31results about How to "Improve nodularity" patented technology

The invention discloses high-strength nodular cast iron QT900-6 which consists of the following elements in percentage by weight: 3.2-3.7% of C, 2.4-2.8% of Si, less than or equal to 0.2% of Mn, less than or equal to 0.03% of P, 0.005-0.02% of S, 0.8-1.4% of Cu and the balance of Fe and unavoidable trace elements. The high-strength nodular cast iron QT900-6 has high compressive strength, high yield strength and excellent mechanical property.

The invention discloses a working roll for rolling a medium-thickness plate with high grade and high strength and a manufacture method thereof. The working roll is applied to a medium-thickness plate rolling mill of a rolling steel industry. A working layer comprises the following alloy components in percentage by weight: 3.00-3.50 percent of C, 0.40-1.20 percent of Si, 0.50-1.20 percent of Mn, not more than 0.10 percent of P, not more than 0.05 percent of S, 1.30-2.50 percent of Cr, 3.20-4.50 percent of Ni, 0.20-1.00 percent of Mo, 0.20-2.00 percent of W and 1.00-1.50 percent of V. A roll core comprises the following chemical components in percentage by weight: 2.80-3.50 percent of C, 2.00-2.50 percent of Si, 0.50-1.00 percent of Mn, not more than 0.10 percent of P, not more than 0.05 percent of S, 0.20-0.50 percent of Cr, 0.20-0.60 percent of Ni, not more than 0.20 percent of Mo and not more than 0.30 percent of Re. The working roll manufactured by adopting a centrifugal composite casting process and two-section tempering production at 400-550 DEG C for 25-30 hours is the working roll for rolling the medium-thickness plate with high grade and high strength, which has the advantages of high abrasion resistance and less hardness reduction.

The invention discloses a medium silicon molybdenum niobium spheroidal graphite cast iron material and a preparation method thereof. The medium silicon molybdenum niobium spheroidal graphite cast iron material is prepared from the following chemical components in percentage by mass: 2.8-3.2% of C, 4.2-4.5% of Si, less than or equal to 0.4% of Mn, less than or equal to 0.04% of P, less than or equal to 0.015% of S, 0.8-0.9% of Mo, 0.6-0.9% of Ni, 0.4-0.7% of Nb, 0.03-0.06% of Mg, 0.15-0.25% of V and the balance of Fe and inevitable other elements. Since C04 high-purity pig iron and waste steel are taken as raw materials, a medium-frequency induction furnace is adopted for smelting, and a carburant, silicon carbide, ferrocolumbium, nickel plates, ferrosilicon and ferrovanadium are added in different time phases of smelting, raw iron chemical components and smelting temperature expected by design can be achieved, and the product disclosed by the invention can be prepared through nodulization and two times of inoculation. By adopting the edium silicon molybdenum niobium spheroidal graphite cast iron material disclosed by the invention, an exhaust manifold of an engine can work under a working condition of about 800 DEG C, the high-temperature use property of the exhaust manifold can be improved, and the service life of the exhaust manifold can be prolonged.

The invention relates to the field of as-cast high-strength high-elongation synthetic nodular cast iron. The invention relates to as-cast high-strength high-elongation synthetic nodular cast iron anda preparation method thereof. The nodular cast iron is characterized in that under the as-cast condition, the nodular cast iron meets performance requirements that the tensile strength Rm is larger than or equal to 700 MPa, and the percentage elongation A after fracture is larger than or equal to 10%; the matrix is a pearlite-ferrite mixed matrix; the content of pearlite is 55%-75%, a spheroidizing grade is 1-2, a graphite size grade is 6-7, the nodular cast iron is composed of elements, by mass, 3.5%-3.7% of C, 2.9-3.3% of Si, less than or equal to 0.2% of Mn, less than or equal to 0.035% ofP, less than or equal to 0.02% of S, 0.5%-0.7% of Cu, 0.55%-0.75% of Ni, 0.030%-0.065% of Mg and the balance of Fe and trace elements. The method has the beneficial effects that scrap steel and raw material pure iron are adopted for recarburization, base iron is smelted in a medium-frequency induction furnace, then pretreatment, spheroidizing treatment and inoculation treatment are conducted, final pouring is conducted, and QT700-10 is achieved under the as-cast condition.

The invention discloses a casting method of a high-powered engine box casting. The casting method comprises the steps of preparing moulding sand, performing modeling and core making to obtain a sand mould, preparing pouring iron liquid, taking pig iron, foundry returns and waste steel as raw materials to be fed into a smelting furnace to be smelted, carrying out in-package inoculation and spheroidization on the smelted iron liquid, carrying out stream inoculation before tapping, then carrying out tapping, pouring the iron liquid into the sand mould, carrying out stream inoculation, adopting acold iron riser process for feeding and temperature control, forming a casting after pouring is finished, and carrying out treatment on the formed casting. The obtained casting is good in quality, andquality problems of core clamping, shrinkage, cracks and the like are not prone to happening.

The invention discloses a pure magnesium spheroidizing technology of lost foam ductile cast iron. The pure magnesium spheroidizing technology comprises the steps that a spheroidizing agent is placed into a lip-pour ladle reaction chamber, a cover of the reaction chamber is closed, and a conventional nucleating agent, ferrosilicon, is added into a lip-pour ladle; after molten iron in a heat-insulated furnace is subjected to deslagging, molten iron is added into the lip-pour ladle, and the temperature of molten iron is controlled to be 1520 DEG C to 1560 DEG C; then, the lip-pour ladle is overturned, and molten iron and the spheroidizing agent react for 60 s to 70 s; and pouring is carried out while stream inoculation is achieved, wherein the addition amount of the stream nucleating agent is 0.08% to 0.15% of the weight of molten iron; the spheroidizing agent is a mixture of pure magnesium ingots and calcium chloride; and the weight ratio of molten iron to the pure magnesium ingots to calcium chloride to ferrosilicon is 1000 to (1.4 to 2.0) to (0.2 to 0.5) to (4 to 8). According to the pure magnesium spheroidizing technology of lost foam ductile cast iron, the spheroidizing problem of high-sulfur high-silicon molten iron can be effectively solved, the spheroidizing grade is high, a required matrix structure can be obtained, the problems that the spheroidizing effect is poor, the quality of castings is not stable, and the rejection rate is high are solved, the technology does not require lip-pour ladle nucleating, the procedures can be decreased, and the labor intensity is reduced.

The invention provides a kind of as-cast high-strength and ductility synthetic nodular cast iron QT800-5 and a preparation method thereof. The as-cast high-strength and ductility synthetic nodular cast iron QT800-5 comprises, by mass, 3.70-3.95% of C, 3.3-3.5% of Si, less than or equal to 0.2% of Mn, less than or equal to 0.035% of P, less than or equal to 0.02% of S, 0.5-0.7% of Cu, 0.55-0.75% ofNi, 0.035-0.65% of Mg residues, and the balance Fe and microelements. The preparation method of the as-cast high-strength and ductility synthetic nodular cast iron QT800-5 comprises the following steps of mixing and smelting; alloying; pretreatment and spheroidizing; and inoculation treatment and pouring. The preparation method comprises the steps of smelting base iron melt in a medium-frequencyinduction furnace through steel scrap recarburization; adding silicon iron and cathode copper to conduct alloying; bringing in alloying elements nickel through a spheroidizing agent; conducting pretreatment, spheroidizing and inoculation treatment; and finally conducting pouring. The as-cast high-strength and ductility synthetic nodular cast iron QT800-5 prepared through the method has high strength, good ductility and toughness and excellent comprehensive performance.

The invention relates to a microalloying element and an instantaneous metal-stream inoculant for controlling the microporosity of a large-section ductile iron casting. The microalloying element and the instantaneous metal-stream inoculant are characterized in that the microalloying element is a combination of Cu and Sn, and SiRE is adopted as the instantaneous metal-stream inoculant and comprises, by weight percentage, 65-80% of Si, 1.0-2.5% of RE, 0.65-1.35% of Ca, 4-6% of Al and the balance Fe. A method for controlling the microporosity of the large-section ductile iron casting has the beneficial effects that through the synergistic effect of the microalloying element and the instantaneous metal-stream inoculant, the spheroidization grade of molten iron is increased, the number of graphite in the later period of the solidification of the molten iron is increased, the graphite is refined, and the rejection rate generated due to the fact the quality and performance of the large-section ductile iron casting do not meet the requirements due to the microporosity is reduced.

The invention discloses an integrated convenient-to-hang environment-friendly high-performance liquid alloy half-pressure container and a using method. The container comprises a container body capable of turning over, a receiving trough matched with the container body is arranged at the upper end of the container body, a cantilever is connected to the top end of the receiving trough and mounted on a frame which is connected with two side faces of the container body, an iron filling hole communicated with the inside of the container body is formed in the receiving trough, and a slag avoiding mouth communicated with the inside of the container body is connected to the side face of the container body. The container and the using method have the advantages that environmental protection and greenness are realized, and local environmental pollution is reduced by more than 90%; magnesium absorption rate and nodulizing grade are high; consumption of nodulizing agents is less, and heat insulation effect is good; nodulizing effect is stable; iron liquid is basically lossless; physical properties of castings are improved; a container cover is omitted, so that labor intensity of workers is reduced.

The invention relates to a low-cost seawater-corrosion-resistant nodular cast iron and a preparation method thereof, and belongs to the technical field of casting alloys. The nodular cast iron comprises the following chemical components: 3.5-3.9% of C, 2.3-2.9% of Si, 0.5-2.0% of Zn, less than 0.3% of Mn, less than 0.025% of S, less than 0.06% of P, 0.03-0.05% of Mg residues, 0.02-0.04%of Re residues and the balance of Fe. Low-price industrial waste steel is adopted as the main raw material for producing the nodular cast iron, zinc-containing core-spun yarn is added before discharging, precious metal such as nickel in the corrosion-resistant nodular cast iron is replaced with zinc, the production cost is low, and energy conservation and environmental protection are achieved. The preparation method comprises the following steps: (1) adding raw materials into a medium-frequency electric furnace to be smelted into molten iron, adding the zinc-containing core-spun yarn before discharging, and then performing discharging; (2) carrying out purification treatment during spheroidizing and inoculation treatment of molten iron; and (3) performing pouring to obtain the nodular cast iron. The spheroidization level of the prepared nodular cast iron is 1-2 level, the spheroidization rate is larger than or equal to 90%, the ferrite content is larger than or equal to 90%, the tensile strength is larger than or equal to 450 MPa, the elongation is larger than or equal to 10%, and the nodular cast iron can normally work in the marine environment and has remarkable beneficial effects.

The invention discloses an S195 ductile iron camshaft metal mold casting technology. The inclination of a metal mold cavity is between 40 degrees and 60 degrees; and a metal mold is made of HT20-40. The S195 ductile iron camshaft metal mold casting technology comprises the following steps: coating a paint by adopting a spray finishing method, heating a metal mold to a proper temperature before spraying and spraying, warming and preheating the metal mold by taking a drying mold with the coating thickness of about 0.4-0.6mm, pouring preferably at the preheated temperature of 200-250DEG C (heating pouring temperature to 1320-1380DEG C by adopting a drying oven; pouring time: 6-8s) and then performing air cooling, cooling a casting at 800-850DEG C and performing casting discharge and immediately embedding into dry sand. The S195 ductile iron camshaft metallic casting technology has the advantages that the spheroidization rate is improved, textures are fined, and comprehensive mechanical property can be improved; in addition, due to the coagulating property of ductile iron, not only can the microporosity of the casting be reduced by the metal mold, but also the casting is accurate in dimensions, energy can be saved, and no environment pollution exists.

The invention belongs to the technical field of casting and relates to a pipe nodular cast iron manufacturing method. The method comprises iron liquid melting preparation, nodulizing and inoculation treatment. The pipe nodular cast iron greatly improves high temperature creep resistance and creep fracture resistance of a casting, has cyclic failure frequency of 410-440 times at a thermal cyclic temperature of 500-600 DEG C, has high temperature tensile strength of 130-140N/mm<2> at a temperature of 600 DEG C, and has tensile strength of 620-650N/mm<2>, yield strength of 500-530N/mm<2>, elongation percentage of 4.5-5.5%, hardness of 245-255HB and a yield ratio of 0.8-0.9 at a room temperature. The pipe nodular cast iron has a high yield ratio and good heat resistance, reduces casting deformation probability, prolongs a service life and satisfies requirements on high temperature mechanical properties and antioxidation performances of nodular cast iron.

The invention discloses a preparation process of a high-quality diesel engine bearing cover. After spheroidizing and inoculating treatment are performed on base iron for a period of time, secondary silicon carbide and a secondary inoculant are added; the purity of the secondary silicon carbide is limited to be 95 percent or above; graphitization is promoted in the base iron through rare earth metal lanthanum and magnesium in a spheroidizing agent and a silicon-barium inoculant, and graphite nucleation is formed; silicon carbide with the purity being 95 percent or above is added; the dendritic crystals of austenite in the molten iron can be micronized; the micronized austenite dendritic crystals can increase graphite cores formed among the dendritic crystals; and the number of graphite nodules in the molten iron is increased, and the spheroidization rate is increased. The engine bearing cover prepared by the preparation process is processed by using a proper formula and adjusting the element proportion, and the bearing cover with good spheroidization rate and mechanical property is obtained by adopting a processing technology of secondarily adding silicon carbide and the inoculant, so that the engine bearing cover has good practicability and production value.