172results about How to "No shrinkage cavity" patented technology

The invention provides a gray pig iron, which comprises the following elements in percentage by weight: 3.1 to 3.4 percent of C, 1.5 to 2.1 percent of Si, 0.5 to 0.8 percent of Mn, 0 to 0.06 percent of P, 0.05 to 0.15 percent of S, 0.15 to 0.50 percent of Cr, 0.3 to 0.8 percent of Cu, 0 to 0.12 percent of Sn, 0.20 to 0.60 percent of Ni, and the balance of Fe. In the production process of the gray pig iron, the Cu, the Cr, the Ni and the Sn are added into molten iron to perform alloying, so the defect of large shrinkage porosity tendency caused by using molybdenum to perform the alloying can be overcome, the obtained gray pig iron has excellent casting property, shrinkage cavities are not generated on casts, the requirements on materials of key casts of cylinder bodies and cylinder covers of high-performance engines at present can be met; and the price the Ni and the Sn is lower than that of the molybdenum, so the cost of the casts is low.

The invention relates to a preparation method of a graphene-reinforced aluminum matrix composite. Aiming at the conditions that graphene is nonuniformly dispersed in an aluminum alloy matrix and is difficult to combine with the matrix, the preparation method adopts a semi-solid squeeze casting method, and comprises the steps of smelting in a smelting and stirring atmosphere oven, electromagnetically stirring, pouring, and conducting squeeze casting to obtain the graphene-reinforced aluminum matrix composite. The preparation method is advanced in process, accurate and detailed in data, and precise in process; a slurry is pure; a metallographic structure is good in compactness without the phenomenon of shrinkage porosity; the prepared graphene-reinforced aluminum matrix composite has the hardness reaching to 87 HB, the tensile strength reaching to 255 MPa, the elongation reaching to 8%, and the compactness reaching to 99.6%; and the preparation method is the advanced preparation method of the graphene-reinforced aluminum matrix composite.

The invention discloses a riser heating and insulating agent, which comprises the following components in percentage by weight: 5 to 35 percent of Al, 10 to 25 percent of AlN, 3 to 20 percent of low-carbon graphite, 5 to 25 percent of magnesia-alumina spinel, 5 to 15 percent of quartz, 10 to 30 percent of ferric oxide powder, 5 to 20 percent of corundum, 5 to 10 percent of organosilicon phlogopite, and 1 to 10 percent of MgO; and the riser heating and insulating agent is prepared by the following processes: crushing, pulverizing, mixing, pelletizing, drying, and the like. The riser heating and insulating agent has double effects of heating and insulating, and has good insulating effect. Because the riser heating and insulating agent has a granular appearance, dust and smoke are not generated in the using process, and the environment is not polluted. Due to the adoption of the low-carbon graphite, castings do not have carburizing phenomenon, and the molten steel is not polluted. The riser heating and insulating agent is particularly applied to open risers of low carbon steel large-scale steel castings and stainless steel castings with the weight of over 80 tons.

The invention discloses a gray cast iron and a production method thereof. The gray cast iron comprises the following chemical components in percentage by weight: 3.1-3.3% of C, 1.8-2.2% of Si, 0.5-0.8% of Mn, 0-0.04% of P, 0.05-0.1% of S, 0.1-0.4% of Cr, 0.3-0.5% of Cu, 0-0.06% of Sn, Sb less than 0.02%, and the balance amount of Fe. The gray cast iron disclosed by the invention is suitable for producing casting parts which easily shrunk, have thick walls, and have marks above HT300; according to the production method of the gray cast iron, the technical means of adding copper, chrome, antimony and tin in molten iron for alloying in the gray cast iron production process is adopted, so that molybdenum and nickel for alloying in the prior art are replaced, thereby solving the problem of high possibility of shrinkage and looseness of gray cast iron products, after the prepared gray cast iron is used for casting and forming, the casting parts have low possibility of shrinkage and looseness, have no shrinkage hole, have high yield and are low in production costs.

A high-temperature-resisting coating and its production are disclosed. The coating consists of solid material and liquid material. The solid material comprises yttrium oxide, jargonia, rare-earth mixture, glass flour, sodium silicate and active clay and the liquid material consists of borax, sodium hydrate, water glass and water. It has better high-temperature-resisting, oxidation-resisting, anti-corrosive performances and excellent adhesion. It can be used for metal industrial furnace coating.

A technology for casing the high-Mn steel frog of combined switch for railway features that the ferrochromium sand is used as surficial sand and core sand, the alkaline Mg sand powder paint is coated on the surfaces of moulding cavity and core, and an easily cutting plate is added under the insulating siser head. It includes such steps as applying the insulating and heat generating agent to the surface of riser head, horizontal pouring, cutting off the riser head, burying it is sand, and heat treating.

Provided are a composite profiled pipeline and a manufacturing method thereof. The composite profiled pipeline is a nonstandard pipeline and composed of an outer layer and an inner layer of a pipeline, wherein ceramic particle prefab bodies combined with the inner layer of the pipeline in casting mode are distributed in the inner layer of the pipeline at intervals, and the outer layer and the inner layer of the pipeline are combined in metallurgical mode. According to the composite profiled pipeline, the inner wall of the composite profiled pipeline has excellent abrasion performance, the outer wall of the composite profiled pipeline has good weld-ability, bonding properties of an interface between the inner wall and the outer wall of the composite profiled pipeline are good, and simultaneously cast infiltration properties among base metal and the ceramic particle prefab bodies are good, and therefore the base metal and the ceramic particle prefab bodies are firmly combined and difficultly to fall off, and the composite profiled pipeline is long in service life. Furthermore, the base metal in the inner layer of the pipeline can support the ceramic particle prefab bodies well, ceramic particles in the ceramic particle prefab bodies gradually protrude to bear main attrition during the wearing process and thereby effectively prevent surrounding base metal from being further abraded, and the composite profiled pipeline further has the advantages of being simple in structure and manufacture process, adjustable in structure and the like.

The invention provides an epoxy powder primer used for anticorrosion paint for outer walls of deep sea oil transportation steel pipes and a preparing method thereof. The epoxy powder primer comprises following raw materials by mass: 40-50 parts of E-12 epoxy resin, 10-25 parts of linear phenolic epoxy resin, 25-45 parts of a filler, 9-15 parts of a curing agent, 0.1-1 part of an antioxidant, 0.2-1 part of a coupling agent, 0.9-1.8 parts of benzoate, 0.3-1 part of a levelling agent, 1-3 parts of graphene, 1-2 parts of polyvinyl butyral, 3-5 parts of modified polytetrafluoroethylene wax micropowder, 0.2-0.4 part of rare earth chloride and 1-3 parts of pigment. The epoxy powder primer has excellent wear resistance, resistance to pressure, bending resistance and impact resistance, is excellent in adhesion force and fraction of coverage for steel pipes, and can effectively protect the steel pipes from being corroded by various corrosive media in sea water for a long term.

The invention relates to a die-casting method of a graphene enhanced aluminum based composite material, and aims at solving the problems of nonuniform dispersion and difficult combining with a substrate of graphene in an aluminum alloy substrate. A semi-solid die-casting method is adopted, the graphene enhanced aluminum based composite material is prepared through melting, heat preserving, electromagnetic stirring, tamping and die-casting. The method has the advantages that the technology is advanced, data is accurate and real, procedures are strict, slurry is purified, metallographical structure compactness is good, hole shrinkage and loosening are prevented, the hardness of the prepared graphene enhanced aluminum based composite material reaches up to 85 HB, the hardness is improved by 66% compared with the substrate, the tensile strength reaches up to 8%m the tensile strength is improved by 5% compared with the substrate, the compact degree reaches up to 99.6%, and the preparation method of the graphene enhanced aluminum based composite material is advanced.

The invention discloses a hydraulic pump body casting process, the process steps are as follows: moulding-casting material pretreatment-melting-spheroidizing treatment-pouring-heat treatment-stabilizing treatment-gas nitriding treatment-machining-inspection and storing-finished product; and the casting process is simple and practical, and low in cost, the casted hydraulic pump body is dense in tissue, free of shrinkage porosity and cavity, white cast and crack defects, good in tensile strength, and high in hardness.

The invention relates to a magnesium-based composite material semi-solid indirect extrusion casting forming method. According to the magnesium-based composite material semi-solid indirect extrusion casting forming method, in order to solve the problems that wettability is poor between reinforcing body particles and matrix material, agglomerate is prone to be generated, distribution is uneven, anda prepared casting is low in performance, magnesium-zinc-yttrium quasi-crystals with high hardness, high elasticity and good binding property with a matrix are added to a magnesium alloy matrix and used as a reinforcing body, the casting is obtained through smelting in a vacuum atmosphere smelting furnace, ultrasonic-assisted vibration stirring in a composite stirring furnace and indirect extrusion casting, and therefore the mechanical property of the casting is improved; the machining method is advanced in process, data are accurate and detailed, the metallographic structure of the casting isgood in compactness, and defects of shrinkage cavity and shrinkage porosity do not exist; and the initial phase in the metallographic structure is composed of spherical and near-spherical grains, dendritic grains basically disappear, the grain size is obviously refined, tensile strength reaches 225 Mpa, the elongation rate is 6.5%, and hardness reaches 86 HV, so that the method is advanced.

The production process of wheel rim with high quality steel includes sawing blank, heating, punching hole and rolling to form while constant forging and extrusion, cutting, inspection and storing. The wheel rim produced through the said process has no faults of loose internal structure, shrinkage cavity, quenching crack, etc. and has long service life and low production cost.

The invention discloses a split type mould used for a press, a manufacturing method and a forging bucket tooth thereof, which utilizes the split type mould to solve the technical problem of demoulding. The adopted mould is divided into an upper separated body and a lower separated body, the upper separated body consists of a punch head upper cover and a punch head embedded at the lower end of the punch head upper cover; the lower separated body is formed by that an outer sleeve is fixedly connected on a backing plate and internally installed with a tube mold of the separated body, and a disconnecting square sleeve is installed at the upper part inside the tube mold; and an ejector rod is installed in the central hole of the backing plate. The manufacturing method comprises the following steps: the punch head is utilized for hammering the blank so as to carry out foring compression in the tube mold, the punch head moves upwards when the press returns to the original position, the disconnecting square sleeve prevents the forging bucket tooth form moving so as to disconnect the punch head and the forging bucket tooth, the ejector rod ejects the forging bucket tooth and the tube mold of the separated body upwards, the tube mold is divided into two blocks along the outer sleeve, and the forging bucket tooth carries out demoulding automatically. The invention solves the problem of the automatic demoulding of the bucket tooth by foring compression; the mechanical property and the wear-resisting property of the forging bucket tooth are improved by more than 30 percent compared with that of a casting bucket tooth, especially when being used in severe conditions such as mines and the like, the forging bucket tooth has more superior performances.

The invention provides a method for preparing a waterborne plastic toy paint. The paint comprises the following components in percentage by weight: 50 to 70 percent of copolymer emulsion A of butyl acrylate, styrene and acrylonitrile, 10 to 15 percent of copolymer emulsion B of methyl methacrylate, styrene and N-methylol acrylamide, 2 to 5 percent of propylene glycol butyl ether film forming auxiliary agent, 5 to 7 percent of mono-isobutyric acid trimethyl pentanediol ester film forming auxiliary agent, 0.1 to 0.4 percent of polysiloxane and polyester copolymer leveling agent, 0.1 to 0.4 percent of polysiloxane mixture defoaming agent, 0.1 to 0.4 percent of associative type polyurethane thickener, 0.1 to 0.4 percent of 2-amino-2-methyl-1-propanol organic amine neutralizer, 2 to 6 percent of hard polyethylene wax emulsion, 0 to 15 percent of deionized water and 0 to 25 percent of color paste; and the preparation method comprises the following steps of: adding all the acrylic acid emulsion, deionized water, organic amine neutralizer, leveling agent, defoaming agent, film forming auxiliary agents and wax emulsion to a paint mixing kettle with stirring at a rotary speed of 60 to 120rpm, stirring the mixture at a rotary speed of 200 to 300rpm for 10 to 20min, adding the color paste to the mixture at a rotary speed of 60 to 120rpm, stirring the mixture at a rotary speed of 200 to 300rpm for 10 to 20min, adding the thickener until the viscosity of the mixture meets the index of 70 to 110s(paint-1 cup) and the adhesive force of the spraying plate paint film reaches the first grade(by the cut test on an ABS plate), and filtering and packaging.

The invention belongs to the field of engineering machinery, and particularly relates to an integral casting digging bucket and a manufacturing method thereof. The integral casting digging bucket comprises a lifting lug, a top plate, two side plates and a bottom plate connected with the two side plates, and the lifting lug, the top plate, the two side plates and the bottom plate are integrated. Cast steel for casting the digging bucket comprises the following components: 0.1%-0.6% of C, 0.2%-0.6% of Si, 0.5%-1.8% of Mn, 0.5%-1.6% of Cr, 0.2%-0.75% of Ni, 0.1%-0.6% of Mo, less than or equal to 0.035% of P, less than or equal to 0.035% of S, and the balance of iron. The method for manufacturing the integral digging bucket of an excavator by using the cast steel comprises the following steps: smelting the components of the cast steel in a smelting furnace; and after smelting is finished, carrying out modification treatment in front of a furnace, manufacturing models and mould plates, coating, heating, vacuumizing, placing a sandbox, adding sand, modeling, carrying out mould assembling, pouring, quenching, and tempering and cooling to the normal temperature to finish casting of the digging bucket. A vacuum sealing technology and a low alloy steel material are adopted, the integral casting digging bucket is formed by one-time pouring, and the product is high in strength, high in wear resistance, corrosion resistance and impact force resistance and long in service life.

The invention relates to a two-fluid bimetal compound poured crushing hammer manufacturing method. The method comprises the steps that casting is conducted, specifically, a hammer handle pouring system and a hammer pouring system are arranged on a sand mold; high-chromium cast iron and low-carbon alloy steel are smelted, a hammer handle part adopts a low-carbon alloy steel material, and a hammer part adopts a high-chromium cast iron material; a hammer handle is poured at first, according to the weight of the hammer, after 3-15 seconds, a binding agent is added to the low alloy steel liquid surface of a sand mold cavity, and then high-chromium alloy is started to be poured; after pouring is completed, still standing is conducted, after molten steel is cooled and solidified, a semi-finished compound hammer can be obtained; and the semi-finished compound hammer is subjected to heat treatment, and the compound hammer product is obtained finally. By adding the binging agent in the process, a fusion layer which is compact in structure, free of shrinkage cavities, loose and high in strength is formed on an interface of two metals, and the binding strength of the two metals is improved.

A method for preparing a magnesium alloy ingot comprises the following steps of: mixing ingredients, placing dried burdens into a crucible, placing the crucible into an electric resistance furnace for smelting, and introducing mixed gas to protect the melt; controlling the temperature rising speed by a sectional temperature rising method; moving the crucible into a pre-heated solidification system; turning off the power of the solidification system, increasing the content of SF6 in the protective gas, and discharging cooling water to the solidification system to cool the crucible; closing the cooling water and protective gas when the temperature of a drain pipe of the cooling water reaches the room temperature; and taking out the ingot after the ingot is naturally cooled to the room temperature. A solidification system is provided. A temperature-control thermolelectric couple is arranged in a furnace shell; a sprinkler is arranged at the bottom inside the furnace shell; and a protective gas inlet pipe is arranged on a thermal insulation cover of the crucible. High-temperature magnesium alloy melt can be prevented from being oxidized and burnt; no heat loses from the side of the crucible and the temperature is controlled precisely, so that orientated solidification can be implemented and the magnesium alloy ingot which has high surface and internal quality can be obtained.

The invention relates to ink and in particular relates to water-based nano pigment ink for textile printing. According to the formula, the ink mainly comprises the following components in parts by weight: 12.4-18.6 parts of water-based pigment slurry, 9.5-14.9 parts of a water-based resin, 5.3-9.6 parts of a quick-dry type solvent, 5.4-9.8 parts of a moisturizing solvent, 0.5-2 parts of a surfactant, 0.05-0.2 part of an antibacterial agent and 50.9-65.55 parts of deionized water. According to the ink disclosed by the invention, textiles do not need to be preheated and heated, and the ink refers to healthy and environment-friendly water-based nano pigment ink which can be directly printed on the textiles. Moreover, a digital ink-jet printing textile prepared by the ink has excellent color fastness to washing, color reduction rate and excellent handfeel.

The invention provides a hot-dipping Zn-Al-Mg coating steel plate with an excellent dip plating performance, and a production method. A coating contains 1 to 5 percent of Al, 1 to 3 percent of Mg, less than or equal to 0.0104 percent of Fe, 0.1 to 1 percent of Si, 0.01 to 1 percent of Ce, and the balance Zn and inevitable impurities. Compared with the prior art, according to the hot-dipping Zn-Al-Mg coating steel plate with the excellent dip plating performance, and the production method provided by the invention, through designing the plating solution element content, adding 0.1 to 1 percentof Si and 0.01 to 1 percent of Ce, and controlling Al to be 1 to 5 percent, the infiltrating performance of a plating solution and a substrate is improved, and a large number of iron elements are prevented from being brought into zinc liquid so as to cause an adverse effect, so that the coating is uniform and fine in microstructure. The designed plating solution adapts to a steel plate for a common household appliance and has a good infiltrating effect on the surface of the steel plate; and in addition, through optimizing annealing and hot-dipping processes, the coating formed on the surface of the steel plate is fine and uniform in microstructure without skip plating or shrinking and is remarkably improved in pitting corrosion resistance.

The invention provides a gypsum model precise casting technology and relates to the technical field of casting technologies. The gypsum model precise casting technology comprises the following steps that gypsum slurry is prepared; grouting is carried out, a box frame in which a module is installed is placed into a grouting chamber, then vacuumizing is carried out to 0.05-0.06 MPa, and the slurry is stably poured into the box frame; roasting is carried out, step temperature rise is adopted, and heat is preserved for a certain period of time in each section, so that the temperature of the innerwall and the temperature of the outer wall are consistent; casting and casting cleaning are carried out; and after a gypsum model is dried completely, gravity casting is carried out, and for large thin-wall precise castings, great careful clearing, repairing and correcting are carried out after casting. According to the gypsum model precise casting technology, the crack risk of the castings can bereduced greatly, size precision is high, the casting cost is low, the casting quality is good, and defects of air holes, shrinkage holes, shrinkage depression, rising and the like are avoided.

The invention provides a precision casting method for column crystal guide vanes of a gas turbine. The precision casting method comprises the following steps: 1. a set of precision casting module is manufactured, and comprises a mold case and a chassis which are sequentially arranged from top to bottom; a wax pattern comprises a blade wax housing, an upper wax tread and a lower wax tread, two groups of vertically arranged seeding strips are embedded in the blade wax housing; the upper ends of one group of seeding strips correspond to inner arc shroud rings, and the lower ends of one group of seeding strips correspond to outer arc shroud rings; and the upper ends of the other group of seeding strips correspond to the outer arc shroud rings, and the lower ends of the other group of the seeding strips are flush with the bottom surface of the blade wax housing; 2. a group of seeding strips are embedded in the lower wax tread, and are vertically arranged around the section molded line of the vane bodies; 3. seeding sections are lined below tie bar bosses C and D; 4. materials are fused and poured into the precision casting module; and 5. the mold case of the precision casting module is withdrawn, so that the fuse is reversely sequentially solidified along the vane withdrawing direction, and a column crystal is formed. According to the column crystal guide vane bodies of the gas turbine manufactured by the invention, monoclinic crystals, crystal breakage and isometric crystal conditions are avoided, loosening and shrinkage cavity inside the vanes are avoided, the surface cracks are eliminated, and the column crystal guide vanes of the gas turbine are high in quality, high in efficiency and low in cost and can be applied to large-scale application and popularization.

The invention belongs to the fields of metal materials and metallurgy, aims to solve the problems that impurities of alloy are hard to separate, ingredients are nonuniform, the utilization rate of rare earth element is low, precipitated rare earth phases are nonuniform, the segregation is more, and effects for the quality is great by adopting the manner that alloying, rare earth process, and casting are conducted in a pot during a conventional manufacturing technology process, and provides a manufacturing technology for rare earth-magnesium alloy. According to the manufacturing technology, conducting adding, refining, and degassing with hexachloroethane degassing agent of alloy element in a melting pot; and pouring into a second pot after standing for 30 min, adding rare earth, and standing and casing. A manufactured bar material has uniform and stable metallographic structure and clear crystal boundary; the product is without pore, shrinkage cavity and cold shut, and the surface is smooth and without rugosity; the purity, ingredients, and equilibrium of physical properties of the product are guaranteed, the grain size of the alloy is refined, very stable dispersed phase is precipitated, and the rigidity and the decay resistance of texture are improved; therefore, product performances are allowed to be superior to an ordinary alloy standard.

The invention discloses a method for preparing a binary alternatively-doped BST membrane, belongs to the technical field of functional materials, and relates to a method for preparing a nanocrystalline BST membrane. The method adopts binary doping of Mn and Y, namely, carries out Mn or Y doping on an odd layer membrane and carries out Y or Mn doping on an even layer membrane; and the method adds a pre-crystallization processing step between cooling and crystallization steps. The membrane prepared by the method is smooth and compact with no crack or shrinkage cavity, and can greatly enhance the comprehensive dielectric tuning performance of the nanocrystalline BST membrane; and the obtained nanocrystalline BST membrane has a dielectric tuning rate of over 30.0 percent, a dielectric loss of less than 2.0 percent, a K factor of greater than 15.5, a high dielectric strength and a stable frequency characteristic and a temperature characteristic. The nanocrystalline BST membrane prepared by the method can be used for preparing a microwave tuning device (such as a phase shifter) instead of a ferrite and a semiconductor so as to remarkably reduce the manufacturing cost of the microwave tuning device; and furthermore, the nanocrystalline BST membrane prepared by the method is applicable for magnetic recording, pyroelectric focal plane arrays and the like.

The invention relates to a smelting degassing method of aluminum-silicon alloy liquid. Aiming at the actual condition that gas and impurities exist in the aluminum-silicon alloy liquid in the smelting course, a method of smelting direct-current electric field purification and circulation degassing outside a furnace is adopted to remove 99.5% of main gas, i.e. hydrogen, from the aluminum-silicon alloy liquid, so that an aluminum-silicon alloy having a compact metallographic structure can be obtained, and the aluminum-silicon alloy has no bubble or shrinkage cavity and is not subject to shrinkage porosity. The method has the advantages of advanced and reasonable process, continuous step, environment protection and energy conversation, the properties of aluminum-silicon products are greatly enhanced, the tensile strength can be enhanced by 91%, and the method is an ideal degassing method of aluminum-silicon alloy liquid.

The invention discloses thio salt modified epoxy resin and a preparation method and application of the thio salt modified epoxy resin. The thio salt modified epoxy resin is obtained by modifying epoxyresin by the thio salt; an emulsifier for a core-shell emulsion polymerization reaction is further prepared; and the emulsifier is further applied to an electrophoretic coating. The thio salt modified epoxy resin provided by the invention is used as an emulsifier for the core-shell emulsion polymerization reaction, and the thio salt modified epoxy resin emulsion is designed to participate in thefilm formation of the electrophoretic coating, is completely different from a general emulsifier in structure, does not act as a residual component, and does not have side effects.

The invention relates to conductive silver paste for fine line laser etching for a capacitive type touch screen. The conductive silver paste comprises the following components in parts by weight: 65-80 parts of metal silver powder, 5-10 parts of organic carrier, 3-23 parts of organic solvent, 0.1-1 parts of defoaming agent, 0.1-1 parts of leveling agent, 0.1-1 parts of anti-skinning agent, 0-1 parts of thixotropic agent and 0-1 parts of pigment; the preparation method for the conductive silver paste comprises the steps of mixing the organic carrier and the organic solvent to prepare a uniform colloidal solution; then adding the other components in sequence; and enabling the mixture to be mixed through a mixer, grinded through a three-roll mill, filtered, and the like to obtain the conductive silver paste for fine line laser etching for the capacitive type touch screen. Compared with the prior art, the conductive silver paste is simple in preparation process; the prepared conductive silver paste is low in resistance, high in adhesive force, high in surface hardness, corrosion resistance, and oxidization resistance, wherein the adhesive force between the conductive silver paste and a PET substrate can reach 5B level, and the surface hardness can reach greater than 3H; and therefore, the fine lines on the capacitive type touch screen can be manufactured by a laser etching process.

A waterborne wood toy coating is provided, which is produced by the styrene-acrylic emulsion, organic silicon (flatting agent, antifoamer), polyol ester, polyol ether, water, color sizing or filler pulp. The coating is friendly to the environment and does not contain heavy metal and other toxic substances, conforms to the requirements of the European toy test instruction EN-71parts and the toy safety standards of ASTMF963, which is a green environment protection coating having no harm to the health of the children. The viscidity of the watercolor primer is 100S plus or minus 30S, content of solid is not less than 41 per cent. The viscidity of the watercolor primer is 90S plus or minus 30S and the content of solid is not less than 30 per cent.

The invention relates to the field of valve body manufacturing, in particular to a valve body forging method. The valve body forging method saves materials and energy and reduces consumption on the condition of meeting the requirement of customers for product diversification. At first, blank forming is achieved by utilizing free forging for executing the following steps of A, selecting round steel with the weight being 1.15-1.25 times the weight of a finished valve body, riveting the two ends of the round steel, conducting indentation material separation, and forging the round steel into the preset size; B, enabling the two ends of the round steel to get off a table, forging eccentricity of the middle and the two ends, and forging the two ends into 260-degree octagons; C, then utilizing pressing blocks for making octagonal pressure grooves in the two ends into the preset size, and ensuring that flanges and grooves of a green body are within the design size range. Then, final forming is achieved by adopting semi-die forging for executing the following steps of a, forging the middle octagon of the green body in a vertical die buckling and pressing mode; b, after the middle octagon is formed, controlling the height of the flanges at the two ends through cushion blocks and forging the flanges to be rounded; c, finally, trimming the sizes of all parts of the forged piece into the designed sizes.

A micro-foaming injection structure comprises a quick injection nozzle, a mixer, a bulging device, a supercritical fluid generating device, a material tube group and an injection component. The micro-foaming injection structure is characterized in that the mixer, the bulging device and the quick injection nozzle are installed on the front end of the material tube group of a universal injection molding machine; when the injection molding machine performs or finishes a plastic smelting action, the bulging device is started, the supercritical fluid generating device injects supercritical fluid in the mixer and the material tube group, and then, the injection component propels a screw to inject, and meanwhile, the quick injection nozzle opens, the raw material and the gas are further mixed through the mixer and finally enter an injection mould to realize a minipore foaming function, the micro-foaming injection structure meets the technique demands of reducing the weight of the workpieces, shortening the forming period, reducing the mould locking force of the equipment, small internal stress and warpage, high flatness, non-shrinkage and stable dimension of minipore foaming, and furthermore, the structure is simple and effective, the cost is low and the practicability is strong.

The invention discloses a negative pressure hollow method to produce melt casting refractory, which includes steps mentioned below. The first step is to produce a mold according to the shape of a product. The second step is to use the negative pressure to absorb a thermoplastic film to the surface of the mold. The second third step is to put the mold with the thermoplastic film in a flask, which is equipped with a negative pressure generation device. When molding sands are berried, the flask is shaken to be evenly filled. Inner air is extracted out. The mold is fetched out of the flask. And ahollow cavity is obtained in the flask. The fourth step is to cast the melted refractory solution in the hollow cavity, which is made in the third step. The negative status is maintained until the melt solution is solidified. A finished product is obtained after cooling. With the method adopted, AZS refractory, alumina refractory or magnesia-alumina refractory products can be produced. When the products are molded, no discrete stomata is produced on the surfaces. The surfaces of the obtained melt molding products are bright light yellow. The material quality is compact and no shrinkage holes and cracks are made. The product quality is improved and the production cost is lowered.