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950 results about "Pearlite" patented technology

Pearlite is a two-phased, lamellar (or layered) structure composed of alternating layers of ferrite (87.5 wt%) and cementite (12.5 wt%) that occurs in some steels and cast irons. During slow cooling of an iron-carbon alloy, pearlite forms by a eutectoid reaction as austenite cools below 727 °C (1,341 °F) (the eutectoid temperature). Pearlite is a microstructure occurring in many common grades of steels.

Steel plate for stamping and quenching and thermoforming method of steel plate

The invention discloses a steel plate for stamping and quenching and a thermoforming method of the steel plate. The steel plate comprises the following chemical components in percentage by weight: 0.14-0.28% of C, less than 0.40% of Si, 0.4-2.0% of Mn, less than or equal to 0.010% of P, less than or equal to 0.004% of S, 0.016-0.040% of Al, 0.15-0.8% of Cr, 0.015-0.12% of Ti, 0.0001-0.005% of B, less than or equal to 0.005% of N, and the balance of Fe and inevitable impurities. The thermoforming method comprises the following steps: blanking by shearing the steel plate, and heating at Ac3 to (Ac3+80) DEG C to carry out austenization; after insulating for 5-10 minutes in the heating furnace, immediately transferring the steel plate to a metal mold the inside of which is cooled by introducing water, and stamping at the high temperature of 650-850 DEG C; cooling the formed workpiece in the closed mold, and cooling the mold by water circulation in the mold, wherein the cooling rate is greater than the critical cooling rate when austenite forms martensite, and the temperature of the workpiece leaving the hot stamping production line is below 150 DEG C; and carrying out air-cooling to room temperature. The steel plate has the advantages of simple component system and favorable hardenability; and the substrate tissues, which are ferrite and pearlite, are processed by hot stamping andquenching to obtain the all martensitic structure. The tensile strength of the steel plate can be higher than 1300 N/mm<2>.
Owner:ANGANG STEEL CO LTD

Niobium alloy cast iron brake disk material and technique for producing the same

The invention relates to a material for a niobium alloy cast iron braking disc and a production technology thereof, and belongs to the field of production technology of high-carbon equivalent hypereutectic gray cast iron. The material for the niobium alloy cast iron braking disc comprises the following chemical compositions in weight percentage: 3.7 to 3.9 percent of carbon, 1.8 to 2.2 percent of silicon, 0.5 to 0.8 percent of manganese, less than or equal to 0.08 percent of sulfur, less than or equal to 0.60 percent of copper, less than or equal to 0.20 percent of nickel, less than or equal to 0.05 percent of vanadium, less than or equal to 0.05 percent of stannum, less than or equal to 0.05 percent of titanium, less than or equal to 0.25 percent of chrome molybdenum, 0.08 to 0.3 percent of niobium, and the balance being iron, wherein the iron is melted by an intermediate frequency furnace. The structure of the material is characterized by comprising pearlite, graphite (A3-5), and a small amount of ferrite The performance characteristics of the material are as follows: the hardness HB is more than or equal to 150 and the tensile strength is more than or equal to 170 N/mm<2>. The material is suitable for braking discs for medium-to-high grade sedans made of gray cast iron, and has the advantages of stable performance, low cost, longer service life, and convenient processing.
Owner:SHANGHAI UNIV +1

Tensile strength more than or equal to 780MPa grade hot-rolled dual phase steel and production method thereof

The invention provides tensile strength more than or equal to 780MPa grade hot-rolled dual phase steel. The dual-phase steel comprises the following components in percentage by weight: 0.05-0.08 percent of C, not more than 0.5 percent of S, 0.6-1.2 percent of Mn, less than or equal to 0.015 percent of P, less than or equal to 0.005 percent of S, less than or equal to 0.006 percent of N, 0.01-0.1 percent of Als, 0.05-0.25 percent of Ti, less than or equal to 0.6 percent of Cr or less than or equal to 0.003 percent of B or mixture of Cr and B. The production method by using CSP comprises the following steps: melting and continuously casting to form a slab; heating the continuous cast slab; rolling; carrying out laminar cooling; reeling; and naturally cooling to room temperature. The hot-rolled dual phase steel has the tensile strength of more than or equal to 780MPa, elongation of more than or equal to 15 percent and yield ratio of less than or equal to 0.70. An insulation cover additionally covers the intermediate insulation section, and the band steel cooling speed is reduced, so that generation of pearlite phase change can be effectively prevented. Production of hot-rolled dual phase steel with thickness of 1.2-4.0mm can be realized, the product has the advantages of uniform structure, small molding resilience and no cracking, existing equipment is utilized without adopting ultra fast cooling and other equipment, the production efficiency is high, and the investment is small.
Owner:武汉钢铁有限公司

Hot rolled steel sheet having superior hot press forming property and high tensile strength, formed article using the steel sheet and method for manufacturing the steel sheet and the formed article

There are provided a hot rolled steel sheet that has superior hot press forming property and high tensile strength and is used for structural members and their parts of automobiles and the like, a formed article, and a method for manufacturing the hot rolled steel sheet and the formed article. The hot rolled steel sheet having superior hot press forming property and high tensile strength includes, by weight: C: 0.1 to 0.5%, Mn: 1.0 to 3.0%, Si: 0.5% or less, W: 0.1% or less, N: 0.01 to 0.1%, Al: 0.01 to 0.1%, S: 0.03% or less, P: 0.1% or less and B: 0.001 to 0.01%, at least one element selected from the group consisting of Ti: 0.001 to 0.1%, Nb: 0.001 to 0.1% and V: 0.001 to 0.1%, at least one element selected from the group consisting of Mo: 0.01 to 1.5%, Cr: 0.01 to 1.5%, Cu: 0.005 to 1.0% and Ni: 0.005-2.0%, and the balance of iron (Fe) and other inevitable impurities, wherein a structure of the hot rolled steel sheet includes 10% or less of proeutectoid ferrite, 10% or less of pearlite and the balance of bainite, or includes 10% or less of proeutectoid ferrite, 10% or less of pearlite and the balance of bainite and martensite.
Owner:POHANG IRON & STEEL CO LTD

Production process of high-cleanliness non-quenched and tempered plastic mold thick steel plate

InactiveCN104451417AMinus does not generateImprove quality requirementsManganesePearlite
The invention relates to a production process of a high-cleanliness non-quenched and tempered plastic mold thick steel plate. The high-cleanliness non-quenched and tempered plastic mold thick steel plate is chemically composed of, by weight percentage, 0.25-0.45% of carbon, 0.20-0.50% of silicon, 0.70-1.50% of manganese, 0.70-2.00% of chromium, 0.15-0.55% of molybdenum, less than 0.01% of phosphorus, less than 0.005% of sulfur, 0.0010-0.030% of calcium, balanced iron and inevitable impurities. The chemical composition is simple in design; by means of the C-Mn-Cr-Mo alloying technology, the content of Mn and Cr can be improved;, by adding a certain amount of Mo, conversion of austenite to ferrite and pearlite can be inhibited, so that the high-cleanliness non-quenched and tempered plastic mold thick steel plate can have high hardenability and obtain a bainite structure; without the elements of Ti and V which are prone to generating inclusions, relatively clean steel can be obtained. The high-cleanliness non-quenched and tempered plastic mold thick steel plate has the advantages of being internally clean and compact, low in content of inclusions and capable of fundamentally eliminating pores, can meet the requirements of advanced plastic molds on internal high quality of steel and can be applied to the plastic mold industries such as automobile and electric appliances.
Owner:SGIS SONGSHAN CO LTD

Annealing-free medium-high carbon steel plate making technology

ActiveCN103173598AHigh elongation after breakReduce hardnessPearliteSteel plates
The invention relates to an annealing-free medium-high carbon steel plate making technology, and belongs to the technical field of steel rolling technologies. A technical scheme adopted in the invention is characterized in that the technology comprises the operations of heating furnace heating, vertical roll rolling, roughing scale removal, roughing rolling, intermediate cooling, precision rolling scale removal, precision rolling, laminar cooling, reeler reeling and concentrated pile cooling, the intermediate cooling operation is carried out after the roughing rolling operation and before the precision rolling scale removal operation and is realized through cooling plate blanks by a cooling device, and the cooling capability of the cooling device makes the temperature of the plate blanks decrease to below 840DEG C. The technology has the following beneficial effects: the elongation rate after fracture of produced products obviously rises, the hardness of the products decreases by 7.2-21%, the proportion of ferrite in the structure of the products is above 60%, ferrite crystal grains are appropriately coarsened, the pearlite colony is small and dispersed, and the cementite sheet in pearlite is attenuated, fragmented and partially granulated. An annealing operation after rolling can be avoided because of the low hardness and high plasticity in order to reach an online softening purpose.
Owner:HEBEI IRON AND STEEL

Bainite steel and methods of manufacture thereof

InactiveCN102112644AManganeseAlloy
Super Bainite Steel is described comprising between 90 % and 50 % bainite, the rest being austenite, in which excess carbon remains within the bainitic ferrite at a concentration beyond that consistent with equilibrium; there is also partial partitioning of carbon into the residual austenite. Such bainite steel has very fine bainite platelets (thickness 100nm or less). In this specification the expression 'Super Bainite Steel' is used for such steel. In particular, the impact of varying the manganese content to achieve fast transformation times, and hence low manufacturing costs without the presence of expensive alloying materials is discussed. In one embodiment of the invention a Super Bainite Steel comprises in weight percent: carbon 0.6 to 1.1 %, silicon 1.5 to 2.0 %, manganese 0.5 to 1.8 %, nickel up to 3 %, chromium 1.0 to 1.5 %, molybdenum 0.2 to 0.5 %, vanadium 0.1 to 0.2 %, balance iron save for incidental impurities. In particular it was noted that excellent properties were obtained if the manganese content is about 1% by weight. Various processes for making the Super Bainite Steel are discussed, but a particularly useful process includes the step of cooling the steel from an austenite quickly enough to avoid transformation to pearlite and transforming the steel to bainite at a temperature in the range 190 DEG C to 2500 DEG C. The patent discusses the impact of changing the transition temperature on hardness, and conclude that the invention can provide a very hard steel (>630HV). It is also noted that suitable pearlite can be produced for cutting drilling and shaping, before final transformation to Super Bainite Steel.
Owner:THE SEC OF STATE FOR DEFENCE IN HER BRITANNIC MAJESTYS GOVERNMENT OF THE UK OF GREAT BRITAIN & NORTHERN IRELAND

Hot rolled dual-phase steel sheets with high stretch-flangeability and manufacturing method thereof

InactiveCN102409245AReduce C and Si contentLow costStretch rateExpansion rate
The invention discloses hot rolled dual-phase steel sheets with high stretch-flangeability and a manufacturing method thereof. The manufacturing method has the following advantages: (1) the contents of C and Si are reduced, Mo is eliminated and defined amount of Cr and P are added, thus substantially lowering the cost and being beneficial to improvement of the surface quality and welding properties of the steel sheets; (2) the continuous casting slabs with medium thickness are adopted, and the walking beam furnace is used as buffer, thus realizing connection of casting machines and rolling machines, which are subjected to confluence and direct hot charging rolling; and high temperature rolling, water cooling+air cooling+water cooling stepped cooling path control technology and medium temperature coiling are adopted, so the sheet shapes are obviously improved, thus improving the stability of the steel sheet properties; and (3) the pearlites are effectively restrained by the advanced thermo mechanical control process and P and Cr microalloying paths, thus promoting generation of soft and hard phase structures of ferrites and bainites (or containing fewer martensites); the crystallite dimensions of the ferrites are 4-10mu m; and the hot rolled dual-phase steel with high stretch-flangeability and tensile strength being not less than 580MPa, stretch rate being not less than 26% and hole-expansion rate being not less than 75% is manufactured.
Owner:SHANDONG IRON & STEEL CO LTD

Green fertilizer capable of improving soil and preparation method thereof

The invention discloses a green fertilizer capable of improving soil and a preparation method thereof. The green fertilizer is prepared from the following raw materials in parts by weight: 30-50 parts of animal giblets, 15-20 parts of wheat bran, 12-18 parts of furfural residue, 10-15 parts of bark, 14-22 parts of Chinese medicine residue, 11-19 parts of manioc waste, 8-16 parts of flax seed meal, 5-10 parts of manganese slag, 5-10 parts of plant ash, 6-12 parts of oyster-shell powder, 10-15 parts of leaf mould, 5-10 parts of crushed crude pearlite, 4-8 parts of cologne acid mother liquor, 10-15 parts of tung greensand, 5-10 parts of stone fine grain, 10-15 parts of modified attapulgite, 3-5 parts of chitin oligosaccharide, 2-4 parts of alum powder, 15-20 parts of ammonium sulfate, 10-15 parts of monopotassium phosphate,1-2 parts of ferrous sulfate, 0.5-1 part of sodium borate, 1-2 parts of zinc sulfate and 0.5-1 part of ammonium molybdate. By adopting the green fertilizer capable of improving soil disclosed by the invention, the organic matter of the soil can be increased, the soil fertility is improved, meanwhile, the soil structure also can be improved, the soil pests are prevented and treated, the phenomena of soil degradation, soil fertility reduction and soil hardening are effectively improved, and healthy and quick growth of green plants is facilitated.
Owner:MINGGUANG HEZHONG IND ENG INSTALLATION

Manufacturing method of low-yield-ratio carbon-manganese low-temperature steel

InactiveCN108220784AReduce manufacturing costReduce the ductile-brittle transition temperatureYield ratioMaterials science
The invention discloses a manufacturing method of low-yield-ratio carbon-manganese low-temperature steel. The chemical components of the low-yield-ratio carbon-manganese low-temperature steel comprises, by weight, 0.05-0.09% of C, 0.10-0.40% of Si, 1.30-1.50% of Mn, less than or equal to 0.010% of P, less than or equal to 0.003% of S, less than or equal to 0.010% of Nb, 0.030-0.060% of Al, and thebalance Fe and inevitable impurities. By adopting the design of low-carbon, high-manganese and high-aluminum components, fine quasi-polygonal ferrites and a few acicular ferrites and pearlitic structures through cooperation of the dynamic soft reduction control technology during the continuous casting process and high-temperature heavy reduction and fast cooling control process after rolling during the rolling process. Compared with steel for liquefied petroleum gas tankers, the low-yield-ratio carbon-manganese low-temperature steel has the characteristics of being pure in steel quality, lowin yield ratio, high in toughness and excellent in low-temperature welding performance. The ductile-brittle transition temperature of a steel plate in the thickness direction is lower than minus 80 DEG C, and the postwelding welding performance at minus 70 DEG C is excellent. Moreover, there is no need to add microalloy elements such as Cu and Cr, and the manufacturing cost is low.
Owner:HUNAN VALIN XIANGTAN IRON & STEEL CO LTD
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