45results about How to "Few defects such as cracks" patented technology

The invention discloses a sol-gel method for preparing micro / nano titanium dioxide and lyophobic film thereof on metal surfaces, which includes the following steps of (a) pretreating metal substrates; (b) preparing micro / nano TiO2 films on surfaces of the metal substrates which are pretreated; and (c) preparing (heptadecafluoro-1,1,2,2-tetradecyl) triisopropoxysilane-silicon dioxide lyophobic films on the micro / nano TiO2 films on the surfaces of the metal substrates. The sol-gel method has the advantages of high operability, simplicity in processing and equipment and easiness in industrialization. Besides, the titanium dioxide films are used as transitional layers so that corrosion of acid sol to the metal substrates during the process of directly coating the silane lyophobic films is avoided, wettability to silane sol is enhanced, and uniform and compact lyophobic films are prepared finally. Meanwhile, defects such as cracking and the like can be reduced by means of multiple coating processes, corrosion resistance performance of the films is improved, surface free energy of the films is decreased by lyophobic treatment, and dirt settled on the films is reduced.

The invention discloses a downward-pushing magnetic material wet molding hydraulic machine and a use method thereof and belongs to the magnetic material wet forming field. The downward-pushing magnetic material wet molding hydraulic machine comprises a downward-pushing pressing structure. The downward-pushing magnetic material wet molding hydraulic machine further comprises a mechanical limiting structure, a packing structure, a blank fetching system, a double-oil cylinder balance system and a mould surface cleaning system; the downward-pushing pressing structure comprises an upper mould seat, a pushing rod, a large-bore oil cylinder, a fixing mould frame and a lower mould hydraulic cylinder, wherein the upper mould seat is driven by the large-bore oil cylinder, the pushing rod is located in the fixing mould frame, and the fixing mould frame is connected with the lower mould hydraulic cylinder, the large-bore oil cylinder and the lower mould hydraulic cylinder are both communicated with a hydraulic station; the mechanical limiting structure includes a horizontal mechanical limiting structure and a longitudinal mechanical limiting structure; the horizontal mechanical limiting structure comprises the pushing rod and the fixing mould frame; a fixing mould cavity is arranged in the fixing mould frame; the pushing rod is located in the fixing mould cavity in the fixing mould frame; and the longitudinal mechanical limiting structure includes a servo motor A and a transmission mechanism. With the downward-pushing magnetic material wet molding hydraulic machine and the use method thereof adopted, product formation error is small, and the pollution source of slurry to hydraulic oil can be eliminated.

The invention provides a precise forging-continuous rolling production technology of a large and heavy single molybdenum rod. The production technology comprises the following steps of: 1, carrying out billet forging on the molybdenum rod by a precision forging machine to obtain a precision forging bar; 2, heating the precision forging bar; 3, rolling for the first time by a Y-shaped three-roller continuous mill to obtain a rolled molybdenum rod; 4, heating the rolled molybdenum rod; and 5, rolling for the second time by the Y-shaped three-roller continuous mill and obtaining the large and heavy single molybdenum rod of which the piece weight is 45-50kg. Deep processing of a molybdenum bar is successfully achieved by setting and optimizing each parameter in precision forging, thermal treatment and continuous rolling processes; the large and heavy single molybdenum rod, which is suitable for subsequent wire drawing, and of which the piece weight is 45-50kg, is finally produced; and the production efficiency is obviously improved. The piece weight of the molybdenum rod produced by the production technology is much greater than that of the molybdenum rod produced by a traditional technology; and the precise forging-continuous rolling production technology has no welding spot on the whole, and is even in internal organization, high in product quality and suitable for large-scale industrial production.

The invention provides an explosive welding method for pre-processing a rare and precious metal composite plate through severe surface deformation. The method includes the following steps that a base material and a composite material are determined, a connecting face of the base material and the composite material is cleaned and processed, severe deformation processing is performed on the connecting face, the connecting face is baked, roughness processing is performed on the connecting face, leveling processing of the connecting face is performed, and explosion welding and cladding and follow-up repair welding, leveling, edge cutting and mechanical polishing are performed, wherein a severe deformation processing method includes rolling, mechanical grinding, mechanical impacting, shot blasting or sand blasting. Before explosive cladding, the severe surface deformation processing is performed on the base material and the composite material, the connecting face can be of a multi-stage micro structure in different sizes, and the defect that cracks and the like happen easily in the explosive cladding process of rare and precious metal can be reduced; and besides, the severe surface deformation induces a large number of crystal structure defects, intermetallic compounds can be reduced, and the interface binding strength is remarkably improved.

The invention relates to a fire resistant brick used for a lining of thermal equipment and a preparation method thereof. The preparation method includes the steps of: 1) employing 5-25 wt% of corundum granules, 5-25 wt% of high bauxite granules, 10-30 wt% of corundum-alloy composite granules and 10-30 wt% of high bauxite-alloy composite granules as aggregates and 10-20 wt% of corundum fine powder and 10-20 wt% of high bauxite fine powder as base materials; 2) mixing the base materials uniformly to prepare a pre-mixed base material; 3) mix-grinding the aggregates with resin to prepare a mix-ground aggregate, and adding the mix-ground aggregate to the pre-mixed base material, grinding the mixture, press-moulding a brick, and performing thermal-treatment at 150-300 DEG C for 12-48 h to prepare the fire resistant brick used for the lining of thermal equipment. The brick can regulate temperature automatically and can stabilize the temperature of a shell of the equipment when environment temperature or medium temperature in the thermal equipment is changed, so that problems of high energy consumption due to overheat of the shell and corrosion on the shell material due to enrichment of low-temperature medium in the shell.

The invention discloses a forming method of a high-thermal-conductivity silicon nitride substrate, and the forming process comprises the following steps: S1, burdening and ball milling: adding an organic monomer and a cross-linking agent into a solvent to prepare a premixed solution, and then mixing the premixed solution, a dispersing agent, silicon nitride and auxiliary ceramic powder for ball milling; and S2, adding a plasticizer to increase the flexibility of the silicon nitride sheet after tape casting. Then carrying out secondary ball milling, wherein the ball milling time is 4-30 hours; s3, vacuum defoaming: performing vacuum defoaming on the slurry obtained by secondary ball milling, and meanwhile, adding an initiator and stirring; s4, gel tape casting: carrying out tape casting operation on the slurry obtained by vacuum defoaming; and S5, drying the thin sheets, namely drying the thin sheets with certain strength and toughness after being cured for a certain time. According to the preparation method, a gel and tape casting combined technology is adopted, the advantages of two types of forming are integrated, the production cost is reduced, the environmental pollution is reduced, and the preparation of the high-performance silicon nitride ceramic substrate is realized.

The invention provides a block alloy high-flux preparation device and method.The block alloy high-flux preparation device is provided with a laser cladding vacuum glove box, a gas quenching furnace, a hydraulic elevator, a powder feeding system and a temperature control system, and the laser cladding vacuum glove box is provided with a laser cladding system and the powder feeding system connected with the laser cladding system; alloy powder is fed into the laser cladding system through the powder feeding system to be subjected to laser cladding treatment, the gas quenching furnace is arranged at the lower end of the laser cladding vacuum glove box and used for base plate preheating and alloy heat treatment, and one side of the gas quenching furnace is connected with the temperature control system and used for controlling the base plate preheating temperature and the alloy heat treatment temperature. And a hydraulic elevator is arranged at the lower end of the gas quenching furnace, and a substrate is fed into the gas quenching furnace and the laser cladding vacuum glove box through the hydraulic elevator. The invention also provides a preparation method thereof. The method can be widely applied to the technical field of alloy material preparation.

The invention discloses a Sm-Gd-Dy tri-rare-earth ion tantalate and a preparation method and application thereof. The general chemical formula of the Sm-Gd-Dy tri-rare-earth ion tantalate is SmGdDy<c>TaO<7>, wherein the a, b and c meet the relationship of a+b+c=3 and are separately in a range of 0.8-1.2. The preparation method comprises the following steps: (1) weighing samarium nitrate, gadolinium nitrate, dysprosium nitrate and tantalum oxalate according to a stoichiometric ratio, performing mechanical mixing with citric acid with a preset amount under a heat preservation condition, adding a concentrated ammonia water neutralization solution during the mixing process, and carrying out mechanical mixing to promote a complexation reaction under a heat preservation condition; and (2)drying the obtained solution, and then carrying out calcination at a high temperature to remove carbon impurities to obtain the Sm-Gd-Dy tri-rare-earth ion tantalate powder. The Sm-Gd-Dy tri-rare-earth ion tantalate has good high-temperature thermal stability and low thermal conductivity, and can be used as a thermal barrier coating material.

The invention discloses a modified concrete expansive agent, made from, by weight, 10-20 parts of calcium silicoaluminate, 25-30 parts of calcium sulfoaluminate, 20-25 parts of sulfur fixing waste residue, 10-20 parts of modified red clay, 1-5 parts of tourmaline powder, 6-8 parts of iron slag, 4-6 parts of modified calcium oxide, 4-6 parts of magnesium oxide, 3-5 parts of sodium methyl silicate, 2-4 parts of calcium formate, 0.1-0.3 part of azodicarbonamide, 0.4-0.7 part of maltodextrin, 1-4 parts of sodium lignin sulfonate, 0.3-0.6 part of polyglycol ether, 1-3 parts of a polycarboxylate superplasticizer, 2-5 parts of modified diatomite powder, and 0.5-0.8 part of nano calcium carbonate. The modified concrete expansive agent has the advantages of high strength, good compensating capacity and the ability to control calcium oxide reaction and is a promising concrete admixture.

The invention provides a precise forging-continuous rolling production technology of a large and heavy single molybdenum rod. The production technology comprises the following steps of: 1, carrying out billet forging on the molybdenum rod by a precision forging machine to obtain a precision forging bar; 2, heating the precision forging bar; 3, rolling for the first time by a Y-shaped three-roller continuous mill to obtain a rolled molybdenum rod; 4, heating the rolled molybdenum rod; and 5, rolling for the second time by the Y-shaped three-roller continuous mill and obtaining the large and heavy single molybdenum rod of which the piece weight is 45-50kg. Deep processing of a molybdenum bar is successfully achieved by setting and optimizing each parameter in precision forging, thermal treatment and continuous rolling processes; the large and heavy single molybdenum rod, which is suitable for subsequent wire drawing, and of which the piece weight is 45-50kg, is finally produced; and the production efficiency is obviously improved. The piece weight of the molybdenum rod produced by the production technology is much greater than that of the molybdenum rod produced by a traditional technology; and the precise forging-continuous rolling production technology has no welding spot on the whole, and is even in internal organization, high in product quality and suitable for large-scale industrial production.

A cutting method employing a laser (11). Before a laser (11) has been used to perform a cutting operation, a heat absorption layer (20) is laid over a cutting path on a substrate to undergo a cutting operation, such that when the laser (11) cuts the substrate (10) along the cutting path on the substrate (10), the heat absorption layer (20) can partially absorb heat of the laser (11), thereby reducing a temperature gradient between a cut section and a non-cut section surrounding the cut section on the substrate (10) during cutting, reducing generation of heat stress and formation of defects, such as cracks, and providing a product of good quality.

The invention discloses a method for pressing and forming a refractory box, which comprises the following steps: distributing refractory box powder according to a preset height into a mold cavity formed by a mold frame, a bottom lower mold core and a side lower mold; the bottom lower mold core and the side lower mold The mold divides the refractory box powder located above it into a bottom powder aggregate and a side powder aggregate; the upper mold core is pressed down to the mold cavity, and the bottom lower mold core moves downward, so The side lower mold is lifted upward, and the refractory box is formed by the relative movement of the upper mold core, the bottom lower mold core and the side lower mold; during and after the pressing process, the bottom powder aggregate and the side powder aggregate are aggregated. The compression ratio of the body remains the same. Correspondingly, the present invention also discloses a press-forming device for a refractory box and a refractory box. The implementation of the present invention can effectively improve the uniformity of different positions of the refractory box, prevent its forming and fracture, and reduce defects such as forming cracks.

The invention discloses a semi-continuous casting process of a large-diameter medium-strength heat-resistant magnesium alloy, and the alloy composition (wt.%) aimed at is: Al? 7.5-9.0%, Ag? 0.02-0.80%, Zn? 0.35-0.55%, Mn? 0.05-0.20%, RE? 0.01-0.10%, Ca? 0.001-0.020%, the rest is Mg and non-removable impurity elements. The process includes the steps of melting raw materials at 620-680°C, ventilating and stirring, raising the temperature to 720-740°C for 10-20min, standing at 680-700°C for 1-3h, and casting at low temperature. By adjusting the process parameters of each step, a magnesium alloy ingot with a diameter of Ф330-630mm and a length of ≥1000mm was successfully cast. Large-diameter, high-quality ingots can provide high-quality blanks for the forming of large-scale structural parts, which is of great significance for promoting the wide application of magnesium alloys.

The invention provides a method for preparing 24CrNiMo bainite alloy steel by laser selective melting technology. The method includes scanning the 24CrNiMo alloy steel powder spread on the substrate according to the preset laser selective melting scanning path until the powder is melted. A step of. In the present invention, by optimizing the process parameters and using the effects of alloy elements such as C, Cr, Ni, Mo, etc., the bainite alloy steel with uniform structure is obtained under the high cooling rate of laser selective melting, and the average microhardness of the obtained bainite structure is It reaches 330-346HV, the tensile strength is 962-978Mpa, the elongation is 16.4-17.6%, and the strong-plastic product reaches 16.1-16.9Gpa·%. The tissue has excellent strength and toughness matching. The method and process are mainly used for laser selective melting manufacturing of 24CrNiMo alloy steel high-speed rail brake discs.

The invention belongs to the technical field of carbon foam preparation, and in particular relates to carbon foam and a preparation method thereof. The present invention uses lignite thermally soluble catalytic heavy components as raw materials, and the prepared foamed carbon is not prone to cracks, has uniform cell size, high compressive strength, good mechanical properties and heat insulation performance, no additives are needed, and pressure relief is controlled. The speed can improve the yield of foamed carbon and the uniformity of the large size of the cells, reduce the probability of defects such as cracks in the foamed carbon, and is conducive to obtaining foamed carbon with uniform cells and higher mechanical properties, and avoiding the rapid pressure release of foamed carbon. The uneven size of the cells makes the carbon foam prone to microcracks and reduces the mechanical properties of the carbon foam; in addition, the present invention can also avoid the rapid increase of the temperature of the system by tens of degrees Celsius caused by rapid pressure release, which causes more defects in the carbon foam question.

The invention discloses a method for preparing a low-cost, high-strength and tough titanium alloy pipe for marine engineering. The method comprises the following steps: first, performing conventional forging and precision forging deformation on an ingot of titanium alloy to obtain a bar blank; The billet is cross-rolled and pierced, and then subjected to surface defect trimming, pickling and annealing to obtain a perforated tube blank; 3. Cold-rolling the perforated tube blank to obtain a cold-rolled tube blank; Pickling, heat treatment and straightening to obtain titanium alloy pipes. In the invention, the titanium alloy ingot is prepared into a bar billet by conventional forging and precision forging, and then a tube billet is obtained by skew rolling, piercing and cold rolling, and finally heat treatment is performed to obtain a titanium alloy pipe, which shortens the technological process and reduces the processing time. Compared with traditional titanium alloy pipes, the cost and cost are greatly reduced, and at the same time, it provides a guarantee for the microstructure and properties of the pipes after forming. The prepared titanium alloy pipes not only meet the conditions of offshore operation, but also meet the environmental requirements of oil and gas development and service.