58results about How to "Increased pearlite content" patented technology

The invention relates to a production method of spheroidal graphite cast iron for hydraulic parts and prepared spheroidal graphite cast iron. The production method comprises the following steps of a material proportioning procedure, a charging melting procedure and a nodulizing inoculation procedure. In the material proportioning process of the material proportioning procedure, the adopted raw materials by weight part comprise 25-35 parts of pig iron for steelmaking, 33-43 parts of steel scrap, 26.5-36.5 parts of scrap return, 0.3-0.5 part of red copper and 0.5-2.5 parts of carburizing agent.A completely new formula is adopted. As a defined amount of red copper is added in ferritic nodular iron, a matrix structure can be added with 20-40 percent of pearlite content, the hardness can be increased by 8-10 percent, the tensile strength can be increased by 9-11 percent, the yield strength can be increased by 8-10 percent, and the elongation can be reduced by 20-30 percent. The too-soft defect of the ferritic nodular iron in the machining process can be obviously overcome, and the machining performance is increased.

The invention particularly relates to a vanadium-titanium gray cast iron and a production technique thereof. The vanadium-titanium gray cast iron contains 3.2-3.6% of C, 1.6-1.9% of Si, 0.7-0.9% of Mn, 0-0.10% of P, 0.07-0.12% of S, 0.15-0.20% of V, 0.07-0.12% of Ti, 0.25-0.35% of Cr, and the balance of Fe and other minor elements and inevitable impurities. The vanadium-titanium gray cast iron has the advantages of high tensile strength, favorable heat resistance and favorable wear resistance; and the type-A graphite content in the metallurgical structure is higher than 85%, the graphite length is Grade 3-5, the pearlite content in the matrix structure is greater than or equal to 98%, and the total content of carbides and iron phosphide eutectic is less than or equal to 2%.Late inoculation treatment is adopted to enhance the inoculation effect, improve the graphite form, eliminate the carbides and ferrite and increase the pearlite content. By using cheap vanadium-titanium pig iron as the raw material and avoiding adding noble alloys, the vanadium-titanium gray cast iron has the advantages of low cost and high performance.

The invention discloses as-cast high pearlite quantity and high vermicular rate vermicular graphite cast iron and a preparation method thereof. The vermicular graphite cast iron is prepared from the following components by weight percent: 3.5-3.8% of C, 2.2-2.4% of Si, 0.8-1% of Mn, 0.2-0.4% of Cu, 0-0.4% of Mo, 0.08-0.1% of Sn, 0.2-0.4% of Cr, 0.2-0.5% of Ni, 0.05-0.1% of Nb, less than or equal to 0.06% of S, less than or equal to 0 .06% of P, and the balance of Fe and impurities introduced by raw materials. The vermicular graphite cast iron with a high creep rate (90-98%) is obtained by using an Mg-RE creeping method for controlling; furthermore, by means of micro-regulation of multiple alloy elements, the vermicular graphite cast iron with a high high pearlite quantity (90%-100%) can bestably obtained; the tensile strength of the vermicular graphite cast iron is greater than or equal to 500MPa, the elongation of the vermicular graphite cast iron is greater than or equal to 1.5%, Brinell hardness of the vermicular graphite cast iron is 230-260HBW, and the microhardness of pearlite is 300-320HV. The vermicular graphite cast iron provided by the invention has the characteristics of being good in mechanical properties, thermal fatigue resistance, thermal crack resistance and wear resistance under the extremely harsh working conditions; the preparation method is simple in control method and can stably produce castings with excellent comprehensive performance, thus being suitable for industrial mass production.

The invention discloses a high-intensity gray pig iron inoculator and a preparation method thereof and belongs to the technical field of casting. The high-intensity gray pig iron inoculator comprises the following chemical components in percentage by weight: 65 to 72 percent of Si, 0.5 to 1.2 percent of Al, 0.5 to 1.5 percent of Zr, 0.6 to 1.8 percent of RE, 4.0 to 6.0 percent of Mn, 0.4 to 1.2 percent of Sn (or 0.1 to 0.4 percent of Sb), less than 0.2 of C, less than 0.02 of S, less than 0.05 of P, and the balance of iron and unavoidable impurities. The inoculator can obviously reduce chilling tendency, refine graphite and reduce wall thickness and sensitivity of tissues and obviously increase pearlite content, so that tensile strength of gray pig iron is improved. For base iron with the same components, compared with a common 75 silicon iron inoculator, the high-intensity gray pig iron inoculator has the advantage that the tensile strength of cast iron applying the high-intensity gray pig iron inoculator can be improved by 30 to 60MPa.

The invention discloses a production method of a cast-state ductile iron QT800-5 by using fired mold precision casting. The method comprises the following steps of fired mold precision casting of shell and shell making, molten iron smelting, spheroidizing treatment, inoculation treatment, mold shell casting and module cooling so as to obtain the QT800-5, wherein the requirements that the tensile strength Rm is larger than or equal to 800 MPa and the elongation percentage after fracture A is larger than or equal to 5% can be met. The production method of cast-state ductile iron QT800-5 by usingthe fired mold precision casting has the beneficial effects that low-cost copper and manganese are added to improve a pearlite content in a cast-state ductile iron matrix, the structure is strengthened and refined, the mechanical property of a material is improved, the cost can be effectively reduced, and the cast-state heat-free treatment is realized; and meanwhile, deformation is avoided afterthe heat treatment of a casting is avoided.

The invention discloses a vanadium-chromium microalloying large-specification 500MPa ultra-fine grain corrosion-resisting anti-seismic steel bar and a preparation method thereof. The steel bar comprises, by weight percent, 0.21-0.25wt% of C, 0.45-0.55wt% of Si, 1.25-1.40wt% of Mn, 0.30-0.35wt% of Cr, 0.065-0.080wt% of V, not larger than 0.040wt% of S, not larger than 0.045wt% of P, not larger than0.0070wt% of O, 0.0165-0.0200wt% of N and the balance Fe and inevitable impurities. The preparation method of the steel bar comprises the procedures of molten steel smelting, deoxidization alloying,LF furnace refining, casting, steel blank heating and controlled rolling and controlled cooling. A certain amount of vanadium-containing pig iron is added into a tapping steel ladle to replace the expensive vanadium alloy, the V content of molten steel is increased, and the adding quantity of the vanadium alloy is reduced; in the deoxidization alloying process, a small quantity of silicon-nitrogenalloy is added, the nitrogen content in the molten steel is increased, and the proportion value of V / N in the steel is reduced, transferring of V from the solid solution state to a carbonitride precipitated phase in the rolling process is promoted, and the precipitation strength effect of the steel is obviously improved; and the preparation method is low in production cost and high in process applicability and controllability.

The invention discloses a hydraulic part servo valve body material formula and a preparation process thereof. The method comprises the following steps of: (1) smelting by adopting an electric furnace, adding 15-25 parts (in parts by weight) of raw iron, 40-60 parts of waste steel and 20-40 parts of foundry returns into the electric furnace for melting; (2) adding Sn in the electric furnace after melting; (3) continuously adding ferrochrome into the electric furnace; (4) then, continuously adding copper; (5) then carrying out inoculation treatment in three steps; (6) pouring liquid-state cast iron into a casting mould cavity of a sand mould to form hydraulic part servo valve body blank. According to the invention, formation of thick sheet-shaped graphite can be prevented, hard spot shaped small holes can be prevented, and mechanical performances of cast iron can be improved.

The invention discloses a nitrogen-rich microalloy fine grain HRB400E straight aseismic steel bar and a preparation method thereof. The steel bar is prepared from the following chemical components in parts by weight: 0.21 to 0.25 weight percent of C, 0.42 to 0.55 weight percent of Si, 1.38 to 1.50 weight percent of Mn, 0.012 to 0.020 weight percent of V, less than or equal to 0.045 weight percent of S, less than or equal to 0.045 weight percent of P, 0.0090 to 0.0115 weight percent of N and the balance of Fe and inevitable impurities. The steel bar is prepared through the following steps of molten steel smelting, deoxidation alloying, molten steel argon station refining, molten steel casting, steel billet heating and steel billet controlled rolling and controlled cooling in sequence. The process disclosed by the invention has the characteristics of low production cost, high process applicability, high controllability and the like, and various strengthening effects such as precipitation strengthening, fine grain strengthening and the like are fully exerted by integrating and innovating chemical component design, converter smelting, a deoxidation alloying structure, continuous casting, a steel rolling heating schedule, rolling temperature and a controlled cooling process; and the produced reinforcing steel bar has the advantages of excellent and stable process mechanical properties, fine and uniform microscopic structure, good plasticity and toughness, excellent anti-seismic property and the like.

The invention relates to a special cleansing agent for short-flow high-strength cast iron and a manufacturing process thereof, belonging to the technical field of cast iron production flow. The cleansing agent consists of the following components in parts by weight: 6-18 parts of rare earth oxide, 29-49 parts of calcium oxide, 19-29 parts of aluminum oxide and 4-8 parts of carbon. The cleansing agent is manufactured by the following steps of: based on rare-earth selected mineral powder, high-purity calcium oxide powder, bauxite powder and coke powder as raw materials, adding a fluxing agent, roasting a mixture of the raw materials and the fluxing agent at high temperature, and electrically melting and spraying the mixture to obtain the special cleansing agent. The special cleansing agent disclosed by the invention can change conditions of thermodynamics and dynamics of a metallurgical reaction of blast-furnace molten iron, and eliminates or restrains a hereditary defect of vicious expansion of thick graphite of the blast-furnace molten iron so as to form a comprehensive strengthening effect with an inoculant; and high-strength cast iron mainly comprising A-type graphite and havingmore than 95% of pearlite and 250-350MPa of tensile strength can be obtained.

The invention discloses a ductile iron casting and the casting process thereof. The ductile iron casting comprises the following components according to weight percent: 3.5 to 3.7 percent of carbon, 2.0 to 2.4 percent of silicone, 0.4 to 0.8 percent of manganese, 0.04 or less than 0.4 percent of sulfur, 0.06 or less than 0.06 percent of phosphorus and 0.15 to 0.25 percent of chromium, and the rest is Fe. The preparing process of the ductile iron casting comprises the steps of smelting, balling, breeding, molding and detecting. According to the invention, chemical composition of casting is improved, the chromium is used for replacing precious metal copper and tin, the content of pearlite is also increased, the wearing resistance of the casting is improved, heat treatment is not required, that the requirements of a special petroleum pump for petroleum enterprises are met is detected, due to the improvement to matching components, the smelting and casting process of the invention is enabled to be more reasonable, the smelting cost is lower, the self feeding capacity of the casting is excellent, and dense tissue can be obtained easily after cooling.

The invention belongs to the technical field of casting processes for pressure discs, and particularly relates to a casting process for a clutch pressure disc. The casting process comprises the steps of molten iron preparation, molten iron standing and casting forming. Compared with the prior art, the casting process has the advantages that: pearlite content of a cast piece is increased, so that the metallographic structure and mechanical properties of the cast piece can meet requirements so as to perform nondestructive examination on the cast piece; examination requirements of radiographic inspection I-grade, ultrasonic flaw detection I-grade and magnetic powder inspection I-grade are met; the clutch pressure disc is manufactured through a casting method and a casting device; and a metal usage rate is increased by 40% or more, and working efficiency is improved by about 60%.

The invention relates to the technical field of ferrous metallurgy, in particular to an anti-seismic reinforcing steel bar and a preparation method thereof.The anti-seismic reinforcing steel bar comprises, by weight, 0.20%-0.25% of C, 0.65%-0.80% of Si, 1.35%-1.60% of Mn, 0.090%-0.110% of V, 0.20%-0.30% of Cr, larger than or equal to 0.0180% of N, smaller than or equal to 0.035% of P, smaller than or equal to 0.035% of S, smaller than or equal to 0.55% of Ceq and the balance Fe and inevitable impurities. The beneficial influence of the specification effect of the small-specification HRB600E anti-seismic steel bar on the strength performance is fully considered, the C content is properly reduced and controlled to be 0.20%-0.25%, Ceq is smaller than or equal to 0.55%, the requirements for the C content and the carbon equivalent of the 500 MPa-grade steel bar in the GB / T 1499.2-2018 standard are met, the continuous casting rejudgment of the 500 MPa-grade steel bar can be achieved on a production organization, the production efficiency is not affected, the production organization is facilitated, and waste judgment loss is reduced.

The invention relates to the field of manufacturing structural steel for highway guardrails, in particular to a low-alloy, high-strength, high-weathering structural steel for highway guardrails and a preparation method thereof. In terms of mass percentage, the chemical composition of structural steel is: C≤0.12%; Si≤0.65%; Mn≤1.20%; P: 0.07~0.12%; S≤0.030%; Cu: 0.20~0.55%; Cr: 0.30~1.25 %; Ni: 0.12~0.65%; Nb≤0.03%; Al≤0.05%, Fe is the balance. On the basis of the existing low-alloy high-strength weather-resistant steel, the present invention improves the compactness of the rust layer by optimizing the P element, thereby improving the weather-resistant performance of the structural steel; increasing the Cr content, increasing the compactness of the rust layer and the pearlite content, and improving the structure The weather resistance and mechanical properties of steel; increase the Nb element, refine the grain size of steel, and improve the comprehensive mechanical properties of materials. The invention can meet the requirements of the road guardrail on weather resistance and strength performance.