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522results about How to "Fine and uniform grain" patented technology

Micro-alloying steel for oil gas transport seamless pipeline and its preparation method

The invention discloses micro-alloying seamless pipeline steel and process for preparation. According to weight percentage, the range of the chemical components of the invention includes that C holds 0.08% to 0.20%, Si is equal to or less than 0.04%, Mn takes 0.60% to 1. 50%, S is equal to or less than 0.015%, P is equal to or less than 0.025%, Al is equal to or less than 0.04%, Ti is equal to or less than 0.04%, H is equal to or less than 2.5*10-4%, O is equal to or less than 25*10-4%, the rest is Fe and unavoidable foreign matters. The process for preparation comprises technique steps, including smelting, refining, continuous casting, hot rolling and slow cooling. Round steel with the size of phi 70 to 150 millimeters can be produced by the process for preparation. The seamless pipeline steel of the invention has perfect anti-sulphide stress corrosion (SSC resistance) capability and anti-HIC property. The pipeline steel which can substitute for welding pipe can be utilized in the filed of oil pipeline and the like, and the invention increases the reliability of material and adaptability of variety, in particular being adaptable for the low submarine temperature and corrosion-resistant environment and for manufacture of thick-walled tubes.
Owner:LAIWU IRON & STEEL GRP

Superfine crystal nickel-based high-temperature alloy and method for preparing same

The invention provides an ultra-fine crystalline nickel base high-temperature alloy and a method for preparing the same, belonging to the high-temperature alloy steel field. The ultra-fine crystalline nickel base high-temperature alloy is particularly applicable to a high-temperature structural component which has high requirement to high-temperature strength and fatigue property, requires superplastic forming and has a complicated structure. The chemical compositions by weight percent of the ultra-fine crystalline nickel base high-temperature alloy are: 17 to 19 percent of Fe, 17 to 20 percent of Cr, 2.8 to 3.3 percent of Mo, 0 to 1.5 percent of W, 0.8 to 1.5 percent of Al, 0.3 to 1.3 percent of Ti, 4.7 to 5.7 percent of Nb, less than or equal to 0.015 percent of C, and the balance being Ni. The preparation method reasonably controls the parameter of a deformation process to allow the deformation temperature to be positioned in a grain boundary precipitated phase region and an austenite phase region which have higher solution temperatures, and uses powerful pinning action of a precipitated phase to the grain boundary to produce the ultra-fine crystalline alloy with a grade of grain fineness of between ASTM12 and ASTM13 grade. Compared with the prior art, the ultra-fine crystalline nickel base high-temperature alloy has simple alloy compositions, greatly reduces the resistance to deformation during forming, has small loss to forging and rolling equipment, and prevents crystal grains from growing when the ultra-fine crystalline nickel base high-temperature alloy is heated for a long time at a high temperature.
Owner:UNIV OF SCI & TECH BEIJING

High-temperature, high-strength and low-carbon hot work die steel and preparation method thereof

The invention discloses hot work die steel capable of being used for a long term at the working condition of 600-700 DEG C and belongs to the field of material and preparation. The hot work die steelcomprises the following components in percentage by mass: 0.12-0.30 of C, equal to or less than 0.5 of Si, equal to or less than 0.5 of Mn, 1.0-3.0 of Cr, 1.5-2.5 of Mo, 0.3-1.2 of W, 0.5-1.6 of Ni, 0.2-1.0 of V, 0.03-0.15% of Nb, equal to or less than 0.05 of N, equal to or less than 0.03 of S, equal to or less than 0.03 of P, equal to or less than 3.5 of (Mo+W), equal to or less than 1.0 of (Nb+V) and the balance of Fe and unavoidable impurity elements. According to the hot work die steel, low carbon is adopted to form lath martensite so as to obtain high tenacity at room temperature and lowtemperature; through alloying of Cr, W, Mo, V, Nb and the like and the thermal deformation optimization and thermal treatment technology, solution strengthening is improved and MC and M2C type carbide still keeping stability at 600-700 DEG C is formed so as to obtain high temperature strength and thermal stability of the material. Compared with the commonly used hot work die steel at present including H13, 25Cr3Mo3NiNbZr and the like, the high temperature strength at 700 DEG C of the hot work die steel is improved by 50-100%, the tempering thermal stability is improved by 50-100%, the problemabout hot work die steel used at 600-700 DEG C is better solved, and the hot work die steel has longer service life at 600 DEG C and below.
Owner:UNIV OF SCI & TECH BEIJING

La doped SrTiO3 base oxide pyroelectric material and preparation method

A La-doped strontium titanate (SrTiO3)-based oxide thermoelectric material and a preparation method thereof, belonging to the technical field of energy materials. The method is divided into two parts of powder synthesis and forming of bulk materials. The powder synthesis adopts the sol-gel method, takes tetrabutyl titanate, strontium nitrate and lanthanum nitrate as raw materials, takes deionized water and ethanol as solvents and takes acetic acid and glycerol as a catalyst and a chelating agent to prepare SrTiO3 gel with different La doping amount, and the temperature is kept at the temperature of 500-560 DEG C for 1-2 hours to obtain precursor powder. The bulk forming adopts the spark plasma sintering method, and the sintering conditions are as follows: the vacuum degree is 2-10Pa, the pressure is 40-50MPa, the heating rate is 100 DEG C/min, the sintering temperature is 900-1000 DEG C, and the holding time is 5-10min. The method synthesizes the La-doped SrTiO3-based bulk thermoelectric material with high chemical homogeneity, uniform and fine grains and single-phase perovskite structure under the conditions of lower reaction temperature and shorter reaction time. The preparation method has the advantages of simple and convenient process, short synthesis and forming time, and the like.
Owner:UNIV OF SCI & TECH BEIJING

Method for preparing spinel lithium titanate of cathode material of lithium ion battery

The invention relates to a method for preparing a cathode material Li4Ti5O12 of a high-performance lithium ion battery. The method comprises the following steps of: adopting the combined method of sol-gel and microwave treatment to prepare micro powder of nano-class Li4Ti5O12, and simultaneously modifying Li4Ti5O12 by carbon doping and metallic doping. The method utilizes the sol-gel method to effectively control chemical composition, phase composition and powder size of the Li4Ti5O12, thereby improving the uniformity and the electric conductivity of the Li4Ti5O12; simultaneously by utilizing the characteristics of the microwave technique of quick temperature rise, even heating and conglobation resistance, the high-power industrial microwave oven is used for treatment, so that the treatment time of the Li4Ti5O12 is greatly shortened, the yield is greatly improved, and the cost and the energy consumption of the material are reduced, the process is simplified, the efficiency on the industrialized production of the lithium ion battery is improved, and the industrialized application is easily achieved; and by doping carbon and metallic elements, the electric conductivity of lithium iron phosphate is greatly improved, and the charging and discharging capacities and the cycle index of the lithium iron phosphate are simultaneously and effectively increased.
Owner:ZHENGZHOU UNIV +1

Vacuum freeze drying method and vacuum freeze dryer

The invention provides a vacuum freeze dryer which comprises a material box, a water catching bin, a refrigerating unit, a heater, a vacuum pump and a control device. The material box is communicated with the water catching bin. The water catching bin is connected with the vacuum pump. The refrigerating unit and the heater are arranged outside the material box. The control device controls the refrigerating unit, the heater and the vacuum pump. The material box is internally provided with a refrigerating pipe and a heating pipe at the same time, and the refrigerating pipe and the heating pipe are used for freezing and drying materials respectively. The inner wall of a material frame and the inner wall of the material box are each provided with a temperature sensor, and the temperature sensors monitor the temperature of the material frame and the temperature of the material box. Materials inside a material bottle are frozen in advance to reach the eutectic point approximately, then the temperature is decreased rapidly, and the materials pass through the eutectic point within the short time as little as possible, so that the grain size of crystals is effectively controlled, the fine freeze-drying powder is obtained, and the freeze-dried powder product quality is improved. The freezing cavity and the drying cavity are integrated, the technological steps are simplified, the occupied space is small, and refrigerating and heating are uniform.
Owner:BEIJING HAIHETIAN TECH DEV

Method for rapidly preparing zirconium carbide ceramics powder

The invention relates to a preparation method of zirconium carbide ceramics powder; the method for rapidly preparing zirconium carbide ceramics powder is characterized in that: the method comprises the following steps: 1) raw material selection: the raw materials are selected according to 12:4-12:5 of mass ratio of zirconium propoxide solution and sugar and 8:32:1:1-8:64:2:4 of volume ratio of zirconium propoxide solution, normal propyl alcohol, chelant-acetic acid and water; the solvent acetic acid is selected according to (7-8)g:50ml of proportion of the sugar and the solvent acetic acid; 2) the preparation of dried gel power; 3) preparation of precursor powder; 4) heat treatment of the precursor powder; carbothermal reduction reaction is carried out under the conditions of high heating rate and short temperature preservation time, the synthesizing process of the zirconium carbide powder is shortened into dozens of minutes even several minutes, so as to obtain high-purity and refined zirconium carbide ceramics powder with good sintering character; single zirconium carbide phase can be analyzed by X-ray diffraction, the oxygen content in the product is 0.5-3 percent, and the free carbon content is from 0.2 to 2 percent; the crystal particles are uniform and tiny, and the mean grain size is less than 500nm.
Owner:WUHAN UNIV OF TECH

Wide-temperature, high-frequency and low-loss manganese-zinc soft magnetic ferrite material and preparation method thereof

A wide-temperature, high-frequency and low-loss manganese-zinc soft magnetic ferrite material comprises a main component, an auxiliary component A and an auxiliary component B, wherein, according to weight percentage, the main component comprises Fe2O3, MnO and ZnO; based on the weight of the main component, the auxiliary component A comprises at least two of CaCO3, V2O5, TiO2 and Co3O4, and the auxiliary component B comprises at least three of CaCO3, Nb2O5, TiO2, Co3O4, CuO, MoO and SiO2; the SiO2 amount in the auxiliary component B is determined according to the total amount of SiO2 impurities in the main component so as to ensure that in the whole material, the SiO2 amount is 0.025-0.035% of the total weight of the main component. A preparation method of the wide-temperature, high-frequency and low-loss manganese-zinc soft magnetic ferrite material sequentially comprises the following steps: performing component analysis on the main component, primarily dosing, primarily sanding, presintering, secondarily dosing, moulding and sintering. The wide-temperature, high-frequency and low-loss manganese-zinc soft magnetic ferrite material has excellent working performance under the conditions of 500KHz and 50mT and within the temperature range from -20 DEG C to 120 DEG C, has relatively low loss, saves more energy than the conventional material, and has lower standby loss at low temperature and room temperature.
Owner:郴州市久隆旺高科电子有限公司

Gear steel 20CrMoSH and technology for improving hardenability stability thereof

The invention discloses gear steel 20CrMoSH and a technology for improving the hardenability stability thereof. The technology comprises the procedures of converter smelting, LF refining, RH refining,continuous casting, heating and rolling. The gear steel is prepared from the chemical components, by weight, 0.19%-0.21% of C, 0.20%-0.26% of Si, 0.64%-0.70% of Mn, 1.00%-1.06% of Cr, 0.15%-0.21% ofMo, 0.015%-0.025% of S, smaller than or equal to 0.018% of P, 0.015%-0.025% of Als, smaller than or equal to 0.03% of Ni, smaller than or equal to 0.03% of Cu, smaller than or equal to 0.0015% of O and the balance Fe and unavoidable impurities. According to the gear steel 20CrMoSH which is produced through the method and has the diameter phi ranging from 28 mm to 50 mm, the hardenability J1.5 ranges from 40 HRC to 45 HRC, the hardenability J5 ranges from 37 HRC to 42 HRC, the hardenability J9 ranges from 28 HRC to 33 HRC, and the maximum discrete value of the hardenability of the steel in thesame furnace is not larger than 3 HRC. The heat-treatment deformation of a gear can be significantly reduced by means of high-stability hardenability, and therefore the meshing precision of the gear is improved. The method is low in cost and high in production efficiency, and the product has the advantages that the hardenability is stable, the gear heat-treatment deformation is small, and the machined gear is high in meshing precision and low in service life.
Owner:HANDAN IRON & STEEL GROUP +1

High-strength thick steel plate with excellent crack-arrest property and manufacturing method thereof

The invention relates to a high-strength thick steel plate with an excellent crack-arrest property. The steel plate has the following characteristics: a wide-plate tensile value Kca for determining the crack-arrest property is larger than 6000 N/mm<1.5>; yield strength at the positions, which are respectively 1/4 and 1/2 the thickness of the steel plate away from the surface of the steel plate, isno less than 460 MPa; tensile strength is 570 to 720 MPa; Charpy impact energy at minus 40 DEG C is no less than 200 J; and a zero-ductility transition temperature is less than minus 60 DEG C. The steel plate provided by the invention comprises the following components by weight: 0.04 to 0.16% of C, 0.1 to 0.5% of Si, 0.9 to 1.6% of Mn, 0.1 to 0.3% of Cu, 0.2 to 0.9% of Ni, no more than 0.02% ofP, no more than 0.02% of S, 0.01% to 0.05% of Als, 0.002 to 0.010% of N, 0.02% to 0.05% of Nb and 0.01 to 0.03% of Ti, with the balance being Fe and unavoidable impurities. According to the invention,through optimization of chemical components of a high-strength steel plate and adoption of controlled rolling and controlled cooling processes for controlling the microscopic structure and grain sizein a plate thickness direction, the crack-arrest steel plate with high yield and stable strength and toughness is obtained. The high-strength thick steel plate provided by the Invention is used as container vessel steel, and has the characteristics of excellent crack-arrest toughness, high yield strength, excellent low-temperature toughness and large thickness.
Owner:ANGANG STEEL CO LTD
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