Showing papers on "Cold welding published in 2002"

Nanolithography based on patterned metal transfer and its application to organic electronic devices

Abstract: We demonstrate a patterning method capable of producing features of submicron scale based on the transfer of a metal film from a stamp to a substrate assisted by cold welding. The patterned metal film can be used as an etch mask to replicate the pattern on the substrate, or the film itself can serve as contact electrodes for a wide range of electronic devices. We demonstrate the versatility of the technique by fabricating a polymer grating on SiO2 with lateral dimensions <80 nm and a pattern resolution approaching 10 nm, and by fabricating organic solar cells and pentacene channel organic thin-film transistors with channel lengths as short as 1 μm.

Laser power coupling efficiency in conduction and keyhole welding of austenitic stainless steel

Abstract: Laser welding of thin sheets of AISI 304 stainless steel was carried out with high power CW CO2 laser. The laser power utilized in the welding process was estimated using the experimental results and the dimensionless parameter model for laser welding; and also the energy balance equation model. Variation of laser welding efficiency with welding speed and mode of welding was studied. Welding efficiency was high for high-speed conduction welding of thin sheets and also in keyhole welding process at high laser powers. Effect of pre-oxidization of the surface and powder as filler material on laser power coupling is also reported. The paper also discusses effect of microstructure on the cracking susceptibility of laser welds.

Welding Characteristics of Aluminum and Copper Plate Specimens Welded by a 19 kHz Complex Vibration Ultrasonic Seam Welding System

Abstract: The welding characteristics of aluminum and copper plate specimens welded using a 19 kHz ultrasonic welding system with a complex-vibration welding tip were studied. The welding tip part vibrates in an elliptical or circular locus. The seam welding system uses a rotating circular disk welding tip and a shifting stage for continuous welding of the metal sheets. Using the complex-vibration system, metal plates of various thicknesses can be welded continuously at multiple positions with large and uniform welded areas and large weld strengths independently of the welding position and direction. The required complex-vibration amplitude is less than one-half of that of a conventional linear-vibration system. Aluminum-aluminum, aluminum-copper and copper-copper plate specimens were welded with weld strengths almost equal to the specimen strength.

Mechanically assisted droplet transfer process in gas metal arc welding

Abstract: Gas metal arc welding has been generally accepted as the preferred joining technique due to its advantages in high production and automated welding applications. Separate control of arc energy and arc force is an essential way to improve the welding quality and to obtain the projected metal transfer mode. One of the most eVective methods for obtaining separate control is to exert an additional force on the metal transfer process. In this paper, the droplet transfer process with additional mechanical force is studied. The welding system is composed of an oscillating wire feeder. The images of molten metal droplets are captured by a high-speed digital camera, and both the macroscopic appearance and the cross-sectional pro®les of the weld beads are analysed. It is shown that the droplet transfer process can be signi®cantly improved by wire electrode oscillation, and a projected spray transfer mode can be established at much lower currents. By increasing the oscillation frequency, the droplet transfer rate increases while the droplet size decreases. In addition, the improvement in the droplet transfer process with wire oscillation leads to an enhancement of the surface quality and a modi®cation of the geometry of the weld beads that could be of importance for overlay cladding and rapid prototyping based on deposition by welding.

Finite element analysis of resistance spot welding in aluminium

Abstract: In the present work, an integrated simulation model has been developed for analysis of the resistance spot welding process in aluminium alloys via the finite element method. A coupled electrothermal analysis for an axisymmetric sheet-electrode geometry has been carried out that can predict the expected nugget diameter, penetration, and electrode face heating at any instant throughout the welding time. Several calculations have been carried out for different welding currents, welding times, and electrode forces and for different surface conditions of the aluminium sheets. Non-linear, temperature dependent, thermophysical material properties have been considered. An observation of interest is that in most instances the maximum nugget diameter is reached well within 0·02-0·04 s and further flow of welding current simply increases the electrode face heating. Also, the initial surface condition influences the growth of the fusion zone to a great extent. Various other conclusions have also been drawn.

Friction agitation joining method, flat material for plastic working, and closed-end sleeve-like body

Abstract: A friction stir welding method conducts contact welding on two welding target members having different high temperature deformation resistances by using a welding tool having a rotatable welding head, contacting the two welding target members having different high temperature deformation resistances against each other so as to generate a difference in height between the two welding target members on a surface side in a thickness direction, arranging the rotating head in a state in which the head is embedded into a contact section of the two welding target members or a neighborhood of the contact section from the surface side, and relatively moving the welding head to the two welding target members along the contact section in this state, is provided. A rotating direction of the welding head is set in a direction in which the welding head rotates from the welding target member which is higher in high temperature deformation resistance to the welding target member which is lower in high temperature deformation resistance in the rear of a welding direction and the contact welding is conducted on the two welding target members.

Method and system for laser welding of two or more overlapped metal sheets, and device for clamping the sheets used in this method

Abstract: Welding of two or more steel sheets, at least one of which has a protective layer of a material with a low vaporization temperature, is carried out by directing a laser beam on two overlapped flanges of the sheets, which are clamped in position during welding by means of clamping devices. These clamping devices are able to hold the flanges to be welded in a slightly spaced apart position from each other, so as to create a gap, which does not jeopardize the possibility of carrying out the welding while enabling evacuation of the vapours of the protective material, which are generated during welding.

Friction stir welding apparatus, and its welding method

Abstract: PROBLEM TO BE SOLVED: To provide a friction stir welding apparatus and its welding method, by which high quality welding can be efficiently carried out by effectively utilizing heating means other than frictional heating even for the workpiece into which heat is easily accumulated because of their shapes and properties of material, or on the contrary, the workpiece from which heat is easily dissipated even during preheating. SOLUTION: The friction stir welding apparatus uses a probe type or bobbin type rotary tool 20 having a small diameter portion 22, which is inserted into a welding portion so as to be stirred, and a large diameter portion 21, which is pressed against the welding surface so as to slide. The heating to be carried out at a front position on a welding line is carried out by a heating means such that the temperature is not higher than the softening temperature carried out by self-heating, such as high frequency induction heating. Another heating to be carried out on a welding position together with the frictional heating is carried out by self-heating, such as high frequency induction heating, or by electric resistance heating applied to a base material from the small diameter portion. Further, the apparatus includes a cooling means for cooling a heat affected zone in the back of the welded position after the friction stir welding has been finished. COPYRIGHT: (C)2004,JPO

Electron beam welding to join gamma titanium aluminide articles

Abstract: A method is provided for welding two gamma titanium aluminide articles together. The method includes preheating the two articles to a welding temperature of from about 1700° F. to about 2100° F., thereafter electron beam welding the two articles together at the welding temperature and in a welding vacuum to form a welded structure, and thereafter annealing the welded structure at an annealing temperature of from about 1800° F. to about 2200° F., to form a joined structure.

Endpiece for a chromatography column

Abstract: A liquid transfer system (100) comprising a net (170) and a net support (160), wherein, the net (170) is integrally joined with the net support (160). The net (170) and the net support (160) are preferably joined by welding, such as contact welding or by welding at a lower edge (400) of a number of welding-holes (350) that extends through the net support (160).

Welding process, especially a spot welding process, for welding joining partners comprises determining the temperature of a joining partner during the process and controlling a welding parameter of a laser beam based on the temperature

Abstract: Welding process comprises determining the temperature of at least one joining partner (2a, 2b) during the process and controlling a welding parameter of a laser beam (1a) used in the process based on the temperature. An Independent claim is also included for a device for carrying out the welding process.

Welded structure, process and equipment for welding

Abstract: PROBLEM TO BE SOLVED: To provide a welded structure with high joining strength in which a stress does not concentrate to a weld bead, that is, a heat-affected zone does not arrive to a continuation breaking due to the shortage of the strength of a welding starting point and terminating point or due to a weld flaw, and to provide a welding process and welding equipment for reducing the influence of the weld flaw caused by welding with a high energy beam. SOLUTION: The weld bead of at least one of a starting end part 2 and a terminating end part 4 among weld beads 1 formed by single pass is bent to form in the lateral side to the weld bead of an intermediate part 2, in the welded structure K which joins two members of K1 and K2 by a lap welding. COPYRIGHT: (C)2004,JPO

Welding of aluminum alloy with high power direct diode laser

Abstract: Characterized by high conversion efficiency, small size, light weight and a long lifetime, high power diode lasers are currently being developed for application to various types ofmetal fabrication, such as welding. In this report, a 4kW high power direct diode laser was used to weld aluminum alloys, which are the focus of increasing attention in the automobile industry because of their light weight, high formability and easy recyclability. The applicability of a direct diode laser to aluminum alloy bead-on-plate, lap-fillet and butt welding was studied under various welding conditions. A sound bead without cracks was successfully obtained when 1mm thick aluminum alloy was welded by bead-on-plate welding at a speed of 5m/min. Moreover, the bead cross section was heat conduction welding type rather than the keyhole welding type of the conventional laser welding. Investigation of the welding phenomena with a high-speed video camera showed no spattering or laser plasma, so there was no problem with laser plasma damaging the focusing lens despite the diode laser's short focusing distance.

Joining of γ-TiAl to low alloy steel by electron beam welding

Abstract: The weldability of cast γ-TiAl with a low alloy steel by electron beam welding was investigated in this study. It was found that when a higher heat input was employed, solid state cracking appeared in the welds due to a high thermal stress, as well as formation of a brittle TiC phase and a small fraction of Ti3Al intermetallic. Crack free welding could be achieved if welding parameters were properly controlled such that thermal stress was released and formation of TiC and Ti3Al was minimised.

Welding structure and welding method of bus bar

Abstract: PROBLEM TO BE SOLVED: To provide a welding structure and a welding method of a bus bar for welding the bus bar and a mate member being welded with good appearance while stabilizing the bonding force. SOLUTION: Since protrusions 33 and 33 of a bus bar 30 on the opposite sides of a slit 32 are tapered, the protrusions 33 and 33 melt readily as compared with a conventional case and bonding force is stabilized at a welded part. The welded part becomes compact because the bus bar does not require a conventional raised wall. Furthermore, difference in the shape is reduced between the welded protrusions 33 and 33 because both protrusions 33 and 33 melt readily and appearance is enhanced at the welded part. COPYRIGHT: (C)2004,JPO

Backing plate and its manufacturing process

Abstract: A backing plate of Ti for supporting a Ti sputtering target is formed of at least two components welded together. The backing plate is welded by interposing a Cu or Zr foil or powder between faces to be welded, and then heating the assembly to a reaction temperature high enough to melt one of the Ti and Cu or Zr to produce a liquid phase. The heating temperature is retained for a time long enough to permit diffusion of the Cu or Zr into the Ti to produce a liquid phase diffusion weld. By permitting diffusion to occur, a separate metallic compound is not produced at the welding face. In effect welding is accomplished without producing a welding face, whereby no interface exists in the finished weld. The resulting weld has a strength substantially equal to the strength of the Ti material, and very good welding qualities.

Method for joining different kinds of metallic material

Abstract: PROBLEM TO BE SOLVED: To provide a resistance welding method for different kinds of metallic material without largely changing the conventional production process and without producing an intermetallic compound by using no intermediate layer and no cladding material. SOLUTION: The resistance welding method for different kinds of metallic material is characterized in that a minute molten portion is produced between the different kinds of material by causing high current to flow for very short period of time and simultaneously, high pressure force is applied to the molten portion to scatter the molten portion as dust, and a solid-phase joined part is obtained by the contact of clean metal surfaces with each other and the diffusion of atoms. Thus, if this method is applied to the welding process, for example, for a car body, since the welding of the different kinds of metallic material can be performed without requiring a large change in the conventional processing line, this method can efficiently cope with the demand for weight saving of the car. COPYRIGHT: (C)2004,JPO

Clad material for welding structure and welding structure member using the clad material

Abstract: PROBLEM TO BE SOLVED: To provide a material for a welding structure which is light in weight, and moreover, excellent in weldability, and also, to provide a welding structure member formed of the material. SOLUTION: A clad material is provided. The clad material is provided with a base material layer 2 formed of pure Al or an Al alloy and a welding layer 3 diffusion-joined to the base material layer. The welding layer 3 is formed of an Ni-Cu alloy containing Ni of 20-70 mass %. The welding layer 3 may be formed at a part on the surface of the base material layer 2. Also, it is preferable that both surfaces of the base material layer 2 are coated with the welding layer 3. COPYRIGHT: (C)2004,JPO&NCIPI

Influence of arc duration and current on contact welding in low power switches

Abstract: A model test switch has been developed to investigate the influence of kinetic parameters (as contact velocity and contact force) on contact welding under conditions prevailing in relays, micro switches etc. Both frequency and intensity of the statistically scattered weld forces increased with increasing arc duration and current. Pre-strike and bounce arcs show identical results under corresponding conditions. Therefore, the configuration of the load circuit determining the actual arc current curve essentially influences the weld force values.

Welding device for sheet metal panels using high energy welding beam with formation of venting gap for welding gases

Abstract: The welding device has pressure devices (4,5) used for clamping flange sections of 2 or more sheet metal panels (1,2,3) together, a venting device (12,13) providing wedge-shaped gaps between the latter for venting the welding gases. Welding lenses are attached to the pressure devices for focusing opposing welding beams (10,11) onto the clamped area of the flange sections.

Welding current nozzle material

Abstract: The invention relates to a welding current nozzle material used in the welding current nozzle for feeding filler material in MIG-type welding. The material used In the welding current nozzle according to the invention is a copper-based alloy where silver is alloyed.

Long life welding electrode and its fixing structure, welding head, and welding method

Abstract: A fixing structure for a welding electrode and a welding head is shown which enable improvement of durability of a welding electrode, improvement of work efficiency in welding, and a reduction of time required for welding and also which make it possible to execute welding for an extended time with high reliability In the fixing structure, a fixed section of a welding electrode is inserted via a thermally conductive material into an inserting section of a fixing base and a peripheral surface of the fixed section of the welding electrode is uniformly contacted to the fixing base to affix the welding electrode to the fixing base

Study on Laser Welding of Ultra - fine Grained Steel with Weaving Beam

Abstract: According to the theoretical analysis of the thermal flow and the forces in the molten pool formed during laser welding, the feasibility of improving the weld structure and the performance by weaving the laser beam during welding is discussed. Experiment results show that the beam weaving could restrain the growth of the column grains and refine the grains. By using this technique, the mechanical properties of the welded joint could be increased.

Mechanism of laser beam welding for SiCP/6063Al composite

Abstract: The laser beam welding technique was used to process SiC particles /6063A1 alloy matrix composite, the influence of laser power and welding speed on the properties of joint was studied Decreasing the laser beam power with same welding speed can make the quantity and size of A14C3 decreased, and the interactive mechanism of the reinforcing particles and the matrix in the joint and the causes for joint strength reduction were analyzedIncreasing welding speed properly can improve the distribution of energy and restrain the interfacial reaction in the molten pool, and measures for improving were proposed

Plate stacked body, hollow stacked body using plate stacked body, and plate heat pipe using hollow stacked body

Abstract: An environmentally unrestricted plate heat pipe with excellent radiation characteristics, a hollow stacked body used for the plate heat pipe, and a plate stacked body used for the hollow stacked body, wherein the plate stacked body is formed by a cold welding by using a pressure welder having, on the pressure welding surface thereof, a non-pressing part corresponding to the press-fitting suppressing part of a specified pattern of a plurality of metal plates (12, 13) after an activation treatment is applied to the opposed surfaces of the plurality of metal plates (12, 13) under a very low pressure, the hollow stacked body (10) having a hollow part (11) is formed by dwelling the press-fitting suppressing part, and the plate heat pipe is formed by sealing water as working body in the hollow part.

Cold-welding of aluminium and copper

Abstract: The current revival of domestic industry has resulted in an increase in the demand for the application of many welding technologies which have not been used in the last decade. They include cold pressure welding, which is one of the most efficient methods of joining ductile nonferrous metals and alloys." Taking into account the data obtained in the last couple of years, examples will be given of the application of cold-welding characterised by the largest number of orders.

Method for making electrode with wear resistant insert

Abstract: welding processes and equipment, possibly manufacture of electrodes for spot contact welding machines and arc plasmotrons for welding and cutting. SUBSTANCE: method comprises steps of forming in blank working portion of electrode and its cooling duct; forming protrusion on end of blank at side of working portion of electrode and making opening in said protrusion for placing in it wear-resistant insert; fixing insert simultaneously with formation of working portion of electrode and pressing out its cooling duct; performing the last two stages by cold die forging process ; making opening for wear resistant insert by pressing it out or by drilling; wrapping with liner cylindrical surface of wear resistant insert before placing it into opening. EFFECT: significantly increased contact surface area between joined members of electrode. 5 cl, 7 dwg