In a resistance spot welding method, test welding and actual welding in which a current pattern is divided into two or more steps are performed. In the test welding, a constant current of a different value is passed in each step, and a time variation of an instantaneous amount of heat generated per unit volume and a cumulative amount of heat generated per unit volume are stored as a target value. In the subsequent actual welding, when a time variation amount of an instantaneous amount of heat generated per unit volume deviates during any step from the results of the test welding, a current passage amount is controlled to compensate for the difference during a remaining welding time in the step. In the test welding, 0.3×I.sub.x≦I.sub.a<I.sub.x, where I.sub.a is the current in the first step, and I.sub.x is the current in second and subsequent steps.

A gas diffusion electrode for a membrane electrode assembly is provided with expanded metal layers each having a mesh configuration defining a length orientation of the expanded metal layers. The expanded metal layers each have opposed flat sides and are stacked in a layered arrangement such that the flat sides of the expanded metal layers that are neighboring each other in the layered arrangement are facing each other as facing flat sides, respectively. The facing flat sides are connected to each other by pulsed resistance welding at welded contact points. Due to the mesh configuration, the welded contact points are distributed evenly across the entire surface area of the facing flat sides. At least one of the expanded metal layers is oriented with its length orientation so as to be rotated by 90° relative to the length orientation of one of the neighboring expanded metal layers.

The present disclosure provides a welding electrode and methods of manufacturing the same. The welding electrode can include a composite body having a tip portion and an end portion. The composite body can include a shell defining a cavity through the end portion, the shell comprising a first metal that includes one or more of the following: a precipitation hardened copper alloy, copper alloy, and carbon steel. The composite body can also include a core within the shell, the core extending through the shell from the tip portion to the cavity, the core comprising a second metal that includes dispersion strengthened copper. The core and the shell have a metallurgical bond formed from co-extrusion.

The present disclosure provides a method of manufacturing a composite material. The method can include compacting a copper alloy powder into a plurality of substantially uniform compressed sub-assemblies such that the copper alloy powder has a density that is greater than 50%. The plurality of compressed sub-assemblies can be layered relative one another within an aperture of a shell, the plurality of compressed sub-assemblies to form a consecutive assembly of compacted copper alloy. The shell may include one of the following: a precipitation hardened copper alloy, copper alloy, and carbon steel. The consecutive assembly can be sealed within the shell to form a billet. The billet can be hot-extruded to form a rod, and the extruded rod can be further drawn to form a composite wire of a desired diameter. The composite wire may be used to create a composite welding electrode.

A guide hole is constituted of a large-diameter hole, a medium-diameter hole, and a small-diameter hole. A sliding part fitted in the guide hole is formed of a synthetic resin material. A large-diameter portion of the sliding part is fitted in the large-diameter hole in a slidable state, and a medium-diameter portion is fitted in the medium-diameter hole in a slidable state. A movable end surface of the sliding part is in close contact with a stationary inner end surface of the guide hole. By configuring a width dimension of the movable end surface to be less than half of a thickness dimension of the large-diameter portion, a pressurizing force of the movable end surface is increased and a minute metal piece is pushed from the movable end surface into a base material of the sliding part, and a thickness dimension of the medium-diameter portion is set large.

Embodiments of the present invention include a plasma cutting torch and plasma cutting torch components, such as electrodes, cathodes, retainer caps, etc. having a unique physical features, including threads relationships. Embodiments include torch components having modified square thread with a specialized thread configuration including a particular relationship between thread crest and root, and included angles of thread sidewalls.

The present disclosure is directed to an electronic component mounting structure including: a circuit board provided on a surface thereof with a first electrode containing Cu as a main component; and an electronic component mounted on the circuit board, the electronic component including a second electrode on a surface thereof; wherein the second electrode includes a first plating containing Ni as a main component and a second plating containing Sn as a main component formed on a surface of the first plating, and an intermediate bonding layer is provided between the first plating and the first electrode, and the intermediate bonding layer includes a first region containing an alloy of Cu and Sn as a main component and a second region containing Sn as a main component.

A method for manufacturing a soldered product by soldering a solder object portion, including: a solder supplying step that causes a cylindrical soldering iron having a through hole to contact with the solder object portion to supply a thread solder piece to the solder object portion from the through hole; a heating step that heats the thread solder piece with the cylindrical soldering iron and causes to melt the thread solder piece at the solder object portion; and a curing step that cures a melting object of the thread solder piece to solder the solder object portion. The thread solder piece is composed of a core containing a flux and a coating member containing a solder alloy that covers the core. The flux has a rosin having an acid value which is substantially as a main component thereof.

A welding electrode for use in resistance spot welding an assembly of metal workpieces with curved surfaces and closed or open sections is disclosed. The welding electrode includes a body, a weld face at one end of the body, and contoured curvature forming the weld face. The contoured curvature is configured to seat around the curved surfaces of the metal workpieces when the weld face is pressed against the workpieces during a resistance spot weld event. When brought into contact with the curved surface of the workpiece, the electrode has an optimal contact area, which improves the spot weld process by improving the pressure and current distributions.

An electrode tip portion is provided with a projection portion and a plurality of recess portions. The plurality of the recess portions are independent of one another, and are provided at the electrode tip portion in a dispersed manner. The projection portion is a region other than regions where the recess portions are provided, and is configured to be equipped with a continuous surface that continues in regions among the plurality of the recess portions.