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2732 results about "Ductile iron" patented technology

Ductile iron, also known as ductile cast iron, nodular cast iron, spheroidal graphite iron, spheroidal graphite cast iron and SG iron, is a type of graphite-rich cast iron discovered in 1943 by Keith Millis. While most varieties of cast iron are weak in tension and brittle, ductile iron has much more impact and fatigue resistance, due to its nodular graphite inclusions.

Centrifugal casting high-speed steel composite roll and manufacture method thereof

The invention relates to a centrifugal casting high-speed steel composite roll and a manufacture method thereof and belongs to the field of casting. The composite roll is composed of outer layer high-speed steel, middle layer graphitic steel and core high-strength nodular cast iron by centrifugal compounding. The centrifugal casting high-speed steel composite roll is based on the conventional high-carbon high-vanadium high-speed steel roll, the content of vanadium is appropriately reduced, niobium is added at the same time, and the Nb / V is controlled to be 0.3 to 0.5 so that Nb and V form complex carbide (V, Nb) C so as to avoid forming segregation under the action of centrifugal force. A roll core of the high-speed steel composite roll adopts high-strength nodular cast iron, and a multivariate graphite steel middle layer is poured between an outer layer and the roll core for preventing interfusing elements of Cr, B, and the like which cause embrittlement when the nodular cast iron is poured to be fused with the outer layer high-speed steel. Microalloying processing for refining the organization is carried out on a roll surface high-speed steel material and the middle layer graphitic steel so as to achieve the purpose of improving the thermal cracking capacity of the roll material. The centrifugal casting high-speed steel composite roll has high overall performance, long service life and good economic benefits.
Owner:BEIJING UNIV OF TECH

Method for producing low-temperature impact resistance high-strength nodular cast iron

The invention discloses a method for producing low-temperature impact resistance high-strength nodular cast iron, which comprises processes of material preparing, smelting, desulfurizing, molten iron adjusting and spheroidizing. The method is characterized in that: in the material preparing process, based on 100 percent, base iron accounts for 30 to 70 percent, steel scarp accounts for 10 to 20 percent, and recirculated iron accounts for 10 to 60 percent; other additives are added based on the total weight of the base iron, the steel scarp and the recirculated iron, wherein spheroidizing agent accounts for 1.6 to 2.0 percent, inoculant accounts for 0.4 to 0.6 percent, desulfurizer accounts for 1.2 to 1.8 percent, and carburant accounts for 1 to 3 percent; furthermore, 0.15 to 0.50 percent of Cu is added. On the premise of ensuring low temperature impact performance, the nodular cast iron improves strength,, meets the requirement that the nodular cast iron of the mark has higher low-temperature impact resistance and high normal-temperature strength, and can be widely used for manufacturing important high-strength cast of vehicles, locomotive, draught fans and engineering machinery used in low temperature environment and manufacture of cast having strict requirement on fatigue strength.
Owner:山东汇金股份有限公司

High-speed steel composite roller and casting method thereof

The invention belongs to the field of steel rolling manufacture, specifically is a high-speed steel composite roll for strip mill in steel rolling industry and casting method thereof. The outer layer of the composite roll is made of high-speed steel, the middle layer is made of ductile cast iron base iron or graphite semisteel, the core is made of ductile cast iron. The invention employs centrifugal compound foundry technique, the roll is moulded by three times of casting. Constant centrifugal rotating speed is kept in centrifuge, the metal material of the outer layer and the middle layer are mould cast, and then the metal of the roll core is statically cast to form the final product. Compared with former dual-layer or other three-layer composite high-speed steel rolling rolls, the three layers of metal of the high-speed steel composite roll of the invention are well combined and have high strength; the optimal selection of the material of the middle layer improves the strength of the bonding layer, the carbide affecting the binding performance in the middle layer is reduced, the spreading of alloy element in the outer layer high-speed steel to the core, which affects the core material performance, is also effectively avoided by the middle layer, cracking and dropping off of the working layer in hot processing and rolling process are prevented as well.
Owner:INST OF METAL RESEARCH - CHINESE ACAD OF SCI

Smelting method for medium-thin wall cast-state nickel-free low-temperature ductile cast iron

The invention relates to a smelting method for medium-thin wall cast-state nickel-free low-temperature ductile cast iron. The medium-thin wall cast-state nickel-free low-temperature ductile cast iron comprises the following chemical components in percentage by mass: 3.5-4.1 percent of C, 1.7-2.2 percent of Si, 0.10-0.25 percent of Mn, not more than 0.035 percent of P, not more than 0.020 percent of S, 0.015-0.030 percent of Re, 0.025-0.045 percent of Mg, 0-0.20percent of Cu, less than 0.1 percent of residual element, and Fe in balancing amount. The medium-thin wall cast-state nickel-free low-temperature ductile cast iron is obtained by mixing furnace materials and carrying out high-temperature smelting in an intermediate-frequency furnace, modularization and inoculation treatment and casting and heat-insulating treatment on the mixed furnace materials. Cast iron products obtained by adopting the smelting method disclosed by the invention obtain normal-temperature mechanical property and low-temperature mechanical property under the cast state conditions; complex medium-thin wall parts are required to be subjected to low-temperature stress relief annealing; and simple medium-thin wall parts are free from being annealed, so that the production cost is greatly reduced, the production period is greatly shortened and the production efficiency is increased.
Owner:CRRC QISHUYAN INSTITUTE CO LTD

High-strength low-temperature-resisting spheroidal graphite cast iron and preparing method thereof

The invention relates to the field of spheroidal graphite cast iron, in particular to high-strength low-temperature-resisting spheroidal graphite cast iron and a preparing method thereof. The spheroidal graphite cast iron comprises, by mass percent, 3.2% to 3.5% of carbon, 2.1% to 2.3% of silicon, 0.4% to 0.5% of manganese, 0.4% to 0.6% of copper, 0.2% to 0.4% of nickel, 0.2% to 0.4% of molybdenum, 0.04% to 0.06% of magnesium, 0.05% to 0.08% of chromium, 0.005% to 0.008% of titanium, 0.002% to 0.003% of vanadium, not larger than 0.04% of phosphorus, not larger than 0.02% of sulphur and the balance iron. The preparing method of the high-strength low-temperature-resisting spheroidal graphite cast iron comprises following steps: firstly, raw materials are smelted; secondly, spheroidizing treatment and inoculation are carried out; and thirdly, heat treatment is carried out. Through reasonable arrangement of all element components, the tensile strength of the spheroidal graphite cast iron is improved, a proper nucleating agent is prepared, internal inoculation matched with inoculation in a ladle is adopted, the inoculation effect is reinforced, meanwhile, during heat treatment, the heating temperature, the heat preservation time, the cooling rate and the manner are reasonably arranged, the strength and low temperature resistance of the iron are effectively improved, the spheroidal graphite cast iron is high in strength and excellent in low temperature resistance, and the preparing method is simple and efficient.
Owner:HANSHAN COUNTY XINGDA DUCTILE IRON FACTORY

Melting process for producing synthetic cast iron by utilizing SiC carburizing siliconizing

The invention discloses a melting process for producing synthetic cast iron by utilizing SiC carburizing siliconizing, which produces the synthetic cast iron by taking scrap steel, pig iron and cast iron returns or scrap steel and cast iron returns as the main raw materials in an induction furnace by utilizing SiC as an carburizing siliconizing agent, wherein the addition of SiC is 0.5-3%, and thegranularity is 6-20mm; SiC is added to a hearth before melting or is added during the melting process, or the two modes cooperate to be used. The invention utilizes SiC to replace the pig iron and silicon iron carburizing siliconizing to reduce the pig iron and silicon iron so as to reduce the cost, and meanwhile, the tendency of the molten iron chill and the reverse chill of the produced synthetic cast iron is small; the dimensions of graphite pebbles in produced nodular cast iron are small, the sphericity or roundness is high, the content of ferrite is high, and the roughness of the nodularcast iron is improved; the organization of produced grey cast iron is refined, and the mechanical property and the abrasion resistance are obviously improved. The invention can be used for producingvarious trademarks of grey cast iron, nodular cast iron and alloy cast iron.
Owner:河南省金太阳精密铸业股份有限公司

Smelting technique for cast of wind energy apparatus

InactiveCN101407884AHigh nodularityMeet mechanical performance requirementsSmelting processLiquid iron
The invention discloses a smelting process of castings of wind energy equipment, which is suitable for the smelting production of castings of wind energy equipment with the wall thickness of 60 to 200mm and includes the following steps: a. new pig iron, scrap steel and carburants with special requirements are sent into a melting electric furnace for smelting; b. high temperature liquid iron is subjected to desulfurization treatment by a desulfurization agent; c. the desulfurized liquid iron is returned into a heat insulation electric furnace for component adjustment, and the carburant is added for carrying out pre-treatment of crystal nucleus to graphite in the liquid iron; d. spheroidization treatment is carried out to the liquid iron; e. an inoculant is added into the liquid iron for inoculation; f. the liquid iron is poured to casting sand mold; and g. the castings are naturally cooled to 500 to 550 DEG C for unpacking after finishing pouring. The smelting process of castings of wind energy equipment can increase the spheroidization efficiency of ductile iron castings used by the wind energy equipment, which causes the castings to have good intensity of tension, extensibility and high impact ductility in low temperature environments, thus meeting the requirements on the castings used by the wind energy equipment.
Owner:CHANGZHOU ZHUORUN WIND POWER EQUIP

Process for casting thick and large nodular cast iron valve plate

The invention provides a process for casting a thick and large nodular cast iron valve plate. The process comprises the following steps of: (1) manufacturing a mould; (2) manufacturing a casting mould and a sand core; (3) drying and integrating; (4) smelting; (5) pouring; and (6) shaking out and cleaning. In the process, a large number of external chilling blocks and sand separation chilling blocks are used on upper and lower surfaces of a casting for chilling, appropriate placing positions and thickness are selected, and shrinkage cavity and shrinkage porosity of the casting are effectively avoided; meanwhile, a good graphite balling state is ensured by quickly chilling, a feeding head is avoided, the casting is easy to clean, 5 percent of molten iron using amount is saved, and production cost is reduced; a semi-closed casting system is adopted by a casting system, an ingate is uniformly distributed around the casting mould, and the casting mould is slightly scoured, and a good residue stopping effect is achieved; and under the action of chilling of chilling blocks, the thick and large nodular cast iron casting which is smelted by a cupola furnace is good in moulded surface, and meets production requirements, offscourings and sand are avoided, and process yield is improved by 5.9 percent.
Owner:TIJIN YIJI MACHINERY

High-strength low stress cast nodular cast iron with high elasticity modulus and manufacturing method thereof

The invention discloses a high-strength low stress cast nodular cast iron with high elasticity modulus. The nodular cast iron comprises the following components by mass percent: 3.7-3.9% of C, 2.0-2.2% of Si, 4.50-4.65% of CE, 0.5-0.6% of Mn, less than or equal to 0.03% of P, less than or equal to 0.02% of S, 0.03-0.06% of Mg, 0.01-0.02% of RE, 0.5-0.7% of Cu, and 0.05-0.06% of Sn. A manufacture method of the nodular cast iron is characterized by high temperature pure iron liquid of base iron, compound alloying and accurate addition; according to the microscopic structure of the manufactured nodular cast iron, the content of pearlite is more than or equal to 95%, the nodularity is more than or equal to 90%, spherulitic graphite number in unit area is 200-380 / mm<2>, the yield strength is over 400MPa, the strength of extension is over 700MPa, the elastic modulus is more than 170GPa, the hardness HB is 190-250, the elongation is more than 3%, the casting inner stress is less than or equal to 50MPa, namely, with high carbon equivalent and high silicon-carbon ratio, the nodular cast iron has excellent performances such as high strength, high elasticity modulus and low stress, thus meeting the technical requirement of casting of machine tools.
Owner:ZHENGZHOU RES INST OF MECHANICAL ENG CO LTD

Carbide-containing austempered ductile iron plowshare and production method thereof

The invention discloses a carbide-containing austempered ductile iron plowshare, which uses austempered ductile iron as a raw material, wherein the ductile iron comprises the following chemical components in percentage by weight: 3.40 to 3.80 percent of C, 2.20 to 2.80 percent of Si, 0.20 to 0.50 percent of Mn, less than or equal to 0.03 percent of P, less than or equal to 0.02 percent of S, 0.03 to 0.04 percent of Mg, 0.01 to 0.02 percent of Re, 0.25 to 0.5 percent of Cr, and the balance of Fe; the graphite metallurgical structure in the ductile iron is characterized by a spheroidization rate of above grade-2, a graphite size of above grade-6 and a graphite quantity of more than 100 per square millimeters. The matrix of the ductile iron is martensite and lower bainite and residual austenite and carbide, wherein the carbide is less than 2 weight percent. The carbide-containing austempered ductile iron plowshare has the advantages of improving the conventional process for finely casting plowshares by using low alloy steel in the past, having a service life which is more than three times as long as that of the low alloy steel plowshares and a price as low as two thirds of that of the low alloy steel plowshares and greatly reducing agricultural production cost.
Owner:宣化冶金工业有限责任公司
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