929 results about "Pearlite" patented technology

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 relates to a hot-rolled wire rod for a 2200MPa bridge cable and a manufacturing method of the hot-rolled wire rod, a high-carbon V-containing chemical component design rolling production line is adopted, after the wire rod is spun into the wire rod at the spinning temperature of more than or equal to 920 DEG C, online molten salt rapid cooling isothermal treatment is carried out, the molten salt treatment time is controlled to be less than or equal to 300s, the wire rod is cooled at the cooling speed of more than or equal to 35 DEG C / s, and enters a sorbite phase region from an austenite state; according to the hot-rolled wire rod, a structure with sorbite as the main part is formed and subjected to isothermal weak tempering to remove stress, finally, roller way slow cooling is conducted, the hot-rolled wire rod with the microscopic structure comprising a mixed structure composed of weak tempered sorbite as the main part and ferrite and fused pearlite as the balance is prepared, the tensile strength can reach 1550-1590 MPa, the percentage reduction of area is 31%-36%, the mechanical property same-circle difference is smaller than or equal to 30 MPa, and the hot-rolled wire rod can be used for manufacturing the steel wire rod. The method is used in the application field of manufacturing of 2200MPa-grade ultrahigh-strength bridge cables and the like, the risk of wire breakage is reduced, and the strength grade of the bridge cables is improved.

The invention relates to a high-strength complex-phase hot-rolled wire rod for a 1960MPa-grade stranded wire and a manufacturing method of the high-strength complex-phase hot-rolled wire rod. After high-carbon components containing trace B are designed, rolled and spun into a wire rod, online molten salt rapid quenching treatment is carried out, and the wire rod is firstly subjected to front-section molten salt treatment, so that the wire rod is cooled at the cooling speed of greater than or equal to 36 DEG C / s and enters a bainite and pearlite mixed phase region from an austenite state; the method comprises the following steps: quenching a steel wire rod to form a structure mainly comprising quenched bainite and a sorbite structure, carrying out rear-section molten salt treatment on the steel wire rod, increasing the molten salt temperature, promoting isothermal tempering of the quenched bainite and the sorbite structure, and carrying out roller way slow cooling to prepare the hot-rolled steel wire rod of which the microscopic structure comprises a complex-phase structure consisting of tempered sorbite, tempered bainite and ferrite, the composition system can be simplified, the strength and plasticity matching and rapid production of the wire rod are considered, the tensile strength is 1330-1380 MPa, the percentage reduction of area is 35%-40%, and the wire breaking risk in the wire drawing and twisting process of the stranded wire steel can be reduced.

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

The invention relates to a high-strength complex-phase hot-rolled wire rod for a 2060MPa-grade stranded wire and a manufacturing method of the high-strength complex-phase hot-rolled wire rod. After high-carbon chemical components containing trace V are designed, rolled and spun into a wire rod, the wire rod is cooled at a cooling speed of more than or equal to 33 DEG C / s through on-line molten salt semi-quenching treatment, enters a bainite and pearlite mixed phase region from an austenite state, and is subjected to hot rolling and hot rolling at a cooling speed of more than or equal to 33 DEG C / s; the method comprises the following steps: quenching bainite and a sorbite structure to form a structure mainly comprising the quenched bainite and the sorbite structure, then carrying out isothermal tempering, and finally carrying out roller way slow cooling to prepare the hot-rolled wire rod of which the microscopic structure comprises a complex-phase structure consisting of tempered sorbite and tempered bainite, so that a component system can be simplified, the material cost can be reduced, network carbides can be effectively controlled, and meanwhile, the complex-phase structure can be regulated and controlled; the high strength and plasticity of the wire rod are matched, the tensile strength is 1390-1440 MPa, the percentage reduction of area is 32%-37%, and the steel wire rod is used for manufacturing 2060 MPa grade stranded wires and other application fields and is beneficial to downstream wire drawing and twisting processing.

The invention relates to a high-strength complex-phase hot-rolled wire rod for a 2230 MPa grade stranded wire and a manufacturing method of the high-strength complex-phase hot-rolled wire rod. After a Nb-containing high-carbon component is used for rolling and spinning at a spinning temperature to form a wire rod, online molten salt mixing quenching isothermal treatment is carried out, so that the wire rod is firstly subjected to front-section molten salt treatment and is cooled at a cooling speed of more than or equal to 35 DEG C / s, and enters a bainite and pearlite mixed phase region from an austenite state; the method comprises the following steps: firstly, carrying out heat treatment on austenite to promote part of austenite to be converted into bainite and sorbite, then carrying out later-section molten salt treatment, increasing the molten salt temperature, promoting unconverted retained austenite to be decomposed and converted into sorbite, carrying out isothermal tempering, and finally, carrying out roller way slow cooling, so as to prepare the hot-rolled wire rod of which the microscopic structure comprises a complex-phase structure consisting of tempered bainite and tempered sorbite, the drawing and hardening capacity can be improved, the production efficiency is considered, the tensile strength is 1522-1572 MPa, and the percentage reduction of area is 29%-34%, so that off-line heat treatment is avoided, and the wire breaking risk and cost of stranded wire manufacturing are reduced.

The cold heading wire rod comprises the following components in percentage by mass: 0.20%-0.26% of C, less than or equal to 0.35% of Si, 1.2%-1.6% of Mn, less than or equal to 0.02% of P, less than or equal to 0.005% of S, 0.04%-0.14% of V, 0.02%-0.10% of Nb, less than or equal to 0.2% of Cr, less than or equal to 0.1% of Ni, 0.02%-0.06% of Al and the balance of Fe and inevitable impurities, the V + Nb is greater than or equal to 0.09%, the C / 4 + Si + Mn / 2 + Cr / 2 + 2Ni is greater than or equal to 1.1% and less than or equal to 1.3%, the F + P is greater than or equal to 95%, the F grain size is greater than or equal to grade 12, the longitudinal pearlite strip The steel plate prepared by the method does not crack at 1 / 5 of a hot rolling state, can meet the requirements of a user on strength and plasticity of cold heading forming after 5-50% of cold drawing deformation, and can meet the requirements of a 10.9-grade high-strength fastener on fatigue and delayed fracture resistance at the same time.

The invention belongs to the field of steel rail manufacturing, and discloses a method for improving the impact toughness matching performance of a dissimilar material steel rail welding joint. The method comprises the following steps: carrying out first-stage cooling on a welding joint formed by welding the eutectoid pearlite steel rail and the bainite steel rail; carrying out full-section normalizing heating on the welded joint; the welding joint is subjected to second-stage cooling, a heat affected zone on one side of the heat treatment type eutectoid pearlite steel rail is cooled to 350-400 DEG C at the cooling rate of 4.0-7.0 DEG C / s, and a heat affected zone on one side of the hot rolling type bainite steel rail is cooled to 290-315 DEG C at the cooling rate of 2.0-3.0 DEG C / s; the welding joint is heated to a bainite transformation temperature interval for isothermal treatment; and naturally cooling the welding joint in an air environment. According to the method provided by the invention, the room-temperature impact toughness of the heat affected zone on one side of the hot-rolled bainite steel rail can be obviously improved, so that the performance of the hot-rolled bainite steel rail is better matched with that of a hot-rolled bainite steel rail base material.

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 steel plates for automobile frames, in particular to a 510MPa-grade green clean-surface steel plate for an automobile frame and a manufacturing method of the 510MPa-grade green clean-surface steel plate. The tensile strength of the steel plate reaches the 510 MPa grade or above, the surface cleanliness of the steel plate reaches the 3.0 grade, and the steel plate is composed of, by weight, 0.06%-0.08% of C, 0.05%-0.15% of Si, 1.40%-1.55% of Mn, 0.015%-0.045% of Als, 0.015%-0.030% of Nb, 0.015%-0.030% of Ti, smaller than or equal to 0.020% of P, smaller than or equal to 0.010% of S and the balance Fe and inevitable impurities. The structure of the finished steel plate is composed of ferrite and pearlite. The alloy has the characteristics of excellent processability and corrosion resistance, high surface quality, zero pollution and low cost.

The invention relates to a hot-rolled wire rod for a 2400 MPa bridge cable and a manufacturing method of the hot-rolled wire rod, after high-carbon components of Cr-Mo-V are rolled and spun into a wire rod, the wire rod is subjected to online molten salt rapid cooling isothermal treatment, so that the wire rod is cooled at the cooling speed of more than or equal to 32 DEG C / s and enters a sorbite phase region from an austenite state to form a structure taking sorbite as a main part, and precipitation and growth of carbides are controlled; and finally, roller way slow cooling is conducted, the hot-rolled wire rod with the microscopic structure comprising a mixed structure composed of tempered sorbite, ferrite and fused pearlite is prepared, the strength and plasticity matching performance of the wire rod can be improved, the mechanical property fluctuation can be reduced, the tensile strength can reach 1640-1680 MPa, the percentage reduction of area can reach 27%-32%, the mechanical property same-circle difference is smaller than or equal to 45 MPa, and the tensile strength of the wire rod can reach 1640-1680 MPa, the percentage reduction of area can reach 27%-32%, and the mechanical property same-circle difference is smaller than or equal to 45 MPa. And rapid and stable production is facilitated, the method is used for manufacturing the 2400 MPa bridge cable, and the wire breaking risk can be reduced easily.

The invention relates to the technical field of nodular cast iron, in particular to a silicon-molybdenum-chromium-nickel-niobium nodular cast iron material and a preparation method thereof. The material comprises the following chemical components in percentage by mass: 3.0%-3.5% of carbon, 4.3%-4.7% of silicon, 0.1%-0.3% of manganese, less than or equal to 0.05% of phosphorus, less than or equal to 0.02% of sulfur, 0.7%-1.0% of molybdenum, 0.6%-0.8% of chromium, 0.4%-0.7% of nickel, 0.3%-0.6% of niobium, 0.03%-0.06% of magnesium, 0.05%-0.1% of rare earth, 0.006%-0.012% of antimony and the balance of iron. The preparation method comprises the steps of smelting, first-time spheroidizing and inoculation, second-time spheroidizing, second-time inoculation and heat treatment in sequence. According to the obtained nodular cast iron material, the form of graphite and the number of graphite nodules are improved, carbon elements are separated out as many as possible in the form of high-carbon phase-spheroidal graphite, generation of pearlite is reduced, and the mechanical strength and high-temperature resistance of nodular cast iron are improved.

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

This hot-rolled steel sheet has a predetermined chemical composition, a microstructure includes 80% or more of tempered martensite by a volume percentage and a remainder consisting of one or more of ferrite, pearlite, bainite, fresh martensite, and residual austenite, the tempered martensite includes 5×109 pieces / mm3 or more of precipitates containing Ti and having an equivalent circle diameter of 5 nm or less per unit volume, in a surface layer region that is a range from a surface to a 1 / 10 position of a sheet thickness, a sum of an average pole density of a crystal orientation group consisting of {211}<111> to {111}<112> and a pole density in a crystal orientation of {110}<001> is 6.0 or less, and a tensile strength is 980 MPa or more.

The invention relates to the technical field of manufacturing of engineering machinery parts, and discloses an engineering machinery driving wheel made of a medium carbon alloy cast steel material. The invention also discloses a preparation process of the engineering machinery driving wheel material, which comprises the following steps: S1, casting treatment: melting the medium carbon alloy steel material, and casting into a driving wheel blank; s2, normalizing heat treatment: carrying out normalizing heat treatment on the driving wheel blank; s3, rough machining treatment; s4, quenching treatment: carrying out induction quenching treatment; and S5, finish machining treatment. The synergistic effect of alloy elements in a medium carbon alloy cast steel material is combined with an optimized air cooling process, so that the cast steel is normalized to obtain a uniform structure which mainly contains superfine pearlite and contains extremely little ferrite, the matrix hardness is stable, and the requirement of a high-performance driving wheel is completely met; after the process route is improved, tempering and shot blasting and flaw detection procedures after tempering are canceled; the technological process is greatly shortened, material turnover is reduced, and the production efficiency is improved.

The invention discloses a production method for online softening of a high-strength cold heading steel wire rod. The wire rod comprises the following chemical components in percentage by mass: 0.33-0.38% of C, 0.15-0.35% of Si, 0.60-0.90% of Mn, less than or equal to 0.025% of P, less than or equal to 0.020% of S, 0.9-1.20% of Cr, 0.15-0.30% of Mo, more than or equal to 0.02% of Al and the balance of Fe and inevitable impurities. The key process steps comprise a rolling procedure and a heat preservation vestibule online softening procedure. According to the on-line softening production method for the high-strength cold heading steel wire rod, the phase change rule of the high-strength cold heading steel wire rod is mastered through thermal simulation and research, and the high-strength cold heading steel wire rod is obtained under the high-speed wire rod equipment conditions of a reducing and sizing unit, a short heat collection coil Stelmor air cooling line and a heat preservation vestibule. And the pearlite and ferritic structure wire rod with the tensile strength being smaller than or equal to 820 MPa in the hot rolling state and refined and uniform grains is obtained, the softening annealing procedure before rough drawing of a fastener user is omitted, rough drawing production with the large reducing rate can be achieved, and energy consumption is reduced.

The invention relates to a high-strength complex-phase hot-rolled wire rod for a 2260MPa-grade stranded wire and a manufacturing method of the high-strength complex-phase hot-rolled wire rod, after the high-carbon component design of C-Si-Mn-Cr-V-Nb-V is rolled and spun into a wire rod, the wire rod is subjected to online molten salt mixed quenching isothermal treatment, so that the wire rod is subjected to front-section molten salt treatment to be quickly cooled, enters a bainite and pearlite mixed phase region from an austenite state, and is subjected to hot rolling and hot rolling to form the high-strength complex-phase hot-rolled wire rod. The method comprises the following steps: carrying out first-stage molten salt treatment on austenite to promote transformation of part of austenite to bainite and sorbite, then carrying out later-stage molten salt treatment to increase the molten salt temperature, promoting decomposition and transformation of untransformed retained austenite into sorbite, carrying out isothermal tempering, and finally carrying out slow cooling through a roller way, a hot-rolled wire rod with a microscopic structure comprising a complex-phase structure composed of tempered bainite, tempered sorbite and ferrite is manufactured, the tensile strength is 1547-1597 MPa, and the percentage reduction of area is 27%-32%, so that when a high-strength stranded wire is manufactured, off-line heat treatment is not needed, the drawing pass number is reduced, and the wire breaking risk is reduced.

The invention discloses a hot-rolled pickled steel plate for a saw blade and a manufacturing method of the hot-rolled pickled steel plate. The technical problems that existing high-carbon and high-manganese steel with the thickness of 2.5-7.0 mm for the saw blade is prone to segregation, poor in structure uniformity and thick and large in pearlite structure are mainly solved. According to the technical scheme, the hot-rolled pickled steel plate for the saw blade comprises the following chemical components in percentage by weight: 0.75%-0.85% of C, 0.20%-0.50% of Si, 0.20%-0.50% of Mn, less than or equal to 0.020% of P, less than or equal to 0.005% of S, 0.01%-0.02% of Al, less than or equal to 0.0060% of N, 0.4%-0.8% of Cr, 0.18%-0.28% of V and the balance of Fe and inevitable impurity elements. The metallographic structure of the hot-rolled pickled steel plate is superfine pearlite with the interlamellar spacing of 0.4-0.8 mu m, and the hot-rolled pickled steel plate is used for production of circular saw webs, chain saws, frame saws and the like.

An embodiment of the present invention provides a steel material, for a pressure vessel, comprising, in weight %, 0.06-0.25% of carbon (C), 0.05-0.50% of silicon (Si), 1.0-2.0% of manganese (Mn), 0.005-0.40% of aluminum (Al), 0.010% or less of phosphorus (P), 0.0010% or less of sulfur (S), 0.001-0.03% of niobium (Nb), 0.001-0.03% of vanadium (V), 0.001-0.03% of titanium (Ti), 0.01-0.20% of chromium (Cr), 0.05-0.15% of molybdenum (Mo), 0.01-0.50% of copper (Cu), 0.05-0.50% of nickel (Ni), 0.0005-0.0050% of magnesium (Mg), 0.0005-0.0050% of calcium (Ca), 0.0020% or less of oxygen (O), and the remainder being Fe and other unavoidable impurities. A microstructure comprises in terms of area fraction 30% or less of pearlite and the remainder being ferrite. A non-metallic inclusion contains Mg—Al—Ca—O composite oxide.

The invention relates to the field of screw forming, and discloses a screw cold heading forming process which is characterized by comprising the following steps: step 1, wire preparation and surface pretreatment: based on the requirement of screw forming on the surface quality of raw materials, a metal wire is treated by adopting a mechanical wiredrawing and chemical phosphating and saponifying composite process, and the surface of the metal wire is treated; surface oxide skin is removed, a lubricating film layer is formed, and the forming flowability and the service life of the die in the subsequent cold heading process are effectively improved. A raw material is subjected to spheroidizing annealing treatment in a continuous spheroidizing annealing furnace, internal pearlite is converted into spherical cementite, the ductility and deformation uniformity of the material are improved, then a continuous wire drawing machine is adopted for multi-stage drawing diameter reduction, a three-stage chemical phosphating-saponification treatment process is matched, a low-friction and high-adhesion lubricating film layer is formed, and the service life of the lubricating film layer is prolonged. And a stable material basis and a lubricating environment are provided for the subsequent cold heading process, so that the problems that the friction resistance generated in the forming process of a screw material is large, and a mold is quickly worn are solved.

A rail including a predetermined chemical composition is provided, in which 90 area % or greater of a metallographic structure in a cross section of a rail web portion is a pearlite structure, a minimum value of a hardness in the cross section of the rail web portion is Hv 300 or greater, and a difference between a maximum value and the minimum value of the hardness in the cross section of the rail web portion is Hv 40 or less.

The invention belongs to the technical field of nodular cast iron preparation, and discloses nodular cast iron, a casting and a preparation method of the nodular cast iron, and the nodular cast iron comprises the following chemical components in percentage by weight: 3.68 to 3.75 percent of C, 2.35 to 2.45 percent of Si, less than or equal to 0.10 percent of Mn, 0.010 to 0.030 percent of P, 0.008 to 0.015 percent of S, less than or equal to 0.010 percent of Ti, 0.0050 to 0.0060 percent of Sb, 0.050 to 0.060 percent of Sn, 0.0065 to 0.0080 percent of La, 0.035 to 0.045 percent of Mg and the balance of Fe and unremovable impurities. The preparation method of the nodular cast iron comprises the following steps that 1, raw materials are smelted to obtain molten iron; 2, slag pulling is conducted on the molten iron, and impurities are removed; 3, the molten iron obtained in the step 2 is poured into an electric furnace, silicon carbide accounting for 0.20-0.30% of the weight of the molten iron is added in the process, and then spheroidizing inoculation treatment is conducted; and 4, pouring is conducted, nodular cast iron is obtained, and stream inoculation treatment is conducted in the pouring process. By limiting the composition and the dosage of the nodular cast iron and controlling the adding time and the dosage of silicon carbide in the preparation process, pearlites in the nodular cast iron can be uniformly distributed, and the number of the pearlites is stably controlled between 35% and 45%.

The invention provides 500MPa-grade mining anti-corrosion anchor rod steel and a production method thereof. The 500MPa-grade mining anti-corrosion anchor rod steel comprises the following components: 0.09 to 0.12 percent of C, 0.60 to 0.70 percent of Si, 0.90 to 1.00 percent of Mn, 1.34 to 1.40 percent of Cr, 0.070 to 0.080 percent of V, 0.70 to 0.80 percent of Ni, less than or equal to 0.025 percent of P, less than or equal to 0.010 percent of S and the balance of Fe and inevitable impurities. Compared with the prior art, the production method is simple, the component design is reasonable, the quality of a casting blank can be improved, the strength and impact performance of a rolled material are guaranteed, meanwhile, the stress corrosion crack sensitivity is reduced, and the corrosion resistance is improved. The obtained microscopic structures of the product are ferrite and pearlite structures, bainite and other hardening phases do not exist, good matching of strength, plasticity and corrosion resistance is achieved, the corrosion-resistant anchor rod product completely meets the use requirements in the mine environment, and the product quality is improved.

The invention relates to the field of metal material casting, and discloses a production method of green sand as-cast high-plasticity nodular cast iron QT800-5, which comprises the following steps: preparing pig iron, waste steel and foundry returns, and using auxiliary materials such as a silicon carbide pretreating agent, a high-temperature graphitization carburant, a rare earth magnesium silicon iron nodulizing agent, a silicon barium nucleating agent and a silicon strontium nucleating agent to prepare the green sand as-cast high-plasticity nodular cast iron QT800-5. The purity and component stability of molten iron are ensured; in the smelting process, purification and adjustment are carried out through temperature control and segmented addition of auxiliary materials, then spheroidizing is carried out through a pouring method, and the microscopic structure of a casting is optimized through ladle-to-ladle inoculation and stream inoculation; the final casting has excellent mechanical properties including the tensile strength larger than or equal to 800 MPa, the yield strength larger than or equal to 480 MPa, the elongation larger than or equal to 5% and the matrix pearlite content larger than or equal to 80%. The production process disclosed by the invention is simplified, is suitable for large-scale industrial production, and has a wide application prospect in lightweight application requiring high-strength and high-plasticity materials.

The invention discloses medium-carbon round steel for cold extrusion, which contains Fe and inevitable impurities, and further contains the following chemical elements in percentage by mass: 0.36 to 0.43 percent of C, 0.1 to 0.4 percent of Si, 0.6 to 1 percent of Mn, 0.6 to 1 percent of Cr, 0.2 to 0.4 percent of Mo, 1.4 to 1.7 percent of Ni, 0.02 to 0.04 percent of Al, 0.008 to 0.015 percent of N and the balance of Fe. And after annealing, the microstructure is flaky pearlite and spherical pearlite. Correspondingly, the invention also discloses a manufacturing method of the medium-carbon round steel for cold extrusion, which comprises the following steps: (1) smelting and casting; (2) heating; (3) forging or rolling; (4) stepped annealing; and (5) surface treatment.

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 invention discloses a heat treatment process for relieving large-size carbides of a 17CrNiMo6 large-modulus gear. The heat treatment process comprises the following steps: a) first-time heating: heating a workpiece to a carburizing temperature in a gradient heating manner; b) heat-preservation carburizing: carburizing the workpiece by adopting multi-section pulse carbon potential; c) cooling after carburization: carrying out furnace gradient cooling on the workpiece to 660 + / -5 DEG C; d) heat preservation transformation: the workpiece is subjected to heat preservation at 660 + / -5 DEG C for a period of time, so that dispersed cementite precipitation and pearlite transformation are fully carried out; e) heating and preserving heat for the second time: heating the workpiece to 820 + / -5 DEG C, and preserving heat for austenite transformation; and f) quenching. Therefore, large-size carbides in a gear structure after heat treatment can be reduced, martensite needles in a quenched workpiece are effectively promoted to be smaller and thinner, the content of retained austenite is low, the metallographic structure of the workpiece is guaranteed, the use performance of parts is met, and the heat treatment method is particularly suitable for heat treatment of large-modulus gears.

Provided is a steel sheet characterized by having a prescribed chemical composition and in that: the metal structure thereof contains, in terms of area%, 10-40% of ferrite, 60-90% of martensite, 0-10% of bainite, and a total of 0-5% of at least one among pearlite and retained austenite; and when a 150 μm × 150 μm region at a position at 1 / 4 of the sheet thickness in a cross section perpendicular to the sheet surface is equally divided into nine regions, the number density of ferrite in each of the divided regions is calculated, and the average value thereof is indicated by Nαm, the difference in the number density of ferrite between divided regions adjacent to each other in the sheet thickness direction is Nαm × 0.60 or less in all cases. Also provided are a component including the steel sheet, and a method for manufacturing the steel sheet.

The invention relates to large-thickness high-homogeneity polar region ship low-temperature steel and a preparation method thereof. The steel plate comprises the following chemical components in percentage by weight: 0.06%-0.12% of C, 0.15%-0.35% of Si, 1.10%-1.40% of Mn, less than or equal to 0.008% of P, less than or equal to 0.008% of S, 0.020%-0.050% of Nb, 0.020%-0.040% of Al, 0.010%-0.020% of Ti, 0.04%-0.08% of residual element Mo and the balance of Fe and inevitable impurity elements. The carbon equivalent CEV is less than or equal to 0.38%, and the cold crack sensitivity index Pcm is less than or equal to 0.20%. The manufacturing process of the steel plate comprises the steps of KR, BOF smelting, LF, RH, slab continuous casting, slab slow cooling, heating, rolling, steel plate pile slow cooling and heat treatment, the matrix structure of the obtained steel plate is a uniform and fine ferrite and tempered pearlite mixed structure, and the grain size ranges from 8 micrometers to 15 micrometers. The yield strength of the transverse tensile property at the 1 / 4 position of the steel plate ranges from 376 MPa to 392 MPa, the tensile strength ranges from 528 MPa to 553 MPa, the ductility is larger than or equal to 27.0%, the yield strength of the transverse tensile property at the 1 / 2 position ranges from 359 MPa to 375 MPa, the tensile strength ranges from 524 MPa to 537 MPa, the ductility is larger than or equal to 26.5%, and the steel plate is excellent in performance, excellent in whole plate uniformity, good in plate shape and easy to weld.

The invention belongs to the technical field of rolling, and particularly relates to an anti-decarburization and anti-brittle failure controlled cooling process for a high-silicon-chromium alloy tool steel wire rod. Aiming at the dilemma that the hot-rolled wire rod which contains more than 2.0% of Si, more than 1.1% of Cr, Mo, V and other alloy elements not only meets the decarburization requirement of a product, but also does not have brittle failure of the wire rod, the method comprises the following steps: firstly, determining the cover entering temperature of the hot-rolled wire rod, the cooling speed of the wire rod before the hot-rolled wire rod enters the cover and other key process parameters; and then the method is realized by adjusting the speed of a roller way, the number of opened heat preservation covers after spinning, a fan Jinling device, the air volume of a fan, the spinning temperature and the like, so that the hot rolling structure of the wire rod is a pearlite structure which is not easy to brittle, and meanwhile, the requirement that the decarburization of a product does not exceed 0.55 D (D is the diameter of the wire rod) is met.