311results about "Pressure electrodes" patented technology

Welding electrodes with a welding face for contact with a metal surface for electrical resistance welding are provided with concentric contoured rings formed into the face. The rings may, for example, be ridges upstanding in the face or grooves depressed into the face. The contoured rings may be radially spaced with relatively flat (depending on the curvature of the face) intervening rings. When the electrode is pressed into contact with the surface of the workpiece for delivery of a welding current, the features of the concentric rings penetrate surface oxides or other conductivity barriers. When ongoing welding operations have eroded the contoured rings they may be rapidly reformed in the weld face in a surface re-dressing operation.

To provide a joint product of a steel product and an aluminum material, and a spot welding method for the joint product, ensuring that spot welding with high bonding strength can be performed. In one embodiment, a steel product 1 having a sheet thickness t₁ of 0.3 to 3.0 mm and an aluminum material 2 having a sheet thickness t₂ of 0.5 to 4.0 mm are joined together by spot welding to form a joint product of a steel product and an aluminum produce. In this joint product, the nugget area in the joint part is from 20×t₂^0.5 to 100×t₂^0.5 mm², the area of a portion where the thickness of the interface reaction layer is from 0.5 to 3 μm is 10×t₂^0.5 mm² or more, and the difference between the interface reaction layer thickness at the joint part center and the interface reaction layer thickness at a point distant from the joint part center by a distance of one-fourth of the joint diameter D_c is 5 μm or less. According to this construction, there can be provided a dissimilar material joint product with excellent bonding strength, which can be formed by an existing spot welding apparatus at a low cost without newly using other materials such as clad material or without newly adding a separate step, and a spot welding method for the dissimilar material joint product.

An indirect spot welding method is provided in which, in indirect spot welding, nuggets formed in a fused state can be stably obtained. In the indirect spot welding method, the welding time is divided into two time periods t₁ and t₂, where electrode force F₁ and current C₁ are applied in the first time period t₁, and electrode force F₂ lower than electrode force F₁ and current C₂ higher than current C₁ are applied in the next time period t₂.

An apparatus and method for fastening layers of non-ferrous alloys, like aluminum, magnesium and copper utilizes a steel fastener and a spot welding machine. The fastener and metals are stacked and the heat from the welder's electric current softens the lower melting point aluminum allowing the fastener to penetrate the aluminum. A weld zone between the fastener and the various layers creates an internal weld. The fastener has a rough shaft that is coated by the molten weld zone and is hard to withdraw on solidification. Layers of non-conductive materials like plastics and ceramics may also be affixed to a conductive layer using a fastener made from a compatible material that extends through a pilot hole and welds to or penetrates a conductive layer. The fastener may have projections that initially reduce contact area with the stack.

The formation of spot welds in high strength steel workpieces is improved by using welding electrodes with annular, or donut shaped welding tips for the formation of the molten metal weld pool at the weld site. The annular poll solidifies to form an annular weld nugget. Preferably the donut shaped nugget has an internal diameter that is no more than three-quarters of the outside diameter. The method is applicable to carbon steel workpieces with allowing elements for strengthening, and to thick sheets of mild carbon steels.

A method of resistance spot welding a steel workpiece and an aluminum or aluminum alloy workpiece (“aluminum workpiece”) together includes several steps. In one step a workpiece stack-up is provided. The workpiece stack-up includes a steel workpiece and an aluminum workpiece. Another step involves forming a protuberance in the steel workpiece. In another step a first and second welding electrode is provided. Yet another step involves clamping the first and second welding electrodes over the workpiece stack-up and over the protuberance. And another step involves performing one or more individual resistance spot welds to the workpiece stack-up.

An electrode whose electrode surface is a substantially convex curved surface and which has at a center portion a recess set at a predetermined depth allowing a welding trace formed on a metal body surface to reach a deepest portion when a nugget is formed in a satisfactory manner by the spot welding is used as at least an electrode for performing the spot welding. The spot welding quality is judged based on a shape of the welding trace formed on the metal body surface by the spot welding in correspondence with the recess.

A welding electrode has a body having a shank and a contact region for placement against a workpiece during welding. A portion of the body may be formed on a parabolic profile. A coating is formed on the contact region. The coating may have a first layer, and a second layer formed over the first layer. The first and second layers may have different compositions. The electrode may have internally formed cooling finwork for interaction with a liquid cooling system.

A resistance welding electrode body is fitted with a metal pin which serves as an anchor point for an electrode welding tip. The electrode welding tip contains two lead-in notches and diagonal grooves that allow the electrode tip to be locked onto the electrode body. This form of electrode has been found advantageous in terms of retaining the electrode tip onto the electrode body during resistance spot welding.

A series of many electrical resistance spot welds is to be formed in members of an assembled, but un-joined, body that presents workpiece stack-ups of various combinations of metal workpieces including all aluminum workpieces, all steel workpieces, and a combination of aluminum and steel workpieces. A pair of spot welding electrodes, each with a specified weld face that includes oxide-disrupting features, is used to form the required numbers of aluminum-to-aluminum spot welds, aluminum-to-steel spot welds, and steel-to-steel spot welds. A predetermined sequence of forming the various spot welds may be specified for extending the number of spot welds that can be made before the weld faces must be restored. And, during at least one of the aluminum-to-steel spot welds, a cover is inserted between the weld face of one of the welding electrodes and a side of a workpiece stack-up that includes the adjacent aluminum and steel workpieces.

A method of resistance spot welding a steel workpiece and an aluminum or aluminum alloy workpiece together includes several steps. In one step a workpiece stack-up is provided. The workpiece stack-up includes a steel workpiece and an aluminum or aluminum alloy workpiece. Another step involves providing a first welding electrode that confronts the aluminum workpiece, and providing a second welding electrode that confronts the steel workpiece. The first welding electrode has an electrode body and an insert that functions to limit or eliminate heat flux into the electrode body. Other steps of the method involve bringing the first and second welding electrodes into contact with opposite sides of the workpiece stack-up and resistance spot welding the stack-up.

A resistive welding electrode includes at least a weld face constructed of a refractory-based material that exhibits an electrical conductivity that is less than or equal to 65% of the electrical conductivity of commercially pure annealed copper as defined by the International Annealed Copper Standard (IACS). A method of using the resistive welding electrode to resistance spot weld a workpiece stack-up that includes an aluminum alloy workpiece and steel workpiece that overlap and contact each other at a faying interface is also disclosed.

A method for welding a plurality of aluminum to aluminum welds and a plurality of steel to steel welds using the same welder includes providing a resistance spot welder with a pair of weld electrodes having an electrode face radius of curvature in the range between 20 mm and 40 mm. The series of aluminum to aluminum welds is first made, and then, after completing the aluminum to aluminum welds, the series of steel to steel welds are made. After completing the steel to steel welds the weld electrodes are cleaned by an abrasive to remove any buildup or contamination of aluminum on the electrodes. In the event the electrodes have mushroomed, then dressing of the electrodes is provided and then the abrasive cleaning is performed to restore the surface texture.

An electrode tip holder, a welding method, and an electrode tip adjusting device. The electrode tip holder comprises a chuck body having an inner diameter hole with a first tapered inner peripheral surface diverging toward the tip thereof, a lock nut threaded with the tip male screw part of the chuck body, and a collet fitted to the inner diameter hole. The collet is axially pressed since the lock nut is threaded with the tip male screw part and reduced in diameter by the elastic deformation of a slit to hold an electrode tip fitted to the inside thereof. The chuck body comprises a coolant supply port supplying a coolant to a groove part and a coolant recovery port recovering the coolant from the groove part which are opened at positions facing the groove part.

The invention discloses a mesh welding machine with the functions of simultaneously pressing multiple electrodes down and respectively welding a single electrode. The mesh welding machine structurally comprises a transformer, a plurality of upper electrodes and a plurality of lower electrodes, wherein the plurality of lower electrodes are arranged on a lower electrode seat, and the lower electrode seat is connected with one output end of the transformer; each upper electrode is provided with an upper electrode seat, and the multiple upper electrode seats are arranged on a drive mechanism; a second conductive copper bar is arranged between each upper electrode seat and a welding cylinder, wherein one end of each second conductive copper bar is connected with the corresponding upper electrode seat, and the other end of each second conductive copper bar is connected with a piston rod of the welding cylinder in an insulated manner; the bottom surfaces of the second conductive copper bars are adjacent to an upper electrode plate, and the upper electrode plate is connected with another output end of the transformer. The mesh welding machine disclosed by the invention has the beneficial effects that multiple welding points of a metal mesh are simultaneously pressed by the upper electrodes and the lower electrodes, the welding cylinder respectively drives the upper electrodes to contact the welding points and the lower electrodes to weld the welding points respectively, so that the flatness of the metal mesh and the welding quality are ensured. The mesh welding machine disclosed by the invention has the advantages of low electricity consumption and energy conservation.

A composite resistance spot welding electrode is disclosed which comprises a co-axial annular neck ring, a co-axial insert, a co-axial annular sleeve, or combinations there of. The electrode provides improved nugget formation and longer electrode life.