37results about How to "Refined grain size" patented technology

The invention relates to a manufacturing method of a small-caliber nickel-copper alloy seamless heat exchange tube. The manufacturing method comprises the steps that S1, a UNS N04400 round steel material is subjected to peeling, PT inspection, shearing, centering, grinding, heating, perforating, water cooling and inspection; s2, a hot-punched blank is only cleaned, and inspection is conducted after point grinding is conducted after internal and external polishing; s3, the obtained pipe blank is subjected to first-pass intermediate product cold rolling, deoiling, straightening, pipe cutting, grinding, inspecting and cleaning; s4, second-pass intermediate product cold rolling, deoiling, heat treatment, straightening, pipe cutting, grinding, inspection and cleaning are conducted; S5, finished product cold rolling is conducted; s6, deoiling a finished product; s7, heat treatment of a finished product; s8, straightening a finished product; s9, performing ultrasonic vortex treatment, water pressure treatment and pipe cutting on a finished product; and S10, finished product surface inspection, size inspection, cleaning, mark spraying and finishing procedures are carried out. The method has the advantages of high one-time inspection qualification rate, yield and dimensional precision of products, good inner and outer surface quality, stable structure performance and high practicability.

The invention discloses a heat treatment-free die-casting aluminum alloy for a structural part. The heat treatment-free die-casting aluminum alloy comprises the following components in percentage by mass: 7.5%-11.5% of Si, less than or equal to 0.2% of Fe, 0.6%-1.2% of Mg, 0.05%-0.8% of Mn, 0.05%-0.4% of Cr, 0.03%-0.3% of Ta, 0.03%-0.3% of Nb, 0.03%-0.3% of Ni, 0.01%-0.12% of Ti, 0.03%-0.6% of Y, 0.03%-0.6% of Ce, 0.03%-0.6% of Er, 0.005%-0.05% of Sr and the balance of aluminum. The preparation method comprises the following steps: mixing and smelting an aluminum ingot, metal silicon, an aluminum-manganese intermediate alloy, an aluminum-chromium intermediate alloy, an aluminum-tantalum intermediate alloy, an aluminum-niobium intermediate alloy, an aluminum-nickel intermediate alloy, an aluminum-titanium intermediate alloy, an aluminum-yttrium intermediate alloy, an aluminum-cerium intermediate alloy and an aluminum-erbium intermediate alloy to obtain a melt I; adding a magnesium ingot into the melt I, smelting, introducing argon, refining to obtain molten aluminum, and casting to obtain an aluminum alloy ingot. The method is suitable for high-pressure casting forming to prepare force-bearing structural parts with complex shapes, can have good mechanical properties without heat treatment, and can be used for production of various parts required by new energy automobiles.

The invention relates to a forging heat treatment process for an ultralow-temperature high-strength austenitic stainless steel forge piece. The forging heat treatment process comprises the following steps that S1, raw materials are smelted; s2, performing high-temperature diffusion annealing on the raw materials; step S3, forging: (1) heating for the first time, lightly pressing and rounding a steel ingot at the final forging temperature of more than or equal to 950 DEG C; (2) secondary heating is conducted, the steel ingot is upset and drawn out, and the finish forging temperature is larger than or equal to 900 DEG C; (3) the third heating number is carried out, the steel ingot is upset and drawn out, and the finish forging temperature is larger than or equal to 850 DEG C; s4, heat treatment: (1) water cooling treatment after forging; (2) performing rough machining on the forge piece; (3) carrying out solution treatment, wherein the solution temperature range is 1050-1120 DEG C; the forging method has the advantages that the internal quality of the forge piece is improved, grains are refined, non-uniformity is eliminated, and the overall mechanical performance is improved by improving the components and the structure of the steel ingot and the forging process.

The invention discloses pipeline steel for carbon dioxide conveying and a production method thereof, and relates to the technical field of steel production, and the pipeline steel comprises the following chemical components in percentage by mass: 0.03%-0.07% of C, 0.10%-0.40% of Si, 1.00%-1.40% of Mn, less than or equal to 0.013% of P, less than or equal to 0.0020% of S, 0.030%-0.070% of Nb, less than or equal to 0.010% of V, 0.008%-0.030% of Ti, 0.20%-0.40% of Cr, 0.10%-0.30% of Ni, 0.05%-0.15% of Mo, less than or equal to 0.010% of Cu, 0.015%-0.055% of Al, less than or equal to 0.00050% of B, 0.0006%-0.0030% of Ca, less than or equal to According to the invention, a structure form taking bainite as a main component is realized, and the performance requirement of a product is met.

The low-alloy high-hardenability ultrahigh-strength steel comprises the following chemical components in percentage by mass: 0.29 to 0.33 percent of C, 1.30 to 1.60 percent of Mn, 1.30 to 1.60 percent of Si, 1.10 to 1.40 percent of Cr, 0.40 to 0.50 percent of Ni, 0.30 to 0.50 percent of Mo, 0.08 to 0.15 percent of V, less than or equal to 0.20 percent of Cu, 0.02 to 0.06 percent of Ti, 0.001 to 0.005 percent of B, 0.01 to 0.06 percent of Al, less than or equal to 0.0060 percent of S, less than or equal to 0.013 percent of P and the balance of Fe. On the basis of 30CrMnSiA, a trace amount of alloy elements Ni, Mo, V, Ti, B and Al are added, and the high-strength steel with the strength of 1600 MPa is obtained in cooperation with a production process; and meanwhile, excellent hardenability is obtained, and the steel can be used as a civil structural material and also can be suitable for the military industry.

The invention provides a preparation method of a high-performance aging-free high-carbon SWRH82B hot-rolled wire rod, and relates to the technical field of hot rolling, and the preparation method comprises the following steps: feeding a high-carbon SWRH82B steel billet into a heating furnace for heating; carrying out rough rolling on the heated high-carbon SWRH82B steel billet by adopting a large square billet large compression ratio rolling technology under heavy pressure; the high-carbon SWRH82B steel billet subjected to rough rolling is fed into a finishing mill to be subjected to finish rolling; the wire rod obtained after finish rolling is fed into an ultra-long air cooling line to be cooled through ultra-large air volume; the cooled wire rod is fed into a coiling device to be coiled; and the coiled wire rod is inspected and packaged, the high-performance aging-free high-carbon SWRH82B hot-rolled wire rod is obtained, a 134m ultra-long air cooling line and a 280000m / h ultra-large air volume fan are adopted for an ultra-long air cooling line, the cooling speed is increased, and therefore the supercooling degree of austenite is increased, nucleation of ferrite is promoted, ferrite grains are refined, pearlite is refined, and the high-performance aging-free high-carbon SWRH82B hot-rolled wire rod is obtained. And the lamellar spacing of pearlite and the thickness of cementite are reduced, so that the structure is easily converted into sorbite, and the product strength and the performance stability of the same circle are improved.

This invention relates to a forging method for improving the grain size of austenitic stainless steel pipes with nozzles. The method involves taking an electroslag ingot with a diameter of Φ1000–1200 mm, holding it at 1180±10℃ for 9–12 hours, and then drawing it to form a billet. After returning the billet to the furnace, the temperature is raised to 1200±10℃ and held for 7–8 hours. The billet is then upset with a flat upsetting cap, drawn into a flat square shape, and marked to form a flat square billet. This flat square billet is held at 1180±10℃ for 3–4 hours, drawn to lengthen both ends, and staggered to form a billet with a staggered nozzle. This staggered nozzle billet is held at 1150–1180±10℃ for 3–4 hours and then drawn, completing the forging process in one firing. This four-firing forging method for pipes with nozzles achieves a grain size ≥4 in the forging body, significantly improving the overall grain size of the austenitic stainless steel pipe with nozzle.

The invention relates to a preparation method of high-purity and high-toughness hot work die steel, which comprises the following steps: S1, electric furnace smelting; s2, refining in a ladle refining furnace; s3, refining in a vacuum refining furnace; s4, performing die casting on an electrode blank; s5, annealing the electrode blank; 6, electroslag remelting is conducted, specifically, an electrode blank is adopted, surface polishing is conducted, a calcium fluoride, aluminum oxide, magnesium oxide and silicon dioxide quaternary slag system is adopted for smelting, the starting point melting speed value of the electroslag smelting steady-state stage is 7-10 kg / min, the end point melting speed value of the electroslag smelting steady-state stage is 5.0-8.0 kg / min, an electroslag ingot is obtained, and then power-off furnace cooling is conducted for 80-100 min; s7, forging is conducted; s8, pretreatment after forging; and S9, solid solution and spheroidizing final treatment. According to the invention, on the basis of common hot work die steel H13, the prepared product has excellent high hardness, high purity and high toughness through fine adjustment of chemical components and special smelting, forging and heat treatment processes. The anti-cracking performance of a mold made of the material is greatly improved, the service life of the mold is prolonged, and meanwhile the use cost of the mold is greatly reduced.

The invention discloses a method for rapid diffusion bonding of a high-temperature titanium alloy through microwave sintering, which belongs to the technical field of titanium alloy welding and comprises the following steps: 1) pretreating a to-be-bonded surface of the high-temperature titanium alloy; 2) completely overlapping the two pretreated high-temperature titanium alloy test pieces to serve as a sample; 3) putting the sample into a microwave sintering furnace, and applying a pressure of 0.5-1.5 MPa above the sample; 4) heating the sample to a connection temperature of 970 DEG C in a mode of detecting the temperature of the sample in real time under a vacuum condition by using a microwave sintering furnace; and (5) heat preservation is conducted for 0.5 h to 1.5 h at the connection temperature of 970 DEG C, the high-temperature titanium alloy connector is cooled after heat preservation is completed, and the high-temperature titanium alloy diffusion connection connector is obtained. According to the method, the heating speed can reach 100 DEG C / min when high-temperature titanium alloy diffusion bonding is achieved, the machining efficiency is greatly improved, and an obtained high-temperature titanium alloy diffusion joint has the advantages of being stable in diffusion quality, small in joint grain structure, high in yield and the like.

The present application relates to the technical field of highway-railway dual-purpose transport equipment, in particular to a highway-railway dual-purpose steel rail double-frequency electric normalizing train, which comprises a vehicle body, a tool container and a mobile steel rail pressure-keeping double-frequency electric normalizing device are carried on the vehicle body; the vehicle body comprises a truck chassis assembly, a load-bearing frame and a hydraulic pump station are connected to the truck chassis assembly, and a set of telescopic hydraulic leg mechanisms are arranged at the front and rear ends of the truck chassis assembly respectively, and a wheel-rail running lifting mechanism is connected to the load-bearing frame; the present device is suitable for post-welding pressure-keeping double-frequency electric normalizing heat treatment operation of steel rail joints in seamless lines and urban rail transit. Furthermore, the device and the tool box are integrated and installed on a highway-railway dual-purpose vehicle, so that the working efficiency is improved, the on-and-off track operation and construction requirements of the device are facilitated, and the hoisting and carrying cost of the device can be greatly saved.

The present application relates to the technical field of titanium-based cathode roller, in particular to a large-size titanium-based cathode roller and a processing technology thereof, comprising the following processes: step one, taking a blank to carry out high-temperature blooming upsetting, punching, hole expanding, mandrel drawing, and obtaining a ring blank; step two, taking the ring blank obtained in step one to perform dressing and marking inspection; step three, taking the ring blank obtained in step two to perform turning, and obtaining a ring piece; step four, taking the ring piece obtained in step three to perform post-processing, and obtaining a cathode roller. The present application uses a new technology of forging-rolling combination to successfully produce a whole seamless ring piece at one time, which can effectively meet the requirements of the cathode roller on the morphology and mechanical properties at the microstructure level, and eliminate the occurrence of periodic bright band during the production of copper foil by the customer.

The invention relates to a manufacturing process of ultralow-temperature XM16 precipitation type martensitic stainless steel. The manufacturing process comprises the following steps that S1, raw materials are prepared, wherein C is smaller than or equal to 0.03%; less than or equal to 0.50% of Si; 0.50% or less of Mn; less than or equal to 0.015% of P; less than or equal to 0.015% of S; the alloy comprises the following components in percentage by weight: 8.0 to 9.5 percent of Ni, 11.5 to 12.5 percent of Cr, 2.0 to 2.5 percent of Cu, 1.0 to 1.4 percent of Ti and 0.15 to 0.50 percent of Mo; step S2, forging deformation: step 1, heating a blank to 550 + / -20 DEG C; 2, the blank is heated to 850 + / -20 DEG C; 3, the blank is heated to 1170 + / -10 DEG C; 4, deformation is conducted, and the finish forging temperature of the forge piece is controlled to be 830 + / -15 DEG C; step S3, solid solution: step 1, first-stage solid solution is carried out, and the solid solution temperature range is 880 + / -10 DEG C; 2, second-stage solid solution, wherein the solid solution temperature range is 880 + / -10 DEG C; and S4, aging is conducted, and the aging temperature range is 460-560 DEG C. The method has the beneficial effects that forging defects are eliminated, coarse grains and mixed grains in the structure are reduced, the impact toughness index of the precipitation type martensitic stainless steel at the ultralow temperature is improved through fine grain strengthening, and the forging quality is improved.

The invention relates to a forging processing method of a large cylindrical nuclear power forge piece, which relates to the technical field of nuclear power steel, and comprises the following steps: sequentially carrying out upsetting-drawing operation, punching, chambering, drawing to a blank size and solid solution heat treatment on a casting body to obtain the large cylindrical nuclear power forge piece; wherein the upsetting-drawing operation comprises upsetting and drawing which are sequentially carried out, the number of operation times is larger than or equal to 3, the total forging ratio is larger than or equal to 6, the initial forging temperature is 1180-1200 DEG C, and the final forging temperature is larger than or equal to 900 DEG C; and the temperature of the solid solution heat treatment is 1040-1060 DEG C. According to the forging machining method, specific upsetting-drawing operation and solid solution heat treatment are combined, the mechanical property of the obtained forge piece is improved, the use effect of the forge piece serving as a nuclear power workpiece can be improved, and for 0Cr18Ni10Ti stainless steel, the tensile strength is larger than or equal to 575 MPa at the temperature of 20 DEG C, the yield strength is larger than or equal to 250 MPa, and the ductility is larger than or equal to 50% at the temperature of 20 DEG C.

The application relates to the field of steel cords, in particular to a high-strength steel cord which comprises, in percentage by mass, 0.80-0.96% of carbon, 0.25-0.45% of manganese, 0.05-0.12% of vanadium, 0.15-0.3% of silicon, 0.08-0.15% of molybdenum, 0.02-0.05% of niobium, 0-0.08% of copper, 0-0.005% of aluminum, 0.15-0.3% of chromium, 0-0.06% of nickel, and the rest is iron; molybdenum and niobium are added in the steel cord to reduce the brittleness of the steel cord, reduce the wire breakage rate in the preparation process of the steel cord, and the carbon and vanadium contents are further improved, so that the strength of the steel cord is further improved, the high strength of the steel cord is ensured, and the excessively high wire breakage rate in the preparation process of the steel cord is prevented.

The invention relates to the technical field of anti-abrasion composite materials, in particular to a cast bionic metal ceramic plough share and a preparation method thereof.The preparation method comprises the following steps that a plough share precoated sand shell model with a scale structure is manufactured; mixing and kneading a water-based binder and alloy powder to prepare alloy powder paste, coating the soil contact part in the sand shell model of the plow share precoated sand with the alloy powder paste, and drying; the dried plow share precoated sand shell model and a casting system are subjected to box assembling, molten low-alloy structural steel is smelted, casting is conducted, and a composite plow share casting is obtained; according to the method, the metal ceramic alloy layer synthesized on the working surface of the plough share casting in situ is subjected to one-time casting forming, secondary machining is not needed, and the process is simple, rapid and efficient.

The invention discloses a high-strength heat-resistant aluminum alloy conductor which comprises the following components in percentage by mass: less than or equal to 0.15% of Fe, less than or equal to 0.15% of Si, 0.03-0.2% of Mo, 0.03-0.2% of Ta, 0.03-0.2% of Nb, 0.03-0.2% of Yb, 0.03-0.2% of Dy, 0.001-0.008% of B, less than or equal to 0.03% of other inevitable single impurity elements, less than or equal to 0.003% of the total amount of Mn, Cr and V, less than or equal to 0.15% of the total amount of the impurity elements and the balance of aluminum. The high-strength heat-resistant aluminum alloy conductor has high conductivity and excellent high-temperature mechanical properties, the tensile strength at the room temperature is larger than or equal to 160 MPa, the elongation at break is larger than or equal to 16%, the conductivity at the temperature of 20 DEG C is larger than or equal to 62% IACS, and the high-strength heat-resistant aluminum alloy conductor has high compressive creep resistance.

The invention relates to the technical field of metal material manufacturing, and particularly discloses a preparation method of an ultrahigh-strength C250 super-large-specification steel bar. The preparation method specifically comprises the following steps that high-temperature homogenization heat treatment is conducted on a steel ingot, wherein the heating temperature T of the steel ingot is 1200-1220 DEG C, and the heat preservation time t is larger than or equal to 40 h; the steel ingot is a steel ingot with the diameter of 810 mm; forging the steel ingot: pressing a clamp handle on the head of the steel ingot, and upsetting and drawing the steel ingot for four times to obtain a steel bar; the steel ingot deformation is larger than 50%, the last heating number forging starting temperature T is larger than or equal to 950 DEG C, and the final forging temperature T is larger than or equal to 800 DEG C; and performing heat treatment control on the oversized steel bar: performing air cooling on the forged steel bar until T is less than or equal to 200 DEG C, and performing solution treatment. According to the method, the problems of ultra-fine grain forging, structure homogenization control and the like of the C250 ultra-large-specification steel bar with the diameter being 375 mm are solved, and the metallurgical quality of the ultra-large-specification steel bar completely reaches the physical level of a small-specification steel bar.

The invention discloses a deep-sea acid-resistant pipeline steel and a production method thereof, which relate to the technical field of steel production. The steel has the following chemical composition and mass percentage: C: 0.010%-0.040%, Si: 0.10%-0.30%, Mn: 1.00%-1.40%, P≤0.013%, S≤0.0010%, Nb: 0.030%-0.070%, V: 0.30%-0.70%, Ti: 0.008%-0.030%, Cr: 0.10%-0.30%, Ni: 0.10%-0.30%, Mo≤0.50%, Cu: 0.10%-0.30%, B≤0.0005%, Mg: 0.0008%-0.0015%, Al: 0.015%-0.030%, and the balance is Fe and unavoidable impurities. Top and bottom combined blowing, converter smelting and vacuum degassing are adopted to obtain high-cleanliness molten steel. Continuous casting with large reduction technology and controlled rolling process are used to obtain a microstructure type dominated by blocky ferrite, which meets the requirements of deep-sea acid-resistant pipeline steel for service.

The invention belongs to the technical field of hard alloys, and particularly relates to a high-wear-resistance tungsten steel alloy and a preparation method thereof. The raw materials of the high-wear-resistance tungsten steel alloy comprise WC, Al-Sn-B nanometer oxide and a SiN / GO toughening phase, the tungsten steel alloy is designed to be of a gradient structure, the surface layer has hardness and wear resistance, the inner layer has good fracture toughness, WC is the main hard phase in the tungsten steel alloy, extremely high hardness and wear resistance are provided, and the high-wear-resistance tungsten steel alloy can be used for manufacturing the high-wear-resistance tungsten steel alloy. The Al-Sn-B nano oxide is added to form a sintering aid, so that the diffusion mass transfer process of WC in high-temperature solid-phase sintering is enhanced, the densification of the tungsten steel alloy is accelerated, and the fracture toughness of the tungsten steel alloy is improved by adding the SiN / GO toughening phase and utilizing a graphene toughening mechanism; the prepared high-wear-resistance tungsten steel alloy has excellent wear resistance and high-temperature oxidation resistance, and good toughness, strength and bending resistance.

The invention provides an ultrahigh heat conduction and corrosion resistance magnesium alloy and a preparation method thereof. The ultrahigh heat conduction and corrosion resistance magnesium alloy is an Mg-Zn-Ca-RE alloy system. Wherein RE is a rare earth element, the content of RE is 0.3-0.5 wt.%, the content of Zn is 4.5-5.5 wt.%, the content of Ca is 0.05-0.1 wt.%, and the balance is Mg and unremovable impurities. RE is at least one of La, Ce and Sm. According to the preparation principle, smelting, semi-continuous casting, annealing, extrusion cogging and graded rolling treatment are carried out, and the ultrahigh-heat-conduction corrosion-resistant magnesium alloy with high strength, high heat conduction performance and excellent corrosion resistance can be obtained.

The invention relates to the technical field of metal processing, and provides a heat exchange tube, a preparation method and application in a lead-bismuth fast reactor, the heat exchange tube comprises, by weight, 0.14-0.25% of C, 1.0-2.0% of Si, less than or equal to 1.0% of Mn, 10.0-12.0% of Cr, 1.0-2.0% of W, 0.15-0.30% of V, 0.10-0.20% of Ta, less than or equal to 0.01% of Ti, less than or equal to 0.01% of Al, less than or equal to 0.005% of P, less than or equal to 0.005% of S, less than or equal to 0.01% of Co, less than or equal to 0.01% of Ni, less than or equal to 0.01% of Cu, less than or equal to 0.005% of Mo, less than or equal to 0.005% of Nb, less than or equal to 0.002% of B The heat exchange tube is high in grain size, low in inclusion content and excellent in high-temperature strength, and meets the requirements of the heat exchange tube for the lead-bismuth fast reactor.

The invention discloses a seamless steel pipe for high-pressure boilers with high cleanliness and good toughness and a manufacturing method thereof, and belongs to the technical field of steel pipes for high-pressure boilers. The invention adopts converter smelting, LF+VD refining outside the furnace, continuous casting of square billets, cooling to room temperature and then entering a heating furnace, and continuous rolling to obtain a tube billet route, strictly controls steelmaking process parameters, obtains a high-clean seamless steel pipe for high-pressure boilers, makes the number and size of inclusions in the steel extremely small, and is cleaner near the inner and outer walls where cracks are easily generated, and then through optimized rolling process and heat treatment technology, effectively optimizes the metallographic structure phase composition, refines the grain size, and generates a structure ratio that can effectively improve the toughness of the steel pipe. The obtained steel pipe has a room temperature impact performance of more than 230J, an elongation of more than 25%, a yield strength of more than 480MPa, a tensile strength of more than 610MPa, excellent high-temperature tensile performance, and a yield strength of more than 320MPa at 550℃. The uniformity and stability of product performance are good, and it can be widely used in high-pressure boilers in different fields, and has broad market prospects.

The application discloses a titanium alloy special-shaped material production process for a mobile phone physical SIM card holder, and comprises the following steps: continuously hot-rolling titanium alloy wire rods to deform to corresponding sizes; performing acid pickling at least once before the last hot-rolling to remove the surface oxides of the wire rods; performing annealing treatment at least once after the last hot-rolling; performing cold-rolling and shape correction after the annealing to make the cross-sectional size of the product meet the final product size; performing annealing treatment at least once after the cold-rolling; performing acid pickling at least once after the cold-rolling and annealing treatment to remove the surface oxides of the wire rods; cutting after online straightening to form the final special-shaped material for the SIM card holder; and the multiple rolling and heat treatment mode solves the problem of difficult machining and forming of the titanium alloy, the shape of the wire rod is shaped through cold-rolling, the titanium alloy wire rod is shaped, and the mobile phone SIM card holder special-shaped material is formed through rolling.

The invention discloses a MoNb alloy target material and a preparation method thereof, and belongs to the technical field of target material preparation. Comprising the following steps that Mo powder and Nb powder are mixed in an inert atmosphere, and MoNb mixed powder is obtained; placing under a vacuum condition, and pre-sintering to obtain MoNb pre-sintered alloy powder; sheathing the MoNb pre-sintered alloy powder according to sheathing assembly, degassing, putting into a hot isostatic pressing sintering furnace, carrying out gradient heating to 1250-1400 DEG C, increasing the pressure to 110-160 MPa at a constant speed while heating, carrying out heat preservation calcination for 3-5 hours, cooling along with the furnace, and recovering the pressure to obtain a MoNb alloy target blank; and the MoNb alloy target blank is machined through a grinding machine, and then the MoNb alloy target with the qualified size is obtained. The prepared MoNb alloy target material is high in density, not prone to cracking, high in purity, uniform and fine in grain structure, good in conductivity and excellent in sputtering performance.

The application discloses a heat treatment process of low-alloy steel castings, and the heat treatment process of the low-alloy steel castings controls the chemical element content of the low-alloy steel castings reasonably, so that the strength of the steel castings is higher; the heating temperature in the heat treatment process is appropriately increased, and the holding time is prolonged, so that the structure transformation of the steel is sufficient, and the mechanical performance and the impact toughness are effectively improved. The heat treatment process adopts a process flow of preheating + normalizing + tempering + quenching + annealing, and compared with a traditional heat treatment process, the heat treatment process has the advantages that the grains are further refined and uniform, the grain size is maximally increased, and good structure conditions are prepared for subsequent heat treatment.

The invention discloses a CrMnTi gear steel with good low-temperature toughness and a production method thereof, belonging to the field of gear steel bar steel. The gear steel comprises: C: 0.18%-0.22%, Si: 0.20%-0.30%, Mn: 0.90%-1.10%, Cr: 1.00%-1.20%, Mo: 0.10%-0.20%, Ti: 0.040%-0.065%, W: 0.05%-0.15%; Ni: 0.05%-0.10%; Al: 0.020%-0.040%, B: 0.0020%-0.0040%, N: 0.010%-0.016%, Mg: 0.0035%-0.0065%, Ca: 0.0040%-0.0080%; the balance is Fe and unavoidable impurities. The gear steel of the invention can have good toughness at low temperatures.

The invention discloses an alloy material for an electromagnetic valve body and a preparation method, and the alloy material comprises the following components in percentage by weight: 0.010 to 0.025 percent of C, 0.50 to 1.50 percent of Si, 0.10 to 0.30 percent of Mn, 0.010 to 0.030 percent of P, 0.020 to 0.030 percent of S, 17.0 to 19.0 percent of Cr, 0.30 to 0.80 percent of Ni, 2.0 to 2.5 percent of Mo, 0.10 to 0.30 percent of Al, 0.02 to 0.05 percent of Ti and the balance of Fe. The alloy material is good in thermoplasticity, not prone to cracking in the deformation process and capable of being formed through forging and pressing after electric heating upsetting, the grain size of the material in the hot forming process is improved, and the coercive force, the elastic limit, the yield point, the tensile strength and other parameter indexes of the alloy material are all good.

This invention relates to a forging method for stepped gear shafts from continuously cast billets with diameters of φ600~φ785mm. The method involves loading the continuously cast billet into a heating furnace, holding it at 700~800℃, and then raising it to 1230℃±10℃. The billet is then upset with the tail end facing upwards using a concave upsetting plate, with an upsetting height-to-diameter ratio of 0.6~0.7. The billet is then drawn on an upper and lower flat plate, with a reduction of 13~18% per pass, and rotated 90° per pass. Finally, the billet is drawn on upper and lower flat anvils, with a reduction of 18~22%, and fed into the anvils at full capacity, ensuring at least one [unclear unit] per two anvils. With a 5% anvil loading, the anvil is rotated 90° per pass. A 3150-ton hydraulic press is used to upset the riser end with a concave upsetting plate, resulting in a height-to-diameter ratio of 0.6 to 0.8. The billet is drawn to be 20 to 30 mm larger than the maximum step diameter of the stepped gear shaft. After scoring, the billet is kept at a furnace temperature of 1030±10℃. The small steps at both ends are forged into finished products, and the large steps are forged into finished products within the range of 760℃ to 790℃. This improves the actual grain size and banded structure qualification rate of the stepped gear shaft, reduces the need for one normalizing step, and improves the low-magnification structure.

The present application relates to a kind of high-chromium high-nickel nitrogen-containing stainless steel forging billet quality control method, which can not only reduce forging heating fire times and save production cost, but also effectively improve the overall quality of the forging billet, suitable for the forging billet with outer diameter ≤350mm, first manufacturing intermediate billet with certain forging ratio + intermediate billet normalizing + air cooling + hydrogen annealing + forging billet surface temperature control + limited speed heating and step temperature holding + normalizing + temperature control cooling to promote microstructure transformation + high-temperature tempering and isothermal transformation composite process, which not only reduces forging heating fire times, saves production cost, but also effectively improves the overall quality of the forging billet.

The invention discloses a high-strength aluminum alloy profile for an automobile doorsill beam and a preparation method of the high-strength aluminum alloy profile, and belongs to the technical field of aluminum alloy preparation. The aluminum alloy profile comprises the following metal components in percentage by mass: 0.25%-0.35% of Si, 1.2%-1.6% of Mg, 0.2%-0.5% of Cu, 0.4%-0.6% of Mn, 0.1%-0.2% of Cr, less than or equal to 0.05% of Fe, 4.0%-4.5% of Zn, 1.0%-1.5% of Zr, 0.05%-0.1% of Ti and the balance of Al. The preparation method comprises the following steps of: feeding and smelting according to alloy components, casting an aluminum bar, homogenizing, extruding and forming, quenching on line, stretching, sawing, artificially aging, and detecting whether the mechanical property meets the requirement or not. According to the invention, alloy components are matched with a preparation process, so that the aluminum alloy section suitable for the threshold beam of the new energy automobile, of which the strength, corrosion resistance and the like meet requirements, is obtained.