170results about How to "Reduce porosity defects" patented technology

The invention discloses a resistance soldering method using a graphite electrode and a resistance soldering device. According to the resistance soldering method, the graphite electrode serves as a resistance soldering heating element which is used for soldering a hard alloy workpiece; the hard alloy soldered workpiece is placed in a closed steel soldering chamber; and when the graphite electrode is electrified and heated, carbon in the graphite electrode and oxygen surrounding the hard alloy soldering workpiece react chemically, so that oxygen in a local area at a soldering connection position is consumed. Oxygen-free porosity of a soldering connection brazing seam region between hard alloy and a steel substrate or between one piece of hard alloy and another piece of hard alloy can be realized, temperature fields of soldering connection portions are uniform, heating time is short, and efficiency is high. A graphite protecting device sleeves the graphite electrode and protects the graphite electrode from being damaged during resistance soldering pressurization. A pressure controller is arranged on the graphite electrode, pressure on the different soldering connection portions is not increased after the pressure of the graphite electrode reaches to a certain degree, and different demands of different soldering workpieces on external pressure are met.

A composite ceramic core that, in combination with a shell mold, is suitable for use in a casting process to produce metal alloy components. The core and casting process make use of a highly leachable interior layer in combination with an exterior layer that is less reactive than the interior layer in the presence of common alloying elements. The interior layer contains at least one hollow channel that allows a point of entry for a leaching solution, as well as exit for gaseous byproducts generated during the casting process.

The invention discloses an arc wire feeding additive oblique roller combined wheel hot rolling manufacturing method and device, and relates to the technical field of 3D printing. The wire feeding additive oblique roller combined wheel hot rolling manufacturing method and device are exquisite in structure, high in processing efficiency and good in processing effect, and can refine crystal grains ofan arc additive manufacturing formed part, improve compactness and reduce internal defects, thereby finally improving mechanical properties. The technical scheme of the invention is as follows: the manufacturing method comprises the following steps: (1) initialization; (2) arc wire feeding and material adding; (3) rolling; (3.1) strong shear deformation of an oblique roller; (3.2) primary flattening; (3.3) full flattening; (4) cooling; and (5) cutting of waste edges. The crystal grains of the arc wire feeding additive manufacturing formed part can be refined, the compactness is improved, internal defects are reduced, and the mechanical properties of the part are finally improved.

The invention discloses a manganese-contained free-cutting type silicon brass alloy. The alloy is composed of the following components, by weight percentage, 60.2-64.0wt% of Cu, 1.0-2.0wt% of Si, 0.2-1.0wt% of Al, 0.2-0.48wt% of Mn, 0.1-0.25 wt% of Pb, one or more of P, Mg and Sn, and the balance Zn and not greater than 0.5wt% of impurities, wherein the P accounts for 0.01-0.25wt%, the Mg accountsfor 0.01-0.25wt%, and the Sn accounts for 0.01-0.1wt%. The invention further discloses a preparation method for the alloy. The manganese-contained free-cutting type silicon brass alloy has the advantages of being excellent in dezincification corrosion resistance, good in casting property and cutting property, relatively low in cost and suitable for casting parts of a drinking water system, such as a faucet, a valve, a quick switch.

The invention provides a sector segment structure capable of compositely pressing the continuous casting solidification tail end of an extra-thick plate. An inner arc roller, an outer arc roller, an upper frame, a lower frame and side frames have enough strength and rigidity, four sensors and four oil cylinder assemblies are installed in the parts, the stretching or retraction strokes of the first oil cylinder assembly, the second oil cylinder assembly, the third oil cylinder assembly and the fourth oil cylinder assembly are controlled by detecting the first displacement sensor, the second displacement sensor, the third displacement sensor and the fourth displacement sensor, and then the opening degree between the inner arc roller and the outer arc roller of a sector segment is controlled, and the continuous casting solidification tail end of the extra-thick plate can be compositely pressed.

The invention discloses a preparation method for an environment-friendly casting material. The preparation method includes the steps of wax mold preparation, surface layer coating preparation, surface sand hanging, back layer coating preparation, back sand hanging, steam dewaxing, roasting and the like. According to the preparation method, fine wood bits and crop straw fibers serve as shell manufacturing materials, so that the using amount of refractory matter is reduced, and environmental protection is facilitated; reasonable matching is adopted, so that the breathability is increased on the premise that the shell strength is guaranteed; and cellular material attapulgite is adopted, so that exhausting is facilitated, the defect of casting air holes is reduced, the rate of finished products is increased, and meanwhile the weight of the mold shell is reduced.

The invention discloses a preparation method of an engine component. The preparation method comprises the steps of mold shell preparing, alloy burdening, melting and pouring, cooling, posttreatment and the like. A TiAl-based titanium aluminum compound is adopted as a component material, and therefore the engine component can continuously work for a long time at high temperature, performance is improved, and the service life is prolonged; wood bits and crop straw fibers are adopted as shell manufacturing materials, the usage amount of refractory matter is lowered, and environment friendliness is facilitated; a reasonable ratio is adopted, and air permeability is increased on the premise of guaranteeing the strength of a shell; a porous material, attapulgite, is adopted, air exhaust is facilitated, blowhole defects of the component are reduced, and the yield is increased; and meanwhile the weight of the mold shell is reduced.

The invention relates to a control method of a soft-reduction depressed region of a wide and thick plate continuous casting blank. The control method is implemented according to the following steps that (1) the non-uniform solidified tail end morphology is determined; (2) the soft-reduction depressed starting point and finishing point positions of the continuous casting blank in different width positions are determined; (3) the soft-reduction depression rate is regulated: the soft-reduction depression rate is set to be 0.8 to 2.2mm/m in a region Pend-Pend<1/2>; the soft-reduction depression rate is set to be 0.4 to 1.6 mm/m in a region Pend<1/2>-Pend. The control method provided by the invention is adopted for setting the soft-reduction depression rate, aiming at a determining method of the soft-reduction depressed region of a solidified blank case of the wide and thick plate continuous casting blank under the non-uniform growth condition, the implementation effect of a soft-reduction process is ensured, the segregation and loosening defects of a cross section center line of the wide and thick plate continuous casting blank can be effectively overcome, and good application prospects are realized.

The invention discloses a forming technology of an air cylinder cover casting. The forming technology of the air cylinder cover casting comprises the following steps of: firstly modeling the appearance profile and a sand core of the cylinder cover casting by adopting precoated sand; then assembling an outer model and the sand core and putting into a sand box; and then filling in dry sand or dry stones for pouring. According to the invention, the technology of combining precoated sand modeling and dry sand (stone) mold casting is adopted, the outer model moulding sand is molded and is assembled with the moulding sand, and is put into the sand box, the mold thickness adopts dry sand/stones to replace resin sand completely, and pouring is carried out after the dry sand/stones is/are compacted. Because the dry sand (stone) has no bonding agent and has good permeability, gases generated during pouring can be exhausted rapidly and smoothly; mold filling is stable; and because the metal liquids at the upper part are lower than metal liquids at the lower part, sequential condensation and dead head feeding are carried out smoothly; the mold-filling capacity is high; defects of cavity shrinkage, shrinkage porosity, incapability of pouring and the like can be prevented easily; and moreover, one-mold multi-element processing is easy to realize, and the production efficiency and casting technology yield are improved.

The invention provides an ultra-low speed aluminum alloy die-casting system. The system comprises an aluminum alloy die casting machine and a heat preserving furnace, wherein the heat preserving furnace is provided with a quantitative pouring pump, wherein the quantitative pouring pump is connected with a liquid conveying pipeline; the outlet end of the liquid conveying pipeline is provided with a liquid conveying groove connected to a funnel on a die-casting chamber channel; a refractory mortar layer is laid on the surface of the liquid conveying groove; a release coating layer is sprayed on the surface of the refractory mortar layer; a release coating layer is uniformly coated on the surface of the funnel; the thickness of the release coating layer is between 3 and 5 millimeters; and an included angle between the liquid conveying groove and an ejection horizontal plane is between 15 and 25 degrees. The invention also provides an alloy melt temperature control range and an operation specification for the heat preserving furnace of the system. Through system setting, molten metal flows through a chute and the funnel before casting; and due to the adoption of small-angle ultra-low speed die casting and shaping, the molten metal flows stably without eddy current or splashing, gas inclusion in a shaping process is decreased, the surface of a casting molded by die casting is flat and smooth, crystal particles are fine and air holes inside a product have a small number of defects.

The invention discloses a water glass sand hardener which is composed of the following components in percentage by weight: 20-80% of organic ester, 6-24% of phosphoric acid with the mass concentration of 80%, 2-8% of soluble acid phosphate, 1-4% of urea and 11-44% of water. The preparation method is as follows: mixing and dissolving the soluble acid phosphate and the urea into the water to form a solution; and evenly mixing with the phosphoric acid and the organic ester to obtain the water glass sand hardener. The water glass sand hardener of the invention has the advantages of convenient use, good hardening effect, low cost and controllable hardening speed, can obviously lower the water glass addition and obviously improves the moulding sand collapsibility.

The invention discloses a method and device for quantitatively measuring the content of gas inside an aluminum alloy die casting. The method comprises the steps of: washing and measuring certain part or the whole of the die casting, and then placing in a vacuum chamber, vacuumizing to below 0.01Pa by using a vacuum pump, and recording a vacuum pressure value F1; isolating the vacuum chamber from the vacuum pump, heating the die casting to ensure that the die casting is melted and gas in the die casting escapes and the pressure in the vacuum chamber is increased, and recording a vacuum pressure value F2; and finally, converting using F2-F1 according to a corresponding gas standard curve to obtain the content of the gas inside the die casting. The device comprises a heating furnace, a vacuum system, a quantitative gas supplying system and a cooling system. The method allows to quantitatively measure the content of the gas inside the die casting, is high in measuring precision and is capable of accurately evaluating the defect of pores in the die casting. The invention provides a scientific basis for evaluating the defect of the pores in the die casting and optimizing a casting process.

The invention discloses a silicon carbide ceramic connection method and a silicon carbide cladding, and the silicon carbide ceramic connection method comprises the following steps: S1, taking liquid polycarbosilane as a precursor, and adding a curing agent for curing treatment; S2, enabling the cured polycarbosilane to be subjected to heating pretreatment, and forming precursor powder; S3, mixing the precursor powder and an organic solvent to prepare slurry; S4, smearing the slurry between a SiC cladding tube and an end plug which are matched with each other, and forming a sandwich connection structure; and S5, performing high-temperature curing and cracking treatment on the sandwich connection structure, so that the slurry forms a connection layer which is tightly connected between the SiC cladding tube and the end plug. According to the silicon carbide ceramic connection method, high-strength connection of the SiC cladding and the end plug at a low temperature (less than or equal to 1500 DEG C) and without pressure is realized, filler does not need to be added, the pore defect of a middle connection layer is reduced, and the air tightness of a formed joint is improved; and the connection process is simple and has low requirements on equipment, and the cost is reduced.

The invention discloses a composite alterant of a cast aluminum alloy for iron-enriched phase alteration and an alteration method thereof, and relates to the field of composite alteration of the castaluminum alloy. The composite alterant comprises an Mn agent, an Al-RE intermediate alloy and an Al-Sr intermediate alloy, wherein the Mn agent is an Al-Mn intermediate alloy or a Mn additive; the adding ratio of the Mn agent is 30-90% of the Fe content in the cast aluminum alloy; the RE adding amount of the Al-RE intermediate alloy is 0.05-0.2% of the melt mass of the cast aluminum alloy; and theSr adding amount of the Al-Sr intermediate alloy is 0.02-0.05% of the melt mass. The composite alterant is specifically suitable for a high-strength and high-toughness cast aluminum silicon alloy with low Fe content and a die-cast aluminum silicon alloy with high iron content, and can achieve synchronous refining of three structures of alpha-Al, eutectic silicon and an iron-enriched phase to improve the alloy ductility.

The invention relates to a SiCf/SiC composite material and a preparation method thereof. The preparation method comprises the following steps: (1) mixing carbon black and silicon carbide micro powderwhich are used as solid phases with water, adding an adjuvant agent, performing ball grinding for mixing, mechanically stirring the mixture in vacuum, and debubbling the mixture to obtain dipping slurry; (2) dipping silicon carbide fiber cloth in the dipping slurry for vacuum-pressure dipping to obtain a fiber cloth dipped material, starching the fiber cloth dipped material for thicknessing, adhering and stacking the material, burying the material with water-absorbent resin, placing the material into a mold for cold isostatic pressing, and drying and thermally treating the mold to obtain a carbon-containing preform, wherein a silicon carbide fiber contains a boron nitride interface; (3) performing reactive melt infiltration on the carbon-containing preform, thus obtaining the SiCf/SiC composite material. The preparation method can be simplified, the production energy consumption can be reduced, and the production efficiency can be improved; pore defects in the carbon-containing preformcan be substantially reduced, so that the compactness of the SiCf/SiC composite material is increased, and the content of residual silicon is reduced at the same time.