Provided is a method of welding laminated metal foils that can prevent blowholes and spatter from being formed. It is a method of welding laminated metal foils sandwiched between a pair of metal plates to the pair of metal plates. The method of welding laminated metal foils sandwiched between a pair of metal plates to the pair of metal plates includes locally pressing and crimping the laminated metal foils sandwiched between the pair of metal plates at a welding point in a laminating direction, and welding the crimped pair of metal plates and laminated metal foils at the welding point.

A joining system (100) of the present invention is for joining a joining target (W) including first, second, and third members (W1), (W2), (W3), and includes a welder (101), a friction stir welding machine (102), and a controller (110) that: (A) causes the welder (101) to weld the second and third members (W2), (W3); (B), after (A), causes the joining target (W) to be placed at the friction stir welding machine (102) so that the first member (W1) is opposed to a distal end of a tool (10); and (C), after (B), controls a linear motion driver (7) and a rotation driver (8) so as to, while pressing the distal end of the tool (10) to the joining target (W), rotate the tool (10) around an axis, so that the softened second and third members (W2), (W3) intrude into the softened first member (W1), thus joining the joining target (W).

A joining system (100) of the present invention is for joining a joining target (W) including first, second, and third members (W1), (W2), (W3), and includes a welder (101), a friction stir welding machine (102), and a controller (110) that: (A) causes the welder (101) to weld the second and third members (W2), (W3); (B), after (A), causes the joining target (W) to be placed at the friction stir welding machine (102) so that the first member (W1) is opposed to a distal end of a tool (10); and (C), after (B), controls a linear motion driver (7) and a rotation driver (8) so as to, while pressing the distal end of the tool (10) to the joining target (W), rotate the tool (10) around an axis, so that the softened second and third members (W2), (W3) intrude into the softened first member (W1), thus joining the joining target (W).

The present invention relates to a direct-contact type alternating current (AC) trapezoidal wave aluminum resistance welding process method. AC trapezoidal wave inverter controller capable of controlling a positive and negative half-wave current rising rate, and an AC transformer (no rectifier or silicon-controlled rectifier on a secondary coil of the transformer) with an output voltage of 10-30V, a peak current of 32-70 kiloampere and a frequency of 25-80 Hz are included. The inverter controller and the AC transformer are connected by means of a conductor, a welding electrode, a pressurization mechanism and a cooling system to form resistance welding equipment to enable the equipment to output positive and negative alternating trapezoidal wave current on two sides of the electrode when a workpiece is pressurized and welded and to perform welding according to a specified duty ratio, welding current, frequencies, welding cycle number and welding pressure. Practice proves that the method has the advantages that 50-150 welding spots can be welded while grinding the electrode once each time, service life of the electrode is prolonged by 2-5 times, production efficiency and welding quality are greatly improved, and production cost is reduced, thereby realizing a qualitative leap in aluminum and aluminum alloy resistance welding processes.

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.

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.

A welding electrode for an electric resistance welding process. The welding electrode includes a body extending along a center axis and terminating axially at a weld face for contacting a work face. The weld face defines a center along the axis and defines an outer edge spaced radially from the center. A plurality of senates are defined along the weld face. Each of the serrates projects axially away from the weld face and extends radially from the center axis to the outer edge of the weld face. A higher density of the plurality of serrates is formed proximate to the center axis than proximate to the outer circumference of the weld face. Methods for using the welding electrode and forming the senates on the welding electrode are also provided.

A method for bonding electrical conductors is provided that is capable of suppressing a power source capacity when assembling a stator having a specific structure. First, coil pieces 9 are arranged in contact with bonding portions of a slot coil 5 inserted in a slot of a stator iron core 2 via a metal paste. Subsequently, an electrical current is applied using a pair of electrodes 11A and 11B in the axial direction (upward and downward in the figures) of the slot coil 5 while contact portions 15 between the slot coil 5 and the coil pieces 9 are pressed in an axial direction of the slot coil 5. As a result, electricity flows in the axial direction the coil piece 9 (a direction of an arrow X in the figures).

Aluminum-base alloy workpieces have surfaces with films of aluminum oxide which inhibit good contact with weld faces of resistance spot weld electrodes and the faying surfaces of, for example, sheet workpieces stacked for welding. Sometimes, the surfaces of the sheets also are coated with an adhesive or a sealer which further complicates welding. But in accordance with this invention, weld faces of opposing, round, copper welding electrodes are pressed against opposite outside surfaces of the sheets at a spot weld site and weld current is applied to the electrodes in accordance with a three-stage weld schedule to better form each weld. The weld schedule comprises a Conditioning stage (stage 1), a weld nugget Shaping stage (stage 2), and a weld nugget Sizing stage (stage 3).

A mass flow controller and mass flow meter are disclosed. The mass flow controller and mass flow meter include a sensor tube configured to transport a fluid, and an upstream heater element and a downstream heater element which are formed of heating resistance wires provided in an outer periphery of the sensor tube. At least one weld terminal is electrically connected to an end of one or more of the heating resistance wires by spot welding material. A temperature difference between the melting point of the weld terminal and a melting point of the heating resistance wires does not exceed 100 degrees Celsius, and one or more coat layer(s) is provided on a surface of the weld terminal.