Showing papers on "Cold welding published in 1986"

Cold Welding 3 Influence of surface preparation on bond strength

Abstract: Surface preparation is a basic factor governing the mechanism of bond formation in the various cold-welding processes (though less important in upset butt=welding). In this final article of the series, after a discussion on some previous investigations into methods of surface preparation, a detailed account is given of an experimental investigation in which Al/Al strips were bonded by cold rolling after surface preparation by various methods. It was found that matt electrolytic Ni plating and scratch brushing were particularly suitable and gave almost identical results, though the plating method is more suitable for industrial use; anodising and chemical Ni plating could be used but result in lower bond-strength. Though the investigation was made only for the Al/Al combinations, it is believed that the matt Ni plating method is suitable for metal combinations and cold welding processes other than those used in this investigation.

Method of cold welding

Abstract: A method of cold welding of workpieces formed as axially symmetric bodies of rotation, wherein the workpieces are pressed into each other by applying an axial stress to at least one of the workpieces, and the workpieces are imparted a relative turn in a plane perpendicular to the direction of the axial stress.

Machine having a welding bar serving to form welded seams in a thermoplastic film

Abstract: In order to ensure that in a device of this type the welding bar (4) is in contact over its entire length with the film web (1) to be welded, via its welding edge under uniform contact pressure, the welding bar (4) is designed so that it can be deflected in the plane of action of this contact pressure force and is arranged such that during the welding operation it is pressed onto the film web (1) by the force of a pre-tensioning device (45). The result is that the welding bar (4) can, under varying operating conditions, for example at varying welding temperatures, automatically adapt to the profile, which may be distorted, of a counter-edge which supports the film web (1), so that even under varying operating conditions a contact pressure force results, between the welding bar (4) and film web (1), which is uniform over the entire length.

Contact wire for a roller seam welding machine

Abstract: The contact wire (30) for a roller seam welding machine is provided on its front face with grooves (32) which are formed in the longitudinal direction of the wire and which are bounded by sharp longitudinal edges (34). The contact wire (30) is particularly well suited for welding metal sheets, the surfaces of which are heavily soiled or provided with coatings which are poor electrical conductors or electrically non-conducting. During the welding operation, the longitudinal edges (34) cut open the sheets to be welded or their oxide layer or coating which is a poor electrical conductor or non-conducting, and render possible a direct passage of the welding current to the actual metal sheet. Dirt as well as semi-plastic and vaporized coating material are reliably carried away to the front and rear in the longitudinal grooves so that the contact wire (30) cannot "float" during the welding operation. A preferred application for the contact wire (30) is the welding of fuel tanks from sheets which are coated so as to be poor electrical conductors or non-conducting on both sides, on a resistance roller seam welding machine.

Method for producing a welded joint between the contact element of a semiconductor and an electrical connector

Abstract: A method for producing a welded joint between the contact element of a semiconductor, especially a solar cell, and an electrical connector, by means of a resistance welding process In order to avoid impurities exacerbating or even preventing a good welded joint, the connector is initially welded on to the contact element by means of at least one ultrasound welding pulse Subsequently, the resistance welding process is carried out in order actually to weld the contact element and the connector A soft ultrasound welding pulse can be used, which produces a minimum mechanical adhesion strength between the contact element and the connector

Relation between Surface Temperature and Reverse Side Bead Width in Girth TIG Welding for Stainless Steel Tube -Study on Penetration Control of Weld (Report III)-

Abstract: Surface temperature near the rear end part of molten pool in girth TIG welding for 2 mm thick, 25.4 mm diameter stainless steel tube was measured with a PbS infrared radiation pyrometer. Effects of welding position and distance from arc center to a measuring point on the relation between the surface temperature and the reverse side bead width were investigated at down-hand, vertical down, over head, vertical up welding position of orbital TIG welding.Temperature near the rear end, part of molten pool becomes high in order down-hand, vertical up, vertical down, over head welding position under the same reverse side bead width condition. Mutual correlation exists at each welding position between surface temperature at the position 5-10 mm away from the center of the arc and the reverse side bead width. It indicates the possibility of adaptive control of the reverse side bead width by monitoring the temperature near the rear end part of molten pool during the TIG welding.

Manufacture of micro-heat pipe

Abstract: PURPOSE: To contrive to be able to easily form a nicro-heat pipe for enhancing the substantial heat conductivity of a semiconductor substrate by a method wherein a condensable fluid which is used as a working fluid is injected in recessed parts formed in the substrate with the recessed parts completely opened and the recessed parts are sealed by resistance welding without making the whole substrate heat up. CONSTITUTION: Recessed parts 3 provided with a part of a fine width enough to generate a capillary pressure are formed in a semiconductor substrate 1, and welding material layers 5, through which a current is made to flow to generate heat and fuse, are each formed on the peripheries of the opening ends on the surface of the substrate 1 in these recessed parts 3. Condensable fluids which perform heat transmission as latent heat of vaporization are each put in the recessed parts in a vacuum atmosphere. Then, other semiconductor substrate, wherein welding material layers of the same pattern as that of the welding material layers are formed, and the substrate are superposed and pressed in such a way that the welding material layers come into contact opposing to each other. By making a current flow through these welding material layers to generate heat, the substrates are instantaneously welded together by these welding material layers and, moreover, the recessed parts are sealed. In such a way, as the substrate are welded together by the welding material layers, the scattering of the condensable fluids from the recessed parts is little generated. COPYRIGHT: (C)1988,JPO&Japio

Nodular cast iron welding rod with low-carbon steel core

Abstract: The low-carbon steel (H08A) [GB1300-77] is used as core of welding rod which is coated with nodulizing agent and alloying chemical layer. This welding rod can be used in cold welding and hot welding processes for various grades of nodular cast iron. After corresponding heat treatment, the welding joint has the same strength, plasticity, metallographic structure and hardness of the maste piece. This welding rod can also be used in the welding of gray iron myrmekitic cast iron, alloy cast iron and malleable iron.

Contact wire for a seam welding machine

Abstract: The contact wire (30) for a seam welding machine is provided on its front side with grooves (32) which are formed in the longitudinal direction of the wire and are bounded by sharp longitudinal edges (34) The contact wire (30) is particularly suitable for the welding of sheets whose surfaces are very dirty or provided with coatings which are poor conductors of electricity or have an insulating effect During the welding operation, the longitudinal edges (34) cut open the sheets to be welded or their oxide layer or coating with its poor electrical conductivity or insulating properties and permit direct access to the actual sheet by the welding current Dirt and viscous or vaporized coating material are removed reliably towards the front and rear in the longitudinal grooves, thereby preventing the contact wire (30) from floating during the welding operation One preferred application of the contact wire (30) is for the welding of fuel tanks made of metal sheets provided on both sides with a coating which is a poor electrical conductor or has insulating properties on a resistance seam welding machine

The Compaction of Rapidly Solidified Materials

Abstract: Powder compaction has two equally important aspects: the elimination of pores and the creation of bonds between the particles Important bonding mechanisms are cold welding and mechanical interlocking of particle surfaces The first requires plastic flew in order to break the surface oxide, the second depends on irregular surface geometry Hard, smooth particles do not usually permit the action of either of these mechanisms; after compaction, they simply fall apart again Such powders must be contained in capsules and, after compaction, must be bonded by sintering or hot pressing This has in fact become the normal fabrication route for superalloy and tool steel powders

Microstructural modifications during laser and electron beam welding

Abstract: Extensive microstructural modifications occur during laser and electron beam welding of various alloys For austenitic stainless steels, most welds that do not hot crack contain a duplex austenite plus ferrite microstructure when welded by conventional welding processes However, during laser welding at high speeds, fully austenitic or ferritic microstructures can be obtained in this class of material The observed modifications in microstructures will be explained in terms of changes in the mode of solidification and also a retardation of solid state transformation Laser and electron beam welding processes have been successfully used to weld iridium alloys, which are difficult to weld by conventional welding processes During welding, these alloys have been found to be prone to severe hot cracking The cracking is influenced to a great extent by the fusion zone microstructure and composition The successful laser and electron beam welding of these alloys is attributable to the highly concentrated heat source available, precise control of the heat input, and the refinement in fusion-zone microstructure obtained The refinement in the fusion-zone microstructure and hence the reduction in hot-cracking tendency of these alloys are discussed in terms of the puddle shapes and grain growth during laser or electron beam welding