868 results about "Diffusion welding" patented technology

The invention discloses a diffusion welding method of titanium or titanium alloy and stainless steel. A plate pack having the same material quality with welded workpieces is welded into a block structure in advance. The plate pack is lengthways cut into slices along the block structure to form a structural middle layer 7. The middle layer is processed and then vertically arranged between the welded workpieces for diffusion welding. Because the middle layer having the same material quality with the workpiece is adopted, a joint heterogeneous interface combination mode is changed into a combination mode that half heterogeneous workpieces are directly combined and half heterogeneous workpieces are combined, and the titanium or titanium alloy and stainless steel workpieces are in high-intensity connection. In the diffusion welding method, the tensile strength of the joint is improved to above 80% from 50-70%(week side workpiece intensity) obtained by the direct diffusion welding technology, and various types of titanium or titanium alloy and stainless steel can be in high-intensity connection.

A welding method of aluminum blank and aluminum alloy backboard comprises the following steps: providing an aluminum target blank and an aluminum alloy backboard; placing the aluminum target blank and the aluminum alloy backboard into a vacuum sheath and transferring into a welding device; adopting a hot isostatic pressing technique for diffusion welding, welding the aluminum target material blank to the aluminum alloy backboard for forming a target material assembly; and after the welding, executing air cooling and detaching the vacuum sheath and taking the target material assembly out. The invention adopts the vacuum sheath for realizing the isolation of target material from the backboard and the air. The oxidization on the surface of the metal in welding is effectively prevented and the cost of vacuum device is reduced. On the other hand, the hot isostatic pressing technique is used for the diffusion welding. The bonding strength between the aluminum target blank and the aluminum alloy backboard is effectively increased, and furthermore the bending deformation after bonding is little.

The invention relates to a magnesium alloy and aluminum alloy interlayer diffusion welding method. The method mainly comprises the following steps of: (1) machining a welding metal base, namely processing, abrading, polishing and ultrasonically washing magnesium alloy and aluminum alloy; (2) depositing Cu films on the magnesium alloy and the aluminum alloy by controlling process parameters by using magnetron sputtering coating equipment; and (3) assembling the coated metal base by using a die, placing the die into a vacuum hot-pressing furnace, and controlling welding temperature, heat-preserving time and pressure to obtain a welding joint. The method has the advantages that: (1) the Cu film can protect the surface of the welding metal base better and reduce generation of inert metal oxide layers; (2) the Cu element improves phase constitution and the microstructure of a welding interface and inhibits generation of brittle intermetallic compounds in the midlayer of the welding joint; and (3) the welding joint has high strength, the tensile strength can reach 10 to 20 MPa, small deformation occurs in the welding joint, and the residual stress is small.

The invention provides a soldering/diffusion welding hybrid welding method for a cemented carbide and alloy steel. The method comprises the following steps of: performing the procedures of grinding, alkali washing and acid washing on the YG8 cemented carbide and the 42CrMo alloy steel sequentially, and then, electroplating a nickel coating on the surface of the YG8 cemented carbide; lapping the YG8 cemented carbide and the 42CrMo alloy steel, and paving a copper-based solder foil strip in a lapping area, thus obtaining a whole workpiece; and performing soldering/diffusion welding hybrid welding on the whole workpiece in a vacuum soldering furnace, thus obtaining a soldering/diffusion welding hybrid welding joint of the YG8 cemented carbide and the 42CrMo alloy steel. The welding joint subjected to the soldering/diffusion welding hybrid welding is high in bonding strength and small in residual stress, has a smooth and dense surface, and is smooth and attractive; and moreover, during the welding process, the welded workpiece is not easily oxidized and is subjected to small deformation, the service life of the workpiece is obviously prolonged, and thus the method is an ideal welding technology for realizing dissimilar welding of cutting teeth and cutting tools.

The invention discloses a heterogeneous metal connecting method for tungsten, copper and alloy thereof, which comprises the following steps: firstly, processing the surface of tungsten metal and performing surface treatment; plating nickel to the tungsten metal, processing the surface of the tungsten metal, and cleaning the tungsten metal; then, processing and cleaning the copper alloy; and finally, overlapping and assembling the tungsten and the copper alloy to form weldment, and connecting the weldments in a vacuum chamber through pressure diffusion welding to form a connecting piece. The method has the remarkable characteristics that before vacuum diffusion welding connection for the tungsten and the copper, a layer of thin nickel is firstly electroplated on the surface of the tungsten metal, and then is subjected to vacuum diffusion welding with the copper alloy so as to implement diffusion connection of tungsten-copper heterogeneous metals. The method has the advantages of simple and convenient process operation, low cost and good connecting effect, and develops a new path for the connection of the tungsten-copper heterogeneous metals; and the shearing strength can reach 50 to 80 percent of a tungsten base material.

The invention provides a vacuum hot-rolled composite method of a titanium alloy plate and a stainless steel plate, which relates to a composite method for the titanium alloy plate and the stainless steel plate. Aiming at the problems that intense mixing of liquid metal and high welding stress are generated during the melt welding of the titanium alloy plate and the stainless steel plate, the contradiction between the diffusion and the controlling of volume fraction of compounds in connection interface metals is boosted to ensure the connection during the vacuum diffusion welding and the explosion weld joint is difficult to be applied to high-temperature and corrosive temperature, the method is characterized in that the stainless steel plate (1) and the titanium alloy plate (2) are used; furthermore, a copper foil or aluminium foil (3) is used; the surfaces of the two plates are milled flatly and the copper foil or the aluminium foil (3) is laminated and fix between the two plates, so as form a specimen; the specimen is arranged in a vacuum loading chamber (5); when the vacuum degree in a vacuum heating furnace (6) is (1-3)*10<-3> Pa and the temperature is 600-1100 DEG C, the specimen is delivered into the vacuum heating furnace for heating and heat preservation, and then welded by a roller (7) and cooled. The method of the invention has small welding stress, can control the volume fraction of compounds in the metals with high hardness and large brittleness; furthermore, the weld joint can be applied to the high-temperature and corrosive environment.

The invention discloses a low-temperature diffusion welding method for magnesium alloy and aluminum alloy. The method comprises the following steps of: (1) workpiece surface cleaning: processing a magnesium alloy plate and an aluminum alloy plate to a specified size, and removing oxide layers from to-be-welded surfaces thereof; (2) workpiece assembly: placing a tin-zinc alloy foil serving as a middle layer between the aluminum alloy plate and the magnesium alloy plate, and placing a solder mask on and below the plates respectively to form a welded workpiece; and (3) charging the workpiece into a furnace and welding: putting the welded workpiece into a vacuum diffusion welding furnace, performing heating and heat preservation, applying an axial pressure to the welded workpiece when the heat preservation begins, and releasing the pressure when the heat preservation is finished. The method can effectively overcome the defect that the prior art cannot realize high-quality welding between the Mg alloy and the Al alloy, is suitable for reliable welding between the Mg alloy and the Al alloy of different categories, is particularly suitable for welding the thin magnesium alloy plate and the thin aluminum alloy plate, and has good welding planarity, high parallel precision and integral compactness.

The invention discloses a manufacturing process suitable for tungsten and steel connection of first wall part of a fusion reactor, belonging to the welding field of metal diffusion welding. The process comprises the following steps: 1, processing tungsten, steel and interlayer material workpieces according to requirements, and finishing a to-be-welded surface; 2, after processing, decontaminating and cleaning the workpieces by ultrasonic waves, and carrying out vacuum sealing; 3, manufacturing a stainless steel sheath; 4. putting the workpieces into the sheath in sequence, and sealing the sheath by electron beam welding or argon arc welding; 5, welding the sealed workpieces and sheath in a hot isostatic pressure machine, adopting high-purify argon gas by pressurizing gas, maintaining the temperature for 1.5-6h in the welding environment at 600-1080 DEG C and under the pressure of 100-300MPa, carrying out furnace cooling, and discharging from the furnace when the temperature is lower than 150 DEG C; and 6, carrying out necessary hot processing. According to the manufacturing process, the problem of poor connection performance of tungsten and steel caused by large difference of coefficients of thermal expansion can be solved, the connection strength and reliability of tungsten and steel can be improved.

The invention discloses a transient liquid phase diffusion bonding process of molybdenum copper alloy and stainless steel. The transient liquid phase diffusion bonding process comprises the following steps that (1) before welding, the surfaces to be welded of the molybdenum copper alloy and the stainless steel are cleaned, wiped and blown to be dry until the surfaces to be welded show metallic luster; (2) a composite middle layer is added between contacting surfaces to be welded of the molybdenum copper alloy and the stainless steel, and then a workpiece to be welded is put in a vacuum chamber and is pressed tightly through an upper pressing head and a lower pressing head; (3) when the vacuum chamber is vacuumized until the vacuum degree reaches 10-4 Pa, transient liquid phase diffusion welding is carried out on the assembled workpiece made of the molybdenum copper alloy and the stainless steel; (4) cooling is carried out after welding, and the welding workpiece made of the molybdenum copper alloy and the stainless steel is taken out. The transient liquid phase diffusion bonding process of the molybdenum copper alloy and the stainless steel completely achieves diffusion bonding between the molybdenum copper alloy and the stainless steel, can obtain a diffusion bonding connector made of the molybdenum copper alloy and the stainless steel with the shearing strength reaching 120 M Pa, can meet the use requirements of a composite structure made of the molybdenum copper alloy and the stainless steel, and has the advantages of being low in cost, simple, convenient, high in applicability, convenient to popularize and apply and the like.

The invention relates to a welding method of a target and a backing plate, comprising the following steps of: providing a copper target blank and a copper alloy backing plate; putting the copper target blank and the copper alloy backing plate in a vacuum can and then conveying to welding equipment; adopting hot isostatic pressing process to conduct diffusion welding, and welding the copper target blank on the copper alloy backing plate to form a target module; and after welding, conducting air cooling, removing the vacuum can and taking out the target module. On one hand, the welding method adopts the vacuum can to separate the target and the backing plate from air, thus effectively preventing the metal surface from being oxidized when in welding and reducing the vacuum equipment cost; on the other hand, the welding method utilizes the hot isostatic pressing process to conduct diffusion welding, thus further improving the bonding strength between the copper target blank and the copper alloy backing plate and leading to small bending deformation after bonding.

The invention relates to a method for transient liquid phase diffusion bonding between TiNi shape memory alloy and stainless steel, which belongs to the technical field of the connection of dissimilar materials. In the prior art, the technology of the connection between TiNi shape memory alloy and stainless steel has the problems of welding crack, large crystal grains in the heat affected zone and poor mechanical properties. The transient liquid phase diffusion bonding between TiNi shape memory alloy and stainless steel is realized through the following steps: after the surfaces of TiNi shape memory alloy and stainless steel to be welded and the surface of AgCuTi foil is cleaned and dried, a TiNi shape memory alloy/AgCuTi metallic foil/stainless steel structure is formed, fixed through a welding clip, and then positioned in a vacuum diffusion oven, and welding pressure and temperature are applied to the structure. The method has the advantages that the welding temperature is low (relative to fusion welding), the influence to the base material is small, the connector has no welding defect, the shearing strength of the connector in the room temperature reaches 250 MPa, and the microhardness of the area near the seam section can reach 670 Hv.

The invention discloses a tungsten-copper connection method, which comprises the following steps of: processing the surface of tungsten metal into a wave-shaped groove which is processed by superficial treatment: processing and washing the surface of copper metal: and then smelting and covering the copper metal on the wave-shaped surface of tungsten in a vacuum under temperature of 1150 to 1200 DEG C; processing and washing the smelt and the covered surface as well as copper alloy: and stacking and assembling the copper alloy into a welding piece which is connected by pressure and diffusion welding under temperature of 850 to 900 DEG C. The method has the advantages that solder or an intermediate layer is not adopted; the operation of the technique is simple and convenient; the cost is low; the connection effect is good; and a novel means of access for connecting tungsten and copper dissimilar metal is opened up, therefore, the method is convenient for popularization and application.

The invention discloses a dispersing welding method for a TiAl/Nb series alloy and a Ni-based high temperature alloy. First, a middle layer formed by overlapping a processed Nb foil with a Ni foil is arranged between the TiAl/Nb series alloy and the Ni-based high temperature alloy, the surfaces of which are processed; wherein, the Nb foil is contacted with the TiAl/Nb series alloy and the Ni foil is contacted with the Ni-based high temperature alloy to construct a welded workpiece; the welded workpiece is arranged between an upper squeeze head and a lower squeeze head in a vacuum dispersing welding boiler; a welding resistance layer is arranged between the upper squeeze head and the TiAl/Nb series alloy as well as between the lower squeeze head and the Ni-based high temperature alloy; the dispersing welding of the TiAl/Nb series alloy and the Ni-based high temperature alloy are finished in the vacuum dispersing welding boiler. Due to the dispersing welding method of adding a compound middle layer of Nb-Ni, no hard brittle phases are generated on a connection interface; the anti-tension intensity of a joint is improved from 183MPa art to 516-750MPa; the shearing intensity of the joint is improved from 359MPa to 372-528MPa.

Disclosed is a Ti-Al intermetallic compound alloy transition liquid phase diffusion welding composite connection method, by welding the Ti3Al alloy with the method, the room temperature strength and the high-temperature strength of the joint can reach over 80% of the mother metal's strength, equal plasticity with the mother metal can be obtained under room temperature, the joint can achieve uniform structure similar to the mother metal.

The invention relates to a diffusion welding method of a copper target and an aluminum alloy back plate and a prepared copper target assembly. The diffusion welding method comprises the following steps that (1) a titanium film is coated on the welding surface of the copper target, then the copper target coated with the titanium film and the aluminum alloy back plate are assembled, and then put into a package sleeve as a whole; (2) the package sleeve obtained in step (1) is sealed and then degassed; and (3) the degassed package sleeve in step (2) is subjected to hot isostatic pressure welding,then the package sleeve is removed, and the diffusion welding of the copper target and the aluminum alloy back plate is completed. According to the diffusion welding method, the welding bonding degreebetween the copper target and the aluminum alloy back plate is advantageously improved through the good diffusion of the titanium film; in addition, the titanium film is coated on the welding surfaceof the copper target, the uniformity of the titanium film can be improved, the welding bonding degree is advantageously enhanced, operation can be simplified, and the cost of materials can be saved;and the welding bonding degree of the copper target assembly prepared by the method is more than 99 %.

The invention discloses an activity transition liquid phase diffusion welding technique for a metallic matrix composite material (MMC), comprising: firstly, presetting an active interlayer provided with following alloy family composition characteristics among metallic matrix composite materials to be welded, the active interlayer contains both melting point depressant elements capable of reacting with the metal base and active elements reacting with ceramic intensify phase; the active elements are elements which can react with the ceramic intensity phase in the composite material rather than elements which can react with the metallic matrix or metallic matrix surface oxide film; secondly, pressurizing onto the welding surface; heating with a temperature lower than the melting point of the active interlayer to ensure obtaining liquid phase by using eutectic reaction; performing thermal insulation for certain time; and completing welding. The invented technique can improve humectation and coherence between composite material welding area 'intensify phase/metal' week boundaries. In addition, the invented technique can be used broadly in welding process between heterogeneous materials such as between ceramic/metal, ceramic/MMC, metal/hard metal, etc.

The invention provides an SPS diffusion welding method for a molybdenum alloy and a tungsten alloy. According to the method, titanium foil is used as an intermediate transition layer, solid phase diffusion welding is conducted on the molybdenum alloy and the tungsten alloy through an SPS technology, and a connecting piece of the molybdenum alloy and the tungsten alloy is obtained. By means of the welding method, a molybdenum alloy and tungsten alloy welding piece with the high strength and the good forming is obtained while it can be guaranteed that recrystallization of a base material is avoided, and the joint room temperature shear strength can reach 296 MPa.

This invention disclose a pressure device for vacuum diffusion welding, with the purposes of solving problem of long time weld, too high temperature, which is characterized in adding a vibrating cylinder (1) to present device, precise pressure regulating valve, vibration controlling valve controlled by PLC and PLC matching with (1), wherein, vibrating cylinder (1) and pressure valve (2) share a pressure axis (3), other parts are all rigidly attached, vibrating cylinder (1) is attached to gas source circuit via precise regulating valve and vibration controlling valve and parallel to pressure circuit. The invention can lower welding temperature by 30-300Deg.C, reduce welding time by 20-50%, and improve efficiency of device by 1-3 times.

The invention relates to a plate heat exchanger composed of a plurality of plates (1), preferably made from sintered ceramic material, in which fluid-flow guide channels (2) are formed as a system of channels in such a way that a substantially meandering profile of the fluid flow is obtained over the surface area of the respective plate, the side walls (3) of the guide channels (2) having a plurality of apertures (4), which lead to turbulence of the fluid flow.

The invention also relates to a method for the production of such a plate heat exchanger, in particular by a diffusion welding process in which the plates are joined to form a seamless monolithic block.

The plate heat exchanger according to the invention is suitable in particular for applications at high temperatures and/or with corrosive media, and also as reactors.