Showing papers on "Cold welding published in 1993"

The kinetics of composite particle formation during mechanical alloying

Abstract: The kinetics of composite particle formation during attritor milling of insoluble binary elemental powders have been examined The effects of processing conditions (ie, mill power, temperature, and charge ratio) on these kinetics were studied Particle size distributions and fractions of elemental and composite particles were determined as functions of milling time and processing conditions This allowed the deduction of phenomenological rate constants describing the propensity for fracture and welding during processing For the mill-operating conditions investigated, the number of particles in the mill generally decreased with milling time, indicating a greater tendency for particle welding than fracture Moreover, a bimodal size distribution is often obtained as a result of preferential welding Copper and chromium 'alloy' primarily by encapsulation of Cr particles within Cu This form of alloying also occurs in Cu-Nb alloys processed at low mill power and/or for short milling times For other conditions, however, Cu-Nb alloys develop a lamellar morphology characteristic of mechanically alloyed two-phase ductile metals Increasing mill power or charge (ball-to-powder weight) ratio (CR) increases the rate of composite particle formation

Thermal Analysis for Resistance Welding of Large-Scale Thermoplastic Composite Joints:

Abstract: The need for effective and reliable joining methods continues to grow as the use of thermoplastic composites becomes widespread. It is now possible to join large-scale components with the development of an automated sequential resistance welding process. The thermal history generated by the heating element placed at the interface between adherends determines the quality and performance of the welded joint. This article presents a thermal analysis for the resistance welding of large-scale components that overcomes the limitations of previous models. To simulate welding of the interface, a heat generation term was incorporated that accounts for the Joule heating of graphite fibers in the heating element. A parametric study was conducted to investigate the influence of welding parameters and assess the uniformity of interface temperatures. Components were joined by the resistance welding process to obtain experimental verification. Regions of localized overheating where potential current leakage may occur were identified as a function of process parameters. Insights on promoting more uniform heating for the resistance welding process are discussed. 11 refs.

Intermetallic alloy welding wires and method for fabricating the same

Abstract: Welding wires for welding together intermetallic alloys of nickel aluminides, nickel-iron aluminides, iron aluminides, or titanium aluminides, and preferably including additional alloying constituents are fabricated as two-component, clad structures in which one component contains the primary alloying constituent(s) except for aluminum and the other component contains the aluminum constituent. This two-component approach for fabricating the welding wire overcomes the difficulties associated with mechanically forming welding wires from intermetallic alloys which possess high strength and limited ductilities at elevated temperatures normally employed in conventional metal working processes. The composition of the clad welding wires is readily tailored so that the welding wire composition when melted will form an alloy defined by the weld deposit which substantially corresponds to the composition of the intermetallic alloy being joined.

Process for the electric welding of two weld parts

Abstract: The invention relates to a process for the electric welding of two weld parts by the flow of electric current through a welding point and the use of fluid such as an inert or protective gas to inhibit or prevent or eliminate oxidation at the welding point. The fluid is supplied through a continuous bore in one weld part and is directed toward the welding point, so that the fluid sweeps over the welding point radially from the bore. The fluid may be an inert gas such as argon or nitrogen, optionally mixed with carbon dioxide; alternatively the fluid may be aqueous liquid, the water being vaporized in the region of the welding point.

Numerical analysis of heating transient of electric contacts under short-circuit conditions

Abstract: A model for the simulation of the heating transient of contact elements under short-circuit conditions is described. The model permits the determination of the maximum temperature reached by the contact area under defined test conditions. In such a way it is possible to identify the conditions which do not cause contact welding. Numerical results obtained by simulation have been compared to the results of an experimental investigation on normal production contacts. >

Joining method and joining structure by spot welding using together press welding

Abstract: PURPOSE: To improve the strength of a coupler by spot welding by drawing down a spot welding electrode and the periphery of contact part of a material to be welded by using an insulater indenter when a power is supplied. CONSTITUTION: When the spot welding is performed, the material 13 to be welded is drawn down by bringing into contact with the spot welding electrode 11. Press welding is performed by drawing down the spot welding electrode 11 and the periphery of contact part of the material 13 to be welded by using the insulator indenter 12 when the power is supplied. In such a case, the width of a corona bond part 14 in the periphery of a nugget 15 is set at a value between 20-100% of a nugget diameter 17. In this way, solid joining can be performed by the synergetic effect of temperature and pressure, and a large corona bond part can be formed in the periphery of the nugget on which the spot welding is performed. Therefore, the coupler strength of a joint can be increased to expand a joining area from only a nugget area to the one on which a corona bond area is added. COPYRIGHT: (C)1995,JPO

Bead welding electrode of high hard and easily cutting

Abstract: The invented bead welding electrode is used on the welding layer with better processing performance. Its welding core may use 50 CrV, and the chemical components and compounding weight ratio of its flux cover are: titanium dioxide powder 3-5, calcium mica 4-7, fluorite 18-22, silicon iron 3-4.5, marble 29-33, mica 6-8, titanium iron 8-11, manganese iron 3-5.5, high carbon ferro chrome 1.5-2.0 and soda ash 1.2-1.5. The HRC of welding layer of above stated electrode is 52-57. As in use, the electric arc is easy for ignition, welding arc is stable, melting of flux cover is even, cold welding layer does not crack, technology is simple, cost is low, and is suitable for repairing metal parts, and surface strengthening of metal components.

Method for laser beam welding of plated steel sheet

Abstract: PURPOSE:To provide a method for the laser beam welding where the welding can be executed while keeping excellent surface shape of the molten pool without requiring a jig of high precision in a welding method to execute the lap joint welding of a pair of plated steel sheet by the laser beam. CONSTITUTION:A projecting part 14 is formed at least in a fist plated steel sheet. Then, a top part 15 of the projecting part 14 is abutted on the surface of a second plated steel sheet 20. The first plated steel sheet 10 is irradiated with the laser beam LA from the opposite side of the top part 15 of the projecting part 14. This constitution provides the lap joint welding of the first and second plated steel sheets 10, 20 while excellent surface shape of the molten pool is kept.

Solid-state resistance upset welding: A process with unique advantages for advanced materials

Abstract: Solid-state resistance upset welding is suitable for joining many alloys that are difficult to weld using fusion processes. Since no melting takes place, the weld metal retains many of the characteristics of the base metal. Resulting welds have a hot worked structure, and thereby have higher strength than fusion welds in the same mate. Since the material being joined is not melted, compositional gradients are not introduced, second phase materials are minimally disrupted, and minor alloying elements, do not affect weldability. Solid-state upset welding has been adapted for fabrication of structures considered very large compared to typical resistance welding applications. The process has been used for closure of capsules, small vessels, and large containers. Welding emphasis has been on 304L stainless steel, the material for current applications. Other materials have, however, received enough attention to have demonstrated capability for joining alloys that are not readily weldable using fusion welding methods. A variety of other stainless steels (including A-286), superalloys (including TD nickel), refractory metals (including tungsten), and aluminum alloys (including 2024) have been successfully upset welded.

Method for repairing a cracked metal part using repair plugs coated with a surface layer of zinc

Abstract: An improvement to the method for repairing a cracked metal wall commonly known as cold welding, which is accomplished by inserting metal locks across a crack to join the metal on opposite sides of the gap, and then inserting repair plugs which act as plugs to fill the gap and simultaneously pre-stress the inserted locks. The improvement comprises the use of repair plugs which have been coated with an electro-deposited layer of zinc. The zinc layer improves the sealing capability of the repair plugs, and is thereby advantageous for repairing cracks in the pressure areas of engine blocks or other vessels, containers or housings which contain fluids under pressure.

Laser welding method and device of lap joint part

Abstract: PURPOSE:To improve the accuracy of a lap joint shape and to increase a welding area in the case of tight laser beam welding of sinks, fuel tanks for automobiles, etc CONSTITUTION:The joint parts of members to be welded are powerfully clamped and are welded by irradiating the joint parts with a laser beam 6 from an extension line 5 of the contact surfaces of the clamped and superposed welded joint parts or a line having a slight angle with this extension line 5 in the case of welding of the joint parts of metallic plates 1, 2 superposed on each other by the laser beam The gap between the plates of the lap joint parts is thus eliminated Since the extremely marginal point of the weld line is clamped, the distortion at the time of welding is suppressed and dislocation is prevented Since penetration is possible broadly in the extension line direction of the contact surfaces of the lap joint parts, the welding strength is additionally enhanced

Method for lap joining of metallic sheet

Abstract: PURPOSE:To improve the tensile strength and the fatigue strength of a joined zone by executing the laser beam welding of the adhered surface after the adhesive is applied to the lapped surface of two metallic sheets to execute the adhesion. CONSTITUTION:One end parts of two metallic sheets 1, 1 are lapped and joined with each other. In this work, the adhesive is applied to at least one of the lapped surfaces of two metallic sheets 1, 1 to execute the adhesion. The laser beam welding is executed on the center part of the adhered part 2 with one bead 3. After the laser beam welding, the material to be joined is heated to harden the adhesive. The filler metal is used in the laser beam welding. For example, the two component, room temperature setting adhesive is applied to two strip-shaped test specimens 1, 1 of the hot-rolled steel sheet for automobile and the high tensile steel sheet, and the laser beam welding is executed after one end parts are joined with each other. This constitution prevents generation of defective welding such as blowhole.

Method of manufacturing welding electrode for underwater welding

Abstract: A welding electrode suitable for underwater welding is manufactured from a welding rod with a flux layer thereon by forming a protective coating of a waterproofing material at least over this layer and subjecting it to a pressure at least as great as the pressure at a depth of water at which the welding electrode is intended to be used such that the waterproofing material is driven into pores and interstices of the flux to impregnate it Waterproofing materials which do not produce organic residues at welding are preferred, such as liquid sealant with metallic aluminum powder, polyurethane, resins and epoxy-based coatings

Repairing method with welding, welding method and welding apparatus for metal member

Abstract: For repairing a metal member by welding, a secondary electrode is connected to the metal member to be repaired. A thin sheet type welding material of about 0.1-0.2 mm thickness is provided on a part of the metal member or a fine welding powder of a proper volume is piled up on there. The welding material or the welding powder is pressed to the metal member along a minute line or dots by a primary electrode and an electrical conduction path is formed. A large pulse current of about 300-1500 amperes is applied through the conduction portion during a short period of about 1/1000-4/1000 seconds to form nuggets of a minute line or dots on the metal member. Thus, a build-up welding can be done along dots or a line. A part of the build-up welded portion is worn away and ground to obtain a desired surface or shape. A permanent magnet or an electromagnet may be mounted at the primary electrode when the welding powder is used.

Welding gun tip

Abstract: A welding gun tip has an axial passage therethrough for the accommodation of a welding wire which extends through and projects beyond the free end of the welding tip. At the free end of the welding tip is an annular guide through which the welding wire extends. The guide is formed of material which is sufficiently harder than that from which the welding wire is formed to prevent the formation of a groove or channel in the guide as a result of movement of the welding wire relative to the welding tip. The guide is formed of dielectric material so as to avoid arcing between the welding wire and the welding tip.

The Welding Conditions of very Thin Aluminum Sheet of High Welding Speed DCEN TIG Welding without Filler Metal.

Abstract: The method of butt welding of very thin 0.3 mm thick aluminum sheets at very high welding speed (6000 mm/min) using ordinary TIG welder were newly developed. The process are as follows. Polarity is DCEN. The aluminum sheets were put in between 30 mm thick copper plates. By this method the aluminum sheets were butt welded up to 0.2 mm and bead welded up to 0.1 mm thick by bead on plate successfully. At comparatively low welding speed (500 mm/min), pushing roller had better to be added. Generally, welding heat input at high welding speeds are smaller than those of low welding speed. The appearance of successful welding are shown in photgraphs.

Manufacture of clad material of stainless steel and aluminum

Abstract: PURPOSE:To stably manufacture the clad material of stainless steel and aluminum which is excellent in joinability and workability CONSTITUTION:In manufacturing the clad material of stainless steel and aluminum by the different circumferential speed coiling rolling pressure welding method where the circumferential speed of the lower roll is set smaller than that of the upper roll, the aluminum raw material is coiled around the lower roll of the rolling mill, and the obtained clad material is coiled around the upper roll of the rolling mill, and at the same time, the rolling load [P] (tonf/ mm) per unit width of the raw material is adjusted to satisfy the relation [P>=10 R] with reference to the lower roll speed ratio [R] (%) and the cold welding rolling is executed, or after executing the cold welding rolling by adjusting the rolling load [P] per unit width of the raw material to satisfy the relation [P>=10 R] the heating is executed at the temperature range which is not less than the recrystallization temperature of the aluminum and >=500 degC In addition, the forward tension and the rearward tension in the welding rolling are adjusted to the respectively specified values

Steel tube for contact weld

Abstract: PURPOSE:To embody excellent workability in site welding and increase toughness in the welding zone by welding a ring which is manufactured of a Ni-base high alloy or the like and has the same diameter and thickness as the steel tube to both ends of a low alloy or carbon steel tube. CONSTITUTION:The ring 1 made of a stainless steel, 9% nickel steel and Ni-base high alloy which has the same diameter and thickness as the steel tube 1 made of the low alloy or the carbon steel and a length of 20 to 100mm is manually welded to the steel tube. After that, a test piece 3 is cut and contact weld is executed. A Charpy test piece 6 is picked from the welding zone 5. Then, toughness strength of this nickel high alloy base is >=5kgf.m as welded and good toughness in the contact welding zone can be attained.

Welding machine for welding 9 v cell positive /negative electrode

Abstract: The utility model provides a contact welding machine for welding both electrodes of a 9V cell, belonging to the field of welding technique, mainly composed of an infinitely variable speed motor, a cam, a connecting rod, a welding head body, a directional plate, a cooling water tank, a copper guide post and two welding heads. The utility model is characterized in that the two welding heads are respectively connected with two electrodes of a 220V or 380V power source. The tip shapes of the two welding heads all form semicircle table shapes, and the total area occupation are equal to the sectional area of the electrodes of a 9V cell, wherein, one welding head is longer than the other welding head with 0.3-0.8 mm. The two welding heads are used for together contacting the cell electrodes, and thus, an instant short circuit is created for generating heat. The electrodes and connecting lines are semi-melted and welded together. The electrodes and the connecting lines of a 9V cell welded by the contact welding machine has the advantages of firm welding points, high work efficiency, material saving and no pollution.

Electromagnetic relay for ON=OFF switching of lighting device - uses two pairs of parallel contacts respectively exhibiting high welding resistance and reduced transfer resistance and operated in sequence.

Abstract: The relay uses a pair of contacts of a material with a high resistance to contact welding and a pair of contacts with a reduced transfer resistance, connected in parallel with one another. Each of their movable contacts is pivoted in dependence on the movement of the relay armature relative to a magnetic pole system, such that the contacts with the higher welding resistance are closed before those with the lower transfer resistance. The two pairs of contacts face one another, with a setting element of the relay electromagnet located between them. This setting element pref. has a pair of arms providing the contact pivot movement in response to the movement of the armature. ADVANTAGE - Prevents welding of contacts with reduced transfer resistance due to switching current.

Multichip module and its manufacturing method.

Abstract: The invention relates to making contact to multichip modules. Contact is made to the individual chips of the multichip module by the flip-chip technique. Contact bumps are deposited on a substrate and the chips are mounted on the contact bumps so that the contact areas of the individual ICs of the chips are connected to the contact bumps of the substrate by cold welding.

Diffusion welding of laminated stainless steel wafers

Abstract: A laminated and diffusion welded turbine vane with fine cooling passages was designed and manufactured using 18Cr-8Ni stainless steel wafers. The turbine vane produced, was assessed using coolant flow analysis.In order to improve the joint quality, investigations were carried out using conventional diffusion welding to join the stainless steel wafers and camparisons made with diffusion welding followed by hot isostatic pressure (HIP) treatment.The tensile strength of the diffusion welds increased as the welding pressure was raised. However, the use of higher welding pressure brings about large deformation at the joint. As a result it is difficult to use conventional diffusion welding to produce good quality joints without deformation of the cooling passages at the joint region.When the welding area ratio at the joint interface is approximately 50% only isolated voids remain at the joint. Therefore, the use of HIP treatment is able to remove residual voids from the joint interface without macro deformation of the turbine vane. The use of HIP treatment allows joints to be produced with greater than 50% welded area ratio and with only 0.5% change in total length.This study has shown that by applying HIP treatment after preliminary diffusion welding it is possible to produce joints with no residual voids and with a minimum change in component shape.

Packaging technology of ultrathin film sensors by electron-beam welding

Abstract: In this paper, the packaging welding technology of ultrathin film sensors by an electron beam is discussed. It is interesting to note that the thickness of the film of a piezoelectric-type pressure sensor is only 0.05 mm. Welding for the film and shell has been provided by edge joint welding. The thicknesses of the substrate or tube wall of the film-type temperature-sensitive probe and the tube-type strain sensor are only 0.10–0.15 mm. Welding for the upper and lower substrates and thin tube of a strain sensor has been provided by semi-penetrating joint welding. The results of the electron-beam welding appear to be satisfactory.

Solid-state welding of a 0.27 carbon, chromium/molybdenum steel

Abstract: Solid state welding is often carried out in a vacuum chamber under rather low pressure (2 to 50 MPa) and temperatures. It offers considerable advantages, especially metallurgical ones. Indeed, with good process conditions, it generates no important microstructural degradation such as those occurring with classical techniques of fusion or friction welding. It is a soft joining process that generates only a small deformation of the samples. However, classical diffusion welding requires welding durations ranging from some dozens of minutes to several hours. Because of the cost incurred, the process can be employed only in industries such as the electronic, nuclear, aerospace and military industries