76results about How to "Improve brazing performance" patented technology

The invention provides a penetration brazing preparation method of a high-content wolfram carbide gradient wear-resisting coating, comprising the following steps: sequentially sticking a plurality of layers metal wire net flexible compound cloth containing wolfram carbide WC or wolfram carbide-cobalt WC-Co and nickel-chromium alloy powder Ni-Cr on a metal base body by using an epoxy resin binding agent; and carrying out penetration brazing in a vacuum furnace. Compared with the prior art, the Rockwell hardness of a researched coating with the WC content of 70% is HRC64-70 and the wear resistance is obviously improved.

The invention provides a soldering flux for brazing a diamond cement carbide. The soldering flux comprises the following components in percentage by weight: 12 to 33% of Na2B4O7, one or two of 5 to 14.8% of KBF4 and 2 to 12% of MF, wherein M is alkali metal, one or two of 0.5 to 10% of CoWO4 and 1 to 15% of CoCl2, one or two of 0.5 to 9% of an oxide of Mo, 0.5 to 5% of the oxide of Ni and 0.5 to 10% of the oxide of W, and the balance of H3BO3. The soldering flux for brazing the diamond cement carbide has a wide scope of application, and can be applied to brazing a cemented carbide such as Co, Mo and Ni and a diamond. Compared with conventional soldering flux, the soldering flux disclosed by the invention can increase an expanding area; a weld joint has a better appearance and high shearing strength, so that a brazing performance is improved.

A hollow aluminum structure that will be brazed includes at least one brazing sheet having a filler metal layer clad onto a core layer. The core layer is composed of aluminum or an aluminum alloy containing less than 0.2 mass % Mg. The filler metal layer is composed of an aluminum alloy that contains Si: 4.0-13.0 mass % and Bi: 0.01-0.3 mass %, and further contains Li: 0.004-0.08 mass % and/or Be: 0.006-0.12 mass %, the filler metal layer containing less than 0.1 mass % Mg. The hollow aluminum structure is assembled such that the filler metal layer is present at locations that will form both an interior-facing brazed joint and an exterior-facing brazed joint. Then, flux is applied onto the filler metal layer at the location that will form the exterior brazed joint, and the hollow aluminum structure heated in an inert gas atmosphere to form the interior brazed joint and the exterior brazed joint.

This brazing sheet has a core material and a brazing material clad on one or both sides of the core material, and is used for brazing in an inert gas atmosphere without using a flux. The core material contains 0.35-0.8% (mass%, same hereafter) of Mg, wherein the balance has a chemical composition comprising Al and inevitable impurities. The brazing material contains 6-13% of Si and 0.001-0.05% of Bi, and restricts Mg to less than 0.05%, wherein the balance has a chemical composition comprising Al and inevitable impurities.

The invention relates to a wire mesh flexible composite fabric for surface modification and a preparation method of the wire mesh flexible composite fabric. The wire mesh flexible composite fabric comprises wolfram carbide (WC) or WC-cobalt (Co), mechanically alloyed nickel-chromium alloy powder, a forming agent and a binding agent. The wire mesh flexible composite fabric for surface modification is made through roll forming. By adopting a mechanical alloying technology, a nanocrystalline technology and a wire mesh technology, the preparation forming property of the flexible fabric is greatly improved, the thickness of the flexible fabric is extremely controlled, and the design idea of gradient coatings of more than two layers can be realized, so that the stress is reduced and the welding texture and the welding property are improved. The WC coating with excellent performance is prepared.

The invention relates to novel insoluble non-corrosive aluminum soldering flux and a preparation method thereof, belongs to insoluble non-corrosive aluminum soldering flux and preparation technology thereof, and in particular to insoluble non-corrosive aluminum soldering flux containing a potassium composition, an aluminum composition, a cesium composition, a silicon composition and a fluorine composition and preparation thereof. The insoluble non-corrosive aluminum soldering flux solves the problems of poor wettability of solder, increase of the welding difficulty and influence of the braze welding quality during braze welding because aluminum is active and compact and stable oxide is easy to form on the surface of the solder. The preparation method adopts a technical proposal that the preparation method comprises the following steps: firstly, making the aluminum composition react with hydrofluoric acid, and adding the potassium composition and the cesium composition in turn; secondly, adding hydrofluosilicic acid into the mixture for reaction after the reaction is over; and thirdly, performing dehydration, drying, crushing and sieving through 20 mu m sieve, and preparing the insoluble non-corrosive aluminum soldering flux. The insoluble non-corrosive aluminum soldering flux has the advantages of convenient use, protection of brazing metals and the solder from being continuously oxidized during heating, improvement of the wettability of the solder on the surfaces of substrate metals, promotion of flowing of the solder, filling of joint gaps, formation of braze welding seams with clean and compact surfaces, and the like, and can be widely applied to braze welding of aluminum workpieces and aluminum alloy workpieces.

This invention relates to a method of manufacturing an aluminum heat exchanger tube. In forming a thermally sprayed layer 21 on a surface of an aluminum flat tube by thermally spraying Al-Si alloy thermal-spraying particles, quenching the thermally sprayed thermal-spraying particles in a molten state to make them adhere to the tube core 2a. The surface of the thermally sprayed layer 21 is smoothed with, e.g., reduction rolls to form a brazing layer 20. With this method, brazing defects due to fin detachment, erosion to the tube of the brazing material, etc., can be prevented, resulting in good brazing performance.

A cylindrical member of a tube for a heat exchanger is made of a pair of flat plate portions, and a pair of curved portions for connecting the pair of flat plate portions to each other. One of the pair of curved portions constructs a bonded portion in which an outer wall portion and an inner wall portion are bonded to each by brazing in a state where the outer wall portion and the inner wall portion overlap each other. The inner wall portion has a portion opposite to the outer wall portion put into close contact with the outer wall portion and is bonded to the one flat plate portion in a state where a tip end portion of the inner wall portion opposite to the one flat plate portion is separated from the one flat plate portion.

A method for manufacturing a heat exchanger (1) includes joining an inner fin (3) to a hollow structure (20) formed from at least two clad plates (200a, 200b) by heating and brazing a filler metal layer (B). Each clad plate has a core layer (A) composed of an aluminum alloy that contains Mg: 0.40-1.0 mass %. The filler metal layer is composed of an aluminum alloy that contains Si: 4.0-13.0 mass %, and further contains Li: 0.0040-0.10 mass %, Be: 0.0040-0.10 mass %, and/or Bi: 0.01-0.30 mass %. The inner fin is composed of an aluminum alloy that contains Si: 0.30-0.70 mass % and Mg: 0.35-0.80 mass %. A flux (F) that contains cesium (Cs) is applied along a contact part (201), and the vicinity thereof, of the at least two clad plates prior to the heating. A heat exchanger (1) may be manufactured according to this method.

The invention relates to the field of gold plating technologies, in particular to an aluminum material surface local gold plating process. The process comprises the following steps of removing impurities on the surface of an aluminum material; immersing the aluminum material treated in the step A into a zinc dipping solution, reacting until a zinc coating is formed on the surface of the aluminum material, and performing washing with water; immersing the aluminum material subjected to zinc immersion in the step B into a nickel plating solution, reacting until a nickel plating layer is formed onthe surface of the aluminum material, and performing washing with water; immersing the aluminum material subjected to nickel plating in the step C into a gold plating solution, reacting until a goldplating layer is formed on the surface of the aluminum material, performing washing with water, and performing drying; dividing the surface of the aluminum material plated with gold in the step D intoa gold plating area and a non-gold plating area, and wrapping the surface of the gold plating area with a layer of shielding material; and immersing the aluminum material subjected to local shieldinginto a gold stripping mixed solution, reacting until the gold plating layer of the non-gold-plating area of the aluminum material disappears, performing washing with water after the nickel plating layer is completely exposed, and performing drying to obtain a local gold-plating plated part. The process has the effect of improving the binding force between the plating layer and the plated part.

There is provided a Ni—Cr—Fe-based alloy brazing filler material to which Cu is added, and which has a low melting temperature, and is inexpensive and excellent in corrosion resistance and in strength, for use in manufacture of stainless-steel heat exchangers or the like, specifically, a Ni—Cr—Fe-based alloy brazing filler material, including, in mass %, Cr: 15 to 30%; Fe: 15 to 30%; Cu: 2.1 to 7.5%; P: 3 to 12%; and Si: 0 to 8%; and the balance being Ni and unavoidable impurities, wherein the total content of Cr and Fe is 30 to 54%, and the total content of P and Si is 7 to 14%.

The invention discloses a silver-based brazing filler metal alloy. The silver-based brazing filler metal alloy comprises the following components of, in percentage by mass, 26%-28% of Cu; 3.5%-5.5% ofGa; at least two of the following elements of 0.001%-0.5% of Ni; 0.001%-0.5% of Co; 0.001%-0.5% of Fe; at least one of the following elements of 0.001%-0.5% of Au; 0.001%-0.5% of Pt; 0.001%-0.5% of Pd; at least one of the following elements of 0.001%-0.5% of In; 0.001%-0.5% of Sn; at least one of the following elements of La, Ce, Pr, Nd, Sm, Eu, Er, Yb, Y and Sc; and the balance Ag. The inventionfurther provides a preparation method of the silver-based brazing filler metal alloy and preparation methods of a foil strip and a wire. When the silver-based brazing filler metal alloy is used for welding a vacuum electronic device, a nickel plating process is omitted, and environmental pollution is prevented; meanwhile, the problems of high welding temperature and inconsistent melt flow pointsof Ag-28Cu-xNi alloy are solved; and the brazing filler metal alloy is good in brazing manufacturability and good in wettability, the brazing rate of kovar alloy, stainless steel and the like is higher than 95%, and the shear strength sigma b of a brazed joint is larger than or equal to 285 MPa.

The invention relates to an aluminum alloy radiating fin for a heat exchanger. The aluminum alloy radiating fin comprises the composition by the weight percentage: 0.3-0.5% of silicon, 1.8-2.0% of manganese, 0.05-0.08% of nickel, 0.3-0.5% of copper, 0.01-0.03% of magnesium, 0.1-0.3% of iron, 1.5-2.0% of zinc, 0.001-0.0015% of yttrium, 0.01-0.03% of titanium, 0.0001-0.00015% of boron, and the balance being aluminum and inevitable impurities. Wall thinning and weight lightening of the aluminum alloy radiating fin for the heat exchanger become possible, and in addition, the reliability of a heat radiating fin material and the heat exchanger is improved.

The invention discloses an aluminum alloy brazing filler metal constituted by Si in a range from 4.0 to 13.0wt%, Sr 0.001 to 0.050wt%, P 0.0001 to 0.0090 wt%, and other aluminum alloy formed by A1 and other inevitable foreign matters and a brazing plate using the same. The aluminum alloy brazing filler metal has advantages of excellent, strength, hard-solder performance, and anti-corrosion performance.

The invention relates to a brazing auxiliary device and a brazing device for a cutting bit. The brazing auxiliary device comprises a pressure bar device for discharging gas to a brazing part; the pressure bar device is provided with a plurality of vibrating devices. The embodiment of the invention is mainly used for achieving a certain auxiliary effect on discharge of gas in a solder after completion of brazing; the pressure bar device which is in contact with the solder after brazing is arranged and a plurality of vibrating devices are arranged on the pressure bar device, so that the pressure bar device can be driven to generate a plurality of vibrations in different directions through the vibrating devices, the end part of the pressure bar device is in contact with the solder, the vibrations in a plurality of directions are transferred to the solder to quicken the discharge of the gas in the solder, improve the brazing effect and save the brazing time.