, the ductility is larger than or equal to 20%, the-20 DEG C impact energy is larger than or equal to 180 J, the production process is simple, cost is low, market competitiveness is high, and prospects are wide.

The invention relates to a low-carbon equivalent extra-thick wind power steel plate with yield strength of 420 MPa and a manufacturing method thereof, and belongs to the field of metallurgy. According to the product, low-C economical hardenability elements added with Mn-Cr serve as an alloy system, V-Ti-Al fine grain strengthening is combined, addition of precious metal such as Ni / Cu / Mo / Nb is omitted, the carbon equivalent is controlled, and it is guaranteed that the steel plate is easy to weld. And the addition of the Si element is canceled, so that the surface quality is improved, and the fatigue aging of the wind power tower drum in the use process caused by low surface quality is avoided. And the microstructure is ferrite and pearlite. ReH is larger than or equal to 420 MPa, Rm is larger than or equal to 500 MPa, the ductility is larger than or equal to 19%,-50 DEG C Charpy V-type impact energy is larger than or equal to 31 J,-50 DEG C core Charpy V-type impact energy is larger than or equal to 31 J, and-10 DEG C CTOD value is larger than or equal to 0.27 mm.