1072 results about "Martensite" 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 a high-strength complex-phase hot-rolled wire rod for a 2200MPa-grade bridge cable and a manufacturing method of the high-strength complex-phase hot-rolled wire rod. After C-Si-Mn-Cr chemical components are rolled and spun into a wire rod, the wire rod is subjected to online molten salt critical quenching isothermal treatment, the wire rod is controlled to be subjected to front-section treatment and cooled at a cooling speed of greater than or equal to 38 DEG C / s, and enters a pearlite and martensite mixed phase region from an austenite state; the method comprises the following steps: firstly, carrying out heat treatment on austenite to promote transformation of part of austenite to sorbite and martensite, then carrying out post-treatment, reducing the circulation volume of molten salt, promoting transformation of austenite to pearlite, carrying out isothermal tempering, and finally carrying out roller way slow cooling, so as to prepare a hot-rolled wire rod of which the microstructure comprises a complex phase structure consisting of tempered pearlite, tempered sorbite, ferrite and tempered martensite, the composition system can be simplified, the deteriorated structure can be effectively controlled, complex-phase structure regulation and control and high-strength plastic performance matching are achieved, the tensile strength is 1568-1603 MPa, the percentage reduction of area is 29%-34%, and stable manufacturing of the bridge cable is facilitated.

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 cavitation-erosion-resistant martensite welding wire comprises powder and a welding skin, and the powder comprises, by mass, 20.0%-25.0% of Cr powder, 25.0%-30.0% of Ni powder, 5.0%-8.0% of Mo powder, 3.0%-5.0% of Nb powder, 3.0%-5.0% of W powder, 0.5%-1.0% of C powder, 4.0%-6.0% of B powder, 0.8%-1.0% of Y2O3 powder and the balance Fe powder. The welding wire is specially used for solving the problem of frequent cavitation failure of the turbine runner. The invention further discloses a preparation method of the cavitation-erosion-resistant martensite welding wire for the water turbine runner.

This high-pressure tank stores, inside a tank body, a mixed gas that contains natural gas and hydrogen, and that contains more than 2% hydrogen by volume. The tank body includes: a cylindrical part extending in a first direction; and a dome part connected to both ends of the cylindrical part in the first direction. The steel material constituting the tank body has a tensile strength TS of 850 MPa or higher, has a structure in which 95% or more by area ratio is tempered martensite, and includes carbides of 100 nm or less scattered in the metal structure as precipitates. The high-pressure tank has a strength of 11250 cycles or more in crack progress analysis, suppresses the influence of hydrogen embrittlement in metal, ensures gas storage capacity, and has a reduced weight.

The invention relates to the field of additive manufacturing, and discloses a dynamic phase change control additive ultrahigh-strength steel strengthening and toughening process which comprises the following steps: S1, constructing a phase change structure design target which comprises retained austenite distribution, a structure space structure and mechanical property requirements; s2, based on the phase change structure design target, establishing a free energy model taking a phase field variable as a core for representing a phase change driving behavior between austenite and martensite; s3, on the basis of the free energy model, constructing a multi-field partial differential control model coupling phase field evolution, element diffusion and heat conduction; and S4, in combination with the multi-field partial differential control model, determining an interface adsorption parameter, a diffusion coefficient and a thermophysical parameter based on experimental characterization data. According to the method, path parameters are optimized through a multi-field partial differential control model and tissue deviation feedback, and accurate control of the phase change tissue and dynamic closed-loop adjustment of the machining process are achieved.

The invention relates to a high-strength outer plate with excellent flanging forming performance and a preparation method, and belongs to the technical field of steel manufacturing. The high-strength outer plate comprises the following chemical components in percentage by mass: 0.05%-0.14% of C, 0.1%-0.4% of Si, 0.8%-1.4% of Mn, less than or equal to 0.01% of P, less than or equal to 0.005% of S, 0.5%-1.0% of Al, 0.01%-0.04% of Ti and a matrix element Fe, the microstructure of the high-strength outer plate comprises, by area ratio, 80%-90% of ferrite, 5%-15% of martensite and 2%-5% of retained austenite. By designing chemical components and microstructures, ferrite provides good elongation and deformability, martensite improves the strength of the material, and the element Ti realizes grain refinement by forming a precipitated phase, so that not only is the requirement on the waviness of the outer plate favorably realized, but also the hole expansion rate of the material can be improved. According to the obtained high-strength outer plate, the balance of various mechanical properties such as strength, ductility and hole expansion rate is achieved while the surface quality is met, and the forming and performance requirements of the outer plate are met.

The invention relates to a small-specification low-chromium high-carbon steel wire rod and a preparation method thereof. The diameter of the wire rod is # imgabs0. Chemical components of the wire rod comprise 0.79%-0.84% of C, 0.20%-0.30% of Si, 0.70%-0.90% of Mn, smaller than or equal to 0.020% of P, smaller than or equal to 0.020% of S, 0.18%-0.23% of Cr, smaller than or equal to 0.0040% of O, smaller than or equal to 0.0050% of N and the balance Fe and impurities. The production technology process mainly including KR molten iron pretreatment, converter smelting, LF refining furnace smelting, continuous casting, controlled rolling and controlled cooling and heat preservation channel slow cooling is adopted, the sorbite rate of the product reaches 90% or above through the measures of Cr micro-combination, the stelmor cooling technology and the like, the requirements of the high strength and the drawing technology of the wire rod are met, and the product quality is improved. The problems that in the wire rod production process, due to the fact that abnormal structure martensite appears, the strength is high, and brittle failure is caused in the wire rod drawing process are solved.

There is provided a panel including a steel plate that has a metal structure containing martensite, wherein the surface property aspect ratio Str of the steel plate in a flat part in a center-side portion of the panel is 0.50 to 1.00, and the surface roughness parameter Sa of the steel plate in an end part and the flat part in the center-side portion of the panel is 0.50 μm or below.

The invention relates to a high-strength complex-phase hot-rolled wire rod for a 2400 MPa bridge cable and a manufacturing method of the high-strength complex-phase hot-rolled wire rod. After high-carbon chemical components of Mo-Al-V are 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 the cooling speed of more than or equal to 35 DEG C / s, part of austenite structures are transformed into quenched martensite, and the quenched martensite structure is cooled at the cooling speed of more than or equal to 35 DEG C / s; the method comprises the following steps of: heating to the temperature of a sorbite phase region through rear-section molten salt, controlling unconverted austenite to be converted into sorbite, carrying out isothermal tempering, and finally, slowly cooling through a roller way to prepare a hot-rolled wire rod of which the microscopic structure comprises a complex-phase structure consisting of tempered martensite and tempered sorbite, so that the control of network carbide and other hard and brittle phase structures can be realized, and the service life of the hot-rolled wire rod is prolonged. According to the steel wire rod, the strength and the structure uniformity of the steel wire rod are improved, the material cost and good plasticity are both considered, the tensile strength is 1665-1705MPa, the percentage reduction of area is 26%-31%, the production efficiency is high, and stable production of 2400 MPa bridge cables is facilitated.

The invention discloses a manganese-copper alloy with high damping performance and a preparation method and application thereof. The preparation method comprises the steps that manganese-copper alloy powder is subjected to laser layer-by-layer scanning printing through a laser powder bed melting technology, and then the printed manganese-copper alloy is subjected to direct aging treatment. Obtaining a result parallel to the construction direction by regulating and controlling printing processes such as a laser scanning strategy, a layer thickness, a scanning interval and a substrate temperature; 001gt, 001gt; and the manganese-copper alloy is manufactured through strong texture additive manufacturing. Owing to lt; 001gt, 001gt; the oriented grains have more twin-crystal martensite variants, and twin-crystal martensite is easier to move under the action of external stress, so that the manganese-copper alloy has higher damping performance. The vibration reduction component is prepared by utilizing the special advantages of forming hollow, hollow-out, thin-wall and other complex structures of laser additive manufacturing, combination of manganese-copper damping alloy material vibration reduction and structure vibration reduction can be effectively achieved, and the manganese-copper damping alloy material can be widely applied to the field of vibration reduction and noise reduction of satellites, ships, rail transit, high-precision machine tools and other high-end equipment.

The invention relates to the technical field of high-hardness thick-specification high-wear-resistance steel plates, in particular to a high-hardness 30-80mm thick-specification flame-cutting-delayed-crack-free high-wear-resistance steel plate and a production method thereof. New flame cutting delayed crack preventing components and process design are adopted, the chemical components of the steel plate are mainly characterized by medium carbon, high silicon and niobium microalloying, and the wear-resistant steel plate with low impurity content, uniform and fine martensite and a certain amount of retained austenite structures is obtained after refining, continuous casting, controlled rolling and heat treatment. And formation and expansion of delayed cracks during flame cutting can be inhibited. And during flame cutting, thermal stress and structural stress formed in the cutting process of the thick steel plate are reduced through the cutting process of cutting with temperature and slow cooling with hot water after cutting, and the effect of no delayed crack after cutting is achieved. The surface hardness is larger than or equal to HB500, the tensile strength is larger than or equal to 1350 MPa, AKV at-40 DEG C is larger than or equal to 30 J, A is larger than or equal to 10%, retained austenite is 4%-6%, delayed cracks do not exist after flame cutting, and the flame cutting edge hardness is larger than or equal to HB460.

The invention discloses a heat treatment method of a high-strength and high-plasticity Ti-Nb-O titanium alloy, the titanium alloy comprises three elements of Ti, Nb and O, and the components comprise 13-22 wt% of Nb, 0.3-0.9 wt% of O and the balance Ti and inevitable impurities; through the design of a solid solution and aging heat treatment scheme, Nb and O elements in the structure are reasonably distributed in an alpha phase and a beta phase, finally, the alloy structure is controlled to contain the alpha phase and the beta phase, and a large number of nanometer martensite domains exist in the beta phase; the tensile strength of the alloy can reach 1100 MPa or above, the ductility is larger than 15%, and the elasticity modulus is smaller than 65 GPa. The high-strength and high-plasticity Ti-Nb-O titanium alloy has the characteristics of high strength, high plasticity, low elastic modulus, excellent biocompatibility and the like, is simple in component, reduces the preparation difficulty and cost, has important theoretical significance and engineering value, and is suitable for manufacturing biological implantation medical devices.

The application discloses a kind of martensitic age steel of additive manufacturing and preparation method thereof, the martensitic age steel, according to mass percentage, its composition is as follows: Ni 16~22%, Co0-5%, Mo 2~6%, Ti 0.2~2.5%, Al 0~1.5%, Re 0~0.3%, wherein Re is selected from at least one of Y or La, the balance is Fe and inevitable impurities.In the application, by reducing Co element, adjusting the ratio of Ni, Ti and Mo in the alloy, while adding a small amount of rare earth (Y and La) element, the alloy has higher M s Under the premise, the raw material cost of alloy powder and the preparation cost of alloy are greatly reduced, and the fine equiaxed grains and high-density nano precipitates formed after aging are formed by combining with the process parameter control of additive manufacturing, so that the mechanical properties of the martensitic age steel are greatly better than those of the traditional casting process.

The application discloses a kind of thick gauge 430 ferritic stainless steel laser weld low-temperature rollability processing method, comprising: using-1~‑2mm negative defocusing+8~10kW low-power laser welding, the grain of heat-affected zone is refined;NiCr-3 welding wire is preheated to 300~400℃ and carried out hot wire laser welding, reduces cooling rate;Weld is implemented 700 DEG C / 10-12 seconds short time induction annealing, decomposes martensite and releases residual stress;Weld is inducted to ≥50 DEG C before rolling and restores plasticity;Optimize five rack continuous rolling parameter, and the reduction of first rack is reduced to 15%-20%.The application is by welding-heat treatment-rolling whole process synergic control, makes weld low-temperature cracking rate from 2.6 times / month reduce to 1 times below, and-10 DEG C impact toughness is promoted to 22J, cup convexity qualification rate reaches 95%, and annual economic benefit is greatly improved, applicable to the thickness 3.0~8.0mm 430 stainless steel cold rolling production, solves the technical problem that thick gauge 430 stainless steel weld is easy to crack under low-temperature environment.

The invention belongs to the technical field of TC4 alloy additive manufacturing, and discloses an electron beam melting TC4 alloy isotropic optimization method based on staged temperature control HIP, which comprises the following steps of: depositing TC4 alloy powder along the normal direction of a substrate, and printing a part through an electron beam powder bed melting additive manufacturing technology; and then, staged temperature control hot isostatic pressing treatment is carried out on the printed part, and defects generated by printing are closed. According to the method, the hot isostatic pressing (HIP) technology is adopted, under the synergistic effect of the high temperature of 920 DEG C and the high pressure (Ar protection) of 150 MPa, the defects of air holes, incomplete fusion and the like in the TC4 alloy formed through EBM are eliminated through a plastic deformation and diffusion creep mechanism, and the density is remarkably improved. Meanwhile, a metastable martensite alpha'phase is promoted to be decomposed into an equilibrium-state alpha + beta double-phase structure in a high-temperature environment, and alpha-phase grains are moderately coarsened (the average size is increased to 3.12 microns from 1.71 microns).

The invention belongs to the technical field of metal material preparation, and relates to high-strength and high-plasticity cold-rolled medium manganese steel without a local deformation zone and a preparation method thereof.The preparation method comprises the steps that austenite-ferrite double-phase region annealing is conducted, and a medium manganese steel billet with the microstructure mainly composed of a manganese-rich austenite region and a manganese-poor ferrite region is obtained; carrying out cold rolling treatment on the annealed medium manganese steel billet to obtain a cold-rolled medium manganese steel billet body consisting of martensite and deformed ferrite; the cold-rolled medium manganese steel billet is rapidly heated to the austenite transformation temperature or above, and the medium manganese steel billet with the microstructure mainly composed of austenite with uneven manganese distribution is obtained; and the medium manganese steel billet is quenched to the room temperature, and a medium manganese steel finished product with the microstructure mainly composed of a manganese-rich austenite area and a manganese-poor martensite area is obtained. A martensite matrix and a small amount of metastable austenite in the microstructure ensure good plasticity and strength, a large amount of dislocation inhibits generation of a local deformation zone, and the uniform deformation capacity of the medium manganese steel is ensured.

The invention belongs to the technical field of research and development of fast neutron reactor jackets and structural materials, and particularly relates to a high-temperature-lead-bismuth-corrosion-resistant high-silicon-content ferrite / martensite steel ladle tube and a preparation method thereof. According to the mass percentage, the composition mainly comprises the following components: 0.16-0.24% of C; 0.4 to 0.8 percent of Mn; cr: 11.6% to 12.4%; 1.2 to 1.8 percent of W; 0.1 to 0.4 percent of Ta; 0.2 to 0.4 percent of V; 1.0%-1.8% of Si and Fe. The preparation method comprises the steps of vacuum induction and vacuum arc remelting. Carrying out homogenization treatment and forging; extruding and annealing; cold rolling and annealing; and performing normalizing and tempering treatment. Through an efficient short-flow process route and reasonable smelting, pipe machining deformation and heat treatment processes, the microscopic structure of the material is remarkably improved, then the mechanical property and high-temperature lead and bismuth corrosion resistance of the finished pipe are improved, and the use requirement of the lead and bismuth cooling fast reactor fuel assembly cladding material under the high-temperature working condition is met.

The invention discloses a heat treatment process of an alloy drill bit, which belongs to the field of alloy and comprises the following steps: S1, after the alloy drill bit is primarily machined and formed, carrying out vacuum pretreatment, heat preservation and heating; s2, the drill bit is rapidly transferred into a sectional temperature control carburizing furnace to be subjected to main carburizing treatment, the temperature is controlled between 930 DEG C and 960 DEG C, the carburizing time ranges from 3 hours to 4 hours, and the carburizing depth is controlled between 0.3 mm and 0.6 mm; s3, after carburizing is completed, subarea multi-speed cooling is carried out, quenching is carried out for 20 seconds at the temperature of 850 DEG C or above, controlled cooling is carried out for 60 seconds within the range of 550 DEG C to 650 DEG C, slow cooling is carried out for 80 seconds at the temperature of 200 DEG C or below, and a refined martensite complex phase structure is obtained; s4, after cooling is completed, double-section tempering treatment is carried out; and S5, performing ultrahigh-pressure static boriding diffusion treatment. The method has the beneficial effects that the processing uniformity, the structure stability, the wear resistance and the corrosion resistance of the alloy drill bit are effectively improved and the service life of the alloy drill bit is effectively prolonged by adopting staged temperature control, different cooling media and a directional quenching technology.

The invention provides high-strength and high-toughness steel based on laser rapid melting, and the alloy components of the high-strength and high-toughness steel comprise the following elements in percentage by mass: 0.1-0.3% of C, 0.1-2.6% of Mn, 0.1-1.5% of Ni, 0.1-4% of Mo, 1-4.5% of W, 0.1-1.2% of Si and the balance of Fe and inevitable impurity elements, in the impurity elements, P is less than or equal to 0.01%, and S is less than or equal to 0.02%; wherein the ratio of the sum of the mass percentages of Ni and Mn to the mass percentage of Si is not less than 1.572. Meanwhile, the invention further discloses an additive manufacturing method of the high-strength and high-toughness steel based on laser rapid melting. According to the high-strength and high-toughness steel, the influence of alloying elements on an Mf point and an Ac1 point is fully considered during design, it is ensured that all sedimentary structures are lath martensite, and the macrosegregation phenomenon in solidification structures is avoided through laser rapid melting; and then nanoscale film austenite is obtained on the two sides of the lath martensite through in-situ laser ultra-fast heat treatment or off-site infrared ultra-fast heat treatment, and the high yield strength of 1200 MPa and the ultrahigh Charpy V-shaped notch impact energy of 120 J are obtained.

The invention provides 1900MPa-grade cold-rolled medium manganese steel and a preparation method thereof, and relates to the technical field of high-strength and high-toughness automobile steel. The thickness of the 1900 MPa-grade cold-rolled medium manganese steel ranges from 1.3 mm to 1.5 mm, and the 1900 MPa-grade cold-rolled medium manganese steel is prepared from, by mass, 0.22%-0.25% of C, 6.5%-7.5% of Mn, 1.2%-1.7% of Al, 0.7%-0.9% of Si and Plt. 0.005%, Slt; 0.02% of the total weight; and the balance of Fe and inevitable impurities. The preparation method comprises the steps of raw material preparation, smelting, casting, forging, hot rolling, two-phase region annealing, tempering, cold rolling, quenching and baking treatment. According to the invention, by optimizing the two-phase region annealing process and the quenching temperature, ultrafine-grained ferrite, austenite and martensite microstructures are formed, the strength of the medium manganese steel is greatly improved, the enough percentage elongation after fracture is ensured, and the performance requirements of automobile anti-collision structural components are met.

The invention relates to the technical field of alloys, and discloses 2400MPa-grade ultrahigh-strength steel and a preparation method thereof. The 2400 MPa grade ultrahigh-strength steel comprises the following chemical components in percentage by mass: 0.3%-0.5% of C, 1.0%-2.5% of Si, 3.5%-5% of Mn, 0.2%-0.3% of V, 1%-3% of Ni, 0.02%-0.05% of Nb, 0.3%-0.5% of Mo, 0.5%-2% of Cr and the balance of Fe and inevitable impurities. The microstructure of the 2400 MPa grade ultra-high strength steel comprises martensite and austenite, the average grain size of the martensite ranges from 0.4 micrometer to 2.0 micrometers, and the ratio of the grain length axis to the grain length axis of the martensite is smaller than or equal to 1.6. The strength, plasticity and toughness of the 2400MPa-grade ultra-high-strength steel are improved, and the 2400MPa-grade ultra-high-strength steel has high strength, high plasticity and high toughness.

The invention discloses a high-strength and high-temperature titanium alloy and a preparation method, and belongs to the technical field of alloy materials, the high-strength and high-temperature titanium alloy comprises, by mass, 4.7%-6.5% of Al, 4.0%-6.0% of Sn, 2.5%-3.5% of Nb, 0.5%-2.0% of Mo, 0.2%-0.5% of Si, 0.05%-0.15% of B and the balance Ti and inevitable impurity elements; the yield strength of the high-temperature titanium alloy is larger than 1200 MPa, and meanwhile the ductility of the high-temperature titanium alloy is 11.38%. And the alloy has the tensile strength exceeding 1400 MPa when martensite is not subjected to heat treatment and complete decomposition, still has the ductility of 5%, and can further meet the requirement of current aerospace for the high strength of the high-temperature titanium alloy.

According to the low-strength high-formability austenitic stainless steel and the manufacturing method thereof, C + N is controlled to be smaller than or equal to 0.035%, the manganese content is controlled to be within 1.5%, the tin content is limited to be 0.01%-0.30%, the copper content is limited to be 2.4%-4.5%, and the tin-copper ratio is that (Sn / Cu) * 1000 is larger than or equal to 5 and smaller than or equal to 50, so that it is guaranteed that tin exerts the beneficial effects such as the corrosion resistance is improved, and the harm of tin segregation can be controlled to be at the low level; according to the finally obtained austenitic stainless steel, the yield strength is smaller than or equal to 160 Mpa, the tensile strength is smaller than or equal to 500 Mpa, the ductility is larger than or equal to 55%, the grain size grade is 6-8, edge cracks cannot occur during hot rolling, the martensite content of a cup drawing deformation part is 0.05% or below during large deformation machining, in other words, the austenite phase is still stable under the complex deformation condition, deformation cracks are avoided, and the service life of the austenitic stainless steel is prolonged. The comprehensive effects of high corrosion resistance, low strength and high forming machinability of the material are achieved.

The invention belongs to the technical field of steel forging, and particularly relates to martensite heat-resistant steel and a forging method. A forging process is optimized and improved, and after forging, furnace cooling of a forge piece is changed into the mode that the forge piece is rapidly cooled in air to 30-50 DEG C above the Ms transition point firstly, and then the forge piece is put into a furnace to be cooled along with the furnace. And coarse carbides generated during slow cooling of the material in a high-temperature area are avoided, then the material is put into a furnace to be cooled along with the furnace, and the forge piece is prevented from cracking during rapid cooling at the Ms point and below the Ms point. In the forge piece heat treatment process, the quenching charging mode is changed from furnace heating to temperature charging, the forge piece heating rate is increased, the superheat degree in the material austenitizing process is increased, the nucleation rate is promoted to be increased, and the grain size of the quenched forge piece is effectively increased. And the second tempering cooling mode is changed from air cooling to oil cooling. And the generation of second-class tempering brittleness in the tempering process is effectively avoided. A plurality of batches of forgings are produced according to the optimized process scheme, the impact performance tends to be stable, and the situation that the accidental impact performance is unqualified does not occur any more.

The invention provides solid solution strengthening type maraging stainless steel for a low-temperature environment and a preparation method, the stainless steel comprises the following component elements in percentage by weight: 10-12% of Cr, 8-10% of Ni, 6-7% of Co, 3-4% of Mo, 0.2-0.3% of Si, 0.15-0.3% of Mn, and a harmful element Clt; 0.023%, Slt; 0.0029%, Plt; 0.0021%, and the balance being Fe and inevitable impurities. According to the design concept of the solid solution strengthening maraging stainless steel alloy used in the low-temperature environment, solid solution strengthening is mainly used for replacing precipitation strengthening, high strength is guaranteed, and meanwhile the situation that a precipitated phase serves as a crack source to damage the low-temperature toughness and low-temperature fatigue performance of a material is avoided. The method mainly comprises the following steps: removing Ti to avoid the generation of a high-density Ni3Ti intermetallic compound precipitated phase, adding Si, Mo and other elements to reduce the precipitation rate of the Laves precipitated phase, and meanwhile, synergistically adding Co and Mo elements to improve the solid solution strengthening amount of the material and ensure the high strength of the material.

The application discloses a super-soft austenitic stainless steel and a preparation method thereof. The super-soft austenitic stainless steel is composed of carbon C, nitrogen N, silicon Si, manganese Mn, chromium Cr, nickel Ni, copper Cu and iron Fe. The mass percentage of each component in the super-soft austenitic stainless steel is as follows: C: 0.005%-0.02%, N: 0.05%-0.2%, Si: 0.01%-0.1%, Mn: 1.5%-6.5%, Cr: 15.5%-19.6%, Ni: 7.5%-13.5%, Cu: 1.8%-5.3%, and the balance is iron. The super-soft austenitic stainless steel has the characteristics of low tensile strength and hardness, low strain-induced martensite in the bending process, low crack initiation rate and low failure fracture.

The invention discloses a high-carbon rare-earth-containing wear-resistant steel ball and a manufacturing method thereof, and belongs to the field of metal materials. The wear-resistant steel ball comprises the following main components in percentage by weight: 0.6%-0.7% of C, 0.7%-0.9% of Si, 0.8%-1.0% of Mn, 0.6%-0.8% of Cr, 0.02%-0.04% of Al and 1t of P; 0.025%, S: lt; 0.025% of Fe, 0.01-0.05% of RE, less than or equal to 10ppm of melt O, and the balance of Fe and inevitable impurities. According to the rare-earth-containing wear-resistant steel ball, rare earth elements are introduced, one-heating forming is combined with a QP heat treatment process, a fine and uniform martensite and retained austenite structure on the surface is finally obtained, a martensite, retained austenite and pearlite mixed structure is formed in the core, the hardness of the surface of the steel ball is larger than or equal to 58 HRC, and the room-temperature unnotched ballistic energy is larger than or equal to 40 J. And high hardness, good impact toughness and wear resistance are shown.

The application relates to the technical field of austenitic stainless steel, in particular to high-strength and high-toughness austenitic stainless steel with large expansion and a preparation method thereof, alloy components of which are as follows in percentage by weight: C: 0.45-0.65 wt.%, Mn: 6.0-9.0 wt.%, Ni: 6.5-10.0 wt.%, Cr: 8.0-12.0 wt.%, Mo: 1.5-3.0 wt.%, V: 0.8-2.0 wt.%, Cu: 1.5-4.0 wt.%, Nb: 0.015-0.045 wt.% and Ti: 0.035-0.100 wt.%, and the balance is Fe. The thermal expansion coefficient of the obtained steel is superior to that of the prior art, the yield strength is greater than 950 MPa, the elongation after fracture is greater than 15%, no sensitization characteristics caused by grain boundary Cr carbide are generated, the steel is composed of pure FCC austenite with stable thermal mechanical properties, and no martensite and deformed austenite or austenite with high dislocation density appears.

The present invention provides a stainless steel material which has high strength, excellent overall corrosion resistance and stress corrosion cracking resistance in a supercritical corrosive environment, and excellent low temperature toughness in an extremely low temperature environment. A stainless steel material according to the present disclosure has the chemical composition set forth in the description, and has a microstructure in which Fn1 defined by formula (1) is 150.0 or more, Fn2 defined by formula (2) is 24.0 or more, and which is composed of 30.0-85.0% by volume of a ferrite phase and 0.1-40.0% by volume of a retained austenite phase, with the balance being made up of a martensite phase. The yield strength is 552-758 MPa, and the amount of precipitated V in the stainless steel material is 0.005-0.130 mass%.　(1): Fn1 = 576.5 - 2660.7 × C - 7.8 × Cr - 11.3 × Mo - 20.9 × Ni - 10.6 × Cu (2): Fn2 = 2 × Cr + 2 × Mo + 19 × V + 28 × N - 887 × C