18results about How to "Reduce porosity defects" patented technology

The invention discloses a large-size large-curvature TiAl alloy turbine blade high-precision numerical control machining method which comprises the following steps that TiAl alloy is poured into a metal mold, and a blade ingot is manufactured; the blade ingot is subjected to hot isostatic pressing and heat treatment; firstly, a blade profile and runner surfaces of upper and lower margin plates are machined according to a blade model, the upper margin plate, sealing teeth and the lower margin plate of the blade are continuously machined, and a root extending part is machined to a tolerance zone on a three-dimensional model to serve as a reference surface; a three-coordinate measuring machine is adopted to carry out blade profile and full-size measurement on a machined blade, and the size is manually assisted to be ground to a blade product tolerance zone. According to the method, the advantages of five-axis machine tool machining are utilized, the problems that the metallurgical quality of the large-size blade is difficult to control and manual grinding is difficult to control are solved, the consistency of products machined through the method is good, the quality is guaranteed, the efficiency and the percent of pass can be greatly improved, and the productivity is greatly improved.

According to the scheme, the brake disc casting device comprises an upper sand mold and a lower sand mold located below the upper sand mold, the upper sand mold and the lower sand mold are vertically combined to form an annular mold cavity, a vertically-through first flow channel is formed in the upper sand mold, a second flow channel is formed in the lower sand mold, one side of the second flow channel is communicated with the first flow channel to form a pouring gate, and the other side of the second flow channel is communicated with the pouring gate. The other side of the second runner is communicated with the cavity so that molten metal can flow into the cavity through the pouring gate, the upper sand mold is provided with at least one overflow groove with a downward opening, and the overflow groove is communicated with the top of the cavity; the shielding structure is arranged on the lower sand mold and located in the mold cavity, the shielding structure shields part of the opening of the overflow groove, the overflow groove is formed in the top of the mold cavity, bubbles and waste residues in molten metal can be naturally accumulated in the overflow groove, the bubbles and the waste residues in the mold cavity are reduced, and the production efficiency is improved. And therefore, the pore defect problem of the upper disc surface of the formed casting is reduced, and the process yield is improved.

The invention discloses a method for improving the structure and performance of a 6063 aluminum alloy formed through selective laser melting, and belongs to the technical field of selective laser melting. Titanium powder and zirconium hydride in a certain proportion are selected as doping agents, the doping agents are evenly mixed with 6063 aluminum alloy powder through a ball milling method, and then drying and dehumidification are conducted; and the mixed alloy powder is put into selected-area laser melting equipment, manufacturing is carried out on the surface of a base material under inert gas protection, and the 6063 aluminum alloy is obtained after laser, scanning, powder laying and deposition. According to the method, the microstructure and the mechanical property of the selective laser melting forming 6063 aluminum alloy are obviously improved, so that the selective laser melting forming 6063 aluminum alloy meets the industrial performance requirement of SLM, and good market competitiveness is achieved.

The present application relates to the technical field of surface strengthening in water conservancy and power industry, and particularly relates to a kind of water turbine surface coating on-line fast maintenance of cavitation erosion resistant wire and on-line fast maintenance method based on it.The present application is specially made of nickel-chromium band coated high-tungsten flux-cored wire, and the main components of the wire are W, Cr, Si, B, Mn, Nb and the balance of Ni, which can be adapted to handheld laser welding machine operation.The supporting maintenance method is carried out in sequence, including failure layer polishing and shaping, cleaning and impurity removal, 150-250 DEG C preheating pretreatment, then using handheld laser welding machine with the wire, through limiting laser power, welding speed, wire feeding speed and overlap amount parameters, layer-by-layer cladding repair, finally through heat preservation and slow cooling, surface polishing and shaping to complete the maintenance.The present application can realize on-line in-situ fast repair of water turbine component cavitation erosion damage, and the cladding layer has dense structure, high bonding strength, excellent cavitation erosion and wear resistance, effectively solves the problem of low repair efficiency and on-site maintenance in prior art, and is suitable for on-site maintenance of hydroelectric equipment.

The invention relates to the technical field of castable, in particular to high-performance tundish cover castable based on high-aluminum ceramic chip recycled aggregate and a preparation method of the high-performance tundish cover castable. The castable comprises high-aluminum ceramic chip recycled aggregate, modified hollow alumina microspheres, andalusite and other components, and through roasting stabilization treatment of the recycled aggregate and multi-layer coating modification of the microspheres, the problems of poor heat preservation property and concentrated thermal stress caused by high doping amount of the recycled aggregate are solved. The andalusite cooperates with the modified microbeads to optimize aggregate-andalusite-microbead three-phase interface combination by virtue of the low-expansion characteristic and the active surface, so that the thermal shock resistance and the structural compactness are enhanced. The product has excellent heat preservation and heat insulation performance, high strength and slag corrosion resistance, resource efficient utilization of waste high-aluminum ceramic chips is achieved, and the service life of the tundish cover is prolonged.

The invention discloses a copper-tungsten alloy-copper-steel composite electrical contact and a preparation method thereof, and relates to the technical field of alloy material preparation. Comprising the following steps: performing compression molding on tungsten powder to obtain a blank block; pre-sintering the briquette to prepare a framework, so as to obtain a tungsten framework; the theoretical copper infiltration weight is calculated according to the weight of the tungsten framework, copper infiltration is conducted on the tungsten framework according to 1.2-1.4 times of the theoretical copper infiltration weight, and the copper-tungsten alloy is obtained; the method comprises the following steps: respectively machining and cleaning a copper-tungsten alloy, a steel part and a copper part, then assembling, placing a chromium-copper alloy on the top of the assembled copper part, vacuumizing, sintering at 1250-1300 DEG C, and cooling to obtain a blank; and carrying out heat treatment on the blank to obtain the copper-tungsten alloy-copper-steel composite electrical contact. According to the method, the copper-tungsten alloy, the copper and the steel are combined, the bonding strength between matrixes is improved, the consistency and the stability of the quality of a welded product are guaranteed, and the air hole defect of a bonding surface is reduced.

The present invention belongs to the technical field of material preparation, and aims to solve the problem that the preparation process of the existing metal ceramic material is difficult to accurately control the distribution and grain size of each phase in the metal ceramic matrix, resulting in uneven microstructure of the material, thereby affecting the comprehensive performance of the material. To this end, the present invention provides a method for preparing a fiber-reinforced metal ceramic material, comprising: pre-treating silicon carbide fiber; mixing and grinding titanium metal powder and silicon carbide ceramic powder according to a predetermined ratio; then adding silicon carbide fiber particles and placing them in an ultrasonic mixer; adding a dispersant and a binder and mixing them again; the mixture is sequentially cold isostatically pressed and hot pressed; the obtained blank is sequentially pre-sintered, high-temperature sintered, cut and surface treated. The metal ceramic material prepared by the present invention is significantly improved in strength, toughness, hardness, high temperature resistance, wear resistance and corrosion resistance, can better meet the high performance requirements in the aviation field, and provide strong support for the aviation industry.

This invention relates to the field of welding materials technology, and particularly to a high-performance aluminum-lithium alloy flux-cored welding wire and its preparation method. The high-performance aluminum-lithium alloy flux-cored welding wire comprises: an aluminum-based metal strip outer sheath; and flux powder filled within the outer sheath. The flux powder includes deoxidizing components, alloy components, arc-stabilizing components, slag-forming components, and binding components. The alloy components of the aluminum-lithium alloy flux-cored welding wire, by mass percentage, include: Cu: 3.7%-4.3%, Li: 0.8%-1.5%, Mg: 0.25%-1%, Zr: 0.1%-0.16%, with the balance being Al and unavoidable impurities. The burn-off rate of active elements is significantly reduced, and the composition control accuracy reaches ±0.05%. The flux structure encapsulates highly active elements such as Li, Mg, and Zr in powder form within the aluminum-based outer sheath, avoiding high-temperature volatilization and oxidation in traditional smelting processes. These elements are released only during welding, achieving precise composition control and enabling the stable preparation of aluminum-lithium alloy welding wires with high Li content (2%-3%).

The invention discloses an aluminum alloy refining agent for battery foil and a preparation method of the aluminum alloy refining agent, and relates to the technical field of alloy preparation, and the preparation method comprises the following steps: preparing nanoscale aluminum alloy powder by using a sol-gel method, compounding a nano aluminum alloy with a salt solution by using a solution mixing method, and filtering and drying the obtained suspension to obtain an aluminum alloy nano refining agent. The method has the advantages that nano aluminum oxide is prepared through a sol-gel method, the aluminum alloy easily absorbs gas such as hydrogen in the smelting process, the aluminum alloy nano refining agent can effectively remove hydrogen in molten aluminum, the pore defect in a casting can be greatly reduced, the density and the mechanical property of the aluminum alloy casting can be improved, and the casting quality is improved. In the manufacturing process of some aluminum alloy parts with the high requirement for air tightness, after the nanometer refining agent is used, the porosity of the product is obviously reduced, the requirement for high-end application is met, other gas dissolved in molten aluminum can be removed through the nanometer refining agent, and the molten aluminum is made to be purer.

This application relates to a mold and casting process for casting end caps of shell-type hydraulic valve bodies, belonging to the technical field of casting processing. The mold includes a mold body with a cavity formed within it. A runner sand core is disposed within the cavity and fixedly connected to the mold body. A gating port is provided at the bottom of the mold body and communicates with the cavity. The bottom gating assembly includes a sprue base plate and a vertical gating pipe. A horizontal runner is provided within the sprue base plate, with its length direction along the horizontal direction. The vertical gating pipe is vertically positioned above the sprue base plate, with its lower end connected to the sprue base plate and communicating with the horizontal runner. The mold body is fixed to the sprue base plate, and the gating port communicates with the horizontal runner. This application reduces the occurrence of splashing, turbulence, and air entrapment of molten metal within the cavity, thereby reducing the generation of secondary oxidation inclusions and porosity defects inside the casting, which improves the final casting quality.

The invention relates to the technical field of alloy coating materials, and particularly discloses an anti-oxidation coating for a high-pressure hot-pressing mold and a preparation method of the anti-oxidation coating. The high-pressure hot-pressing mold anti-oxidation coating comprises a transition layer and a functional layer which are sequentially arranged from a mold base body to the outside, the transition layer is a TiN-SiC gradient composite layer, the functional layer takes Al2O3-NiCrAlY as a base body, and nano ZrB2 and rare earth CeO2 which are subjected to double modification treatment are compositely doped; and the dual-modified nano ZrB2 is ZrB2 particles which are coated with a silane coupling agent KH-560 and a NiCr alloy. The anti-oxidation coating of the high-pressure hot-pressing mold has both oxidation resistance and wear resistance, and the high-temperature hardness stability and wear resistance of the anti-oxidation coating are effectively enhanced.

The invention relates to the technical field of die casting equipment, in particular to lamp shell die casting equipment capable of eliminating air holes, which comprises a base, a bracket is fixedly mounted on the surface of the base, three groups of linearly distributed cylinders are mounted at the top of the bracket, and a material injection head, a movable die and a fixed plate are fixedly mounted at the output ends of the cylinders respectively; a suction cup is fixedly installed on the bottom face of the fixing plate. According to the die-casting die, through cooperation of the sliding blocks and the sliding rails, the stability of the fixed die structure is further enhanced, air retention in a die cavity or gas mixing into a die-casting piece caused by die shaking is prevented, in the die-casting process, the pump body on the movable die side communicates with the exhaust groove in the fixed die through the connecting pipe, redundant gas in the die can be exhausted in time, and the die-casting quality is improved. Not only can gas in the die cavity be quickly exhausted, but also the sealing performance and the density of a finished product are greatly improved, so that the problem of air hole defects on the surface and inside of the product is obviously reduced.

The utility model relates to a composite material repair paving layer curing device which is characterized in that a repair paving layer is adhered to an area to be repaired, and the hot end of a thermocouple is transversely adhered to the edge of the repair paving layer in a sealing manner through a high-temperature adhesive tape; the stripping layer covers the repair paving layer and the thermocouple; the porous isolating membrane covers the stripping layer; the glass fiber cloth covers a porous isolating membrane; the non-porous isolating membrane covers the glass fiber cloth; the pressure equalizing plate is covered with a non-porous isolating membrane; the electric blanket covers the pressure equalizing plate; the breathing material covers the electric blanket; the vacuum base is diagonally placed on the breathing material; the vacuum film is bonded with a to-be-repaired part through a double-sided sealing adhesive tape to form a vacuum sealing bag and is connected with the vacuum base through a vacuum suction nozzle, and the vacuum suction nozzle is connected with an external vacuum pump. Compared with the prior art, the device has the advantages of high fitting degree of a repaired surface, high flatness, high reliability and the like.

The invention relates to an amorphous SiBCN ceramic block with high density and excellent oxidation resistance and a preparation method of the amorphous SiBCN ceramic block, and belongs to the technical field of high-performance ceramic materials.The preparation method of the amorphous SiBCN ceramic block comprises the steps that after polyborosilazane is cured, smashing, ball milling and vacuum pyrolysis are conducted, and amorphous SiBCN ceramic powder is obtained; and carrying out spark plasma sintering on the amorphous SiBCN ceramic powder to obtain the amorphous SiBCN ceramic block. The preparation method of the amorphous SiBCN ceramic block provided by the invention can be used for preparing the amorphous SiBCN ceramic block with high density, low pore defect, adjustable size, small shrinkage rate and excellent oxidation resistance, and can effectively solve the problems of limited material size, more pores and the like in the traditional preparation process of the SiBCN ceramic block.

The application relates to the technical field of alloy coating materials, and particularly discloses a high-pressure hot-pressing die oxidation-resistant coating and a preparation method thereof. The high-pressure hot-pressing die oxidation-resistant coating comprises a transition layer and a functional layer arranged outward from a die base body, the transition layer is a TiN-SiC gradient composite layer, the functional layer takes Al2O3-NiCrAlY as a base body, and is compounded and doped with double-modified nano ZrB2 and rare earth CeO2; the double-modified nano ZrB2 is ZrB2 particles coated with a silane coupling agent KH-560 and a NiCr alloy. The high-pressure hot-pressing die oxidation-resistant coating has oxidation resistance and wear resistance, and effectively enhances the high-temperature hardness stability and wear resistance of the oxidation-resistant coating.

The present invention provides a MIG welding method for high-pressure aluminum die castings and profiles, and relates to the field of welding technology. The present invention adopts a direct current pulse current for welding in the arc starting stage, and adopts a relatively high welding current, so as to increase the heat input in the arc starting stage, and ensure that the molten pool can be formed quickly; after the arc starting is completed, on the basis of reducing the welding current, the direct current pulse current is gradually switched to a variable polarity pulse current, and the time proportion of the negative polarity stage in the welding current waveform is gradually increased, which is conducive to improving the melting speed of the welding wire during the welding process, thereby increasing the amount of welding wire filling in the weld bead, and at the same time, it is conducive to reducing the heat accumulation during the welding process, and can effectively inhibit the generation of pores in the molten pool, so as to reduce the pore defects in the welding sample. In addition, the welding current is gradually reduced before the arc closing stage, and the arc closing is carried out by using a variable polarity short circuit, which is conducive to ensuring that the arc pit is full during welding, and is also conducive to reducing the pore defects in the welding sample.

This utility model discloses a cooling bed with an auxiliary function to reduce porosity in microchannel aluminum flat tubes, relating to the field of microchannel aluminum flat tube production technology. It includes a frame and support legs. The top of the support legs is fixedly connected to the frame, and a conveying roller is rotatably connected to the inner side of the frame. A cleaning mechanism is provided on the side of the conveying roller, and a fixing plate is fixedly connected to one end of the frame. When the conveying roller rotates and conveys the aluminum flat tube, the system drives a reciprocating screw via a motor, causing the cleaning plate and brush on the slider to reciprocate. This design causes relative motion between the brush and the rotating surface of the conveying roller, effectively removing alumina particles adhering to the roller surface. This continuous cleaning mechanism ensures that the surface of the conveying roller always maintains good contact with the bottom of the aluminum flat tube, guaranteeing the uniformity of the cooling process. Uniform cooling facilitates the timely discharge of gas from the bottom of the aluminum flat tube, thereby significantly reducing porosity defects at the bottom of the aluminum flat tube.

A laser welding method, milling single edge groove on two workpieces to be welded respectively; assembling and aligning the two workpieces to be welded after cleaning; using laser swing filler wire welding method in heat conduction welding mode to carry out non-penetration welding, only using filler wire metal to fill the upper groove of the test plate, obtaining the first filler wire welding seam with obvious excess height; using laser self-melting welding method in keyhole welding mode to carry out full penetration welding, laser beam penetrating the first filler wire welding seam and the whole workpiece thickness at the same time, obtaining the second full penetration welding seam. In the process of the second full penetration welding, the upper first filling metal part is partially melted and moves to the lower part under the action of the melt pool convection, and under the action of surface tension, the upper surface of the final weld has only slightly reduced excess height, and the lower surface forms obvious excess height.