An electrically conductive tip member includes: an inner periphery portion including a Cu matrix phase and a second phase that is dispersed in the Cu matrix phase and contains a Cu—Zr-based compound, the inner periphery portion having an alloy composition of Cu-xZr (where x is the atomic percentage of Zr and satisfies 0.5≤x≤16.7); and an outer periphery portion that is present on an outer circumferential side of the inner periphery portion, made of a metal containing Cu, and has higher electrical conductivity than the inner periphery portion.

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.

A Ni-based alloy core wire for a covered electrode according to an aspect of the invention includes, as a chemical composition, by mass %: C: 0.0100% to 0.0800%; Si: 0.010% to 0.800%; Mn: 0.010% to 1.800%; Mo: 15.0% to 28.0%; W: 2.5% to 8.0%; Cu: 0.10% to 1.20%; Ta: 0.002% to 0.120%; Ni: 65.0% to 82.3%; and a remainder: impurities with other optional selective elements; in which a value X is 0.010% to 0.160%.

The present disclosure is directed to flux-cored welding electrodes designed to produce higher toughness steel alloy weld deposits, and to the higher toughness weld deposits themselves. The weld deposits may comprise less than 0.20 (or less than 0.15) weight percent silicon. The flux-cored welding electrodes comprise a flux core and a tubular steel strip. The flux core may comprise, by weight percent of the electrode, 0.25-0.30% zirconium, 0.12-0.18% aluminum, and 0-0.11% silicon. The metallic zirconium, aluminum, and silicon may be added to the flux core in the form of silicon-zirconium metal powder and aluminum-zirconium metal powder.

A surface modification process and apparatus for the electro-spark deposition (ESD) on a workpiece may include mounting a workpiece on a rotationally driven mounting. The contact surface of the workpiece is ESD coated. Ultrasonic vibration is applied to the deposition layer during its crystallization phase. The workpiece may be a resistance spot welding electrode. The apparatus may have a vibrating applicator, ESD power supply, integrated ultrasonic transducer assembly, a work station having a rotational drive and an ultrasonic generator. The ultrasonic generator is connected to the ultrasonic transducer. The ultrasonic transducer assembly and the rotating driving work bench unit are integrated in a single assembly. The workpiece seats on the ultrasonic transducer assembly. The deposition of a surface coating occurs during simultaneous application of electro-spark deposition and ultrasonic vibration.

An electrode in which the metallurgical structure of the active surface includes incoherent chromium precipitates, more than 90% of which have a surface of projection of less than 1 m.sup.2, the incoherent chromium precipitates having a size at least between 10 and 50 nm. The electrode further has a fibrous structure that is visible in a cross-section of the active surface of the electrode following surfacing and chemical etching. The fibrous structure includes a plurality of radial fibers having a thickness of less than 1 mm and of a substantially central fiberless region that has a diameter of less than 3 mm. The electrical conductivity of the electrode is greater than 85% IUPAC. The method for obtaining the electrode in a continuous casting process as well as to a use of the electrode in a resistive spot welding process.

An electrically conductive tip member includes: an inner periphery portion including a Cu matrix phase and a second phase that is dispersed in the Cu matrix phase and contains a CuZr-based compound, the inner periphery portion having an alloy composition of Cu-xZr (where x is the atomic percentage of Zr and satisfies 0.5x16.7); and an outer periphery portion that is present on an outer circumferential side of the inner periphery portion, made of a metal containing Cu, and has higher electrical conductivity than the inner periphery portion.

A Ni-based alloy core wire for a covered electrode according to an aspect of the invention includes, as a chemical composition, by mass %: C: 0.0100% to 0.0800%; Si: 0.010% to 0.800%; Mn: 0.010% to 1.800%; Mo: 15.0% to 28.0%; W: 2.5% to 8.0%; Cu: 0.10% to 1.20%; Ta: 0.002% to 0.120%; Ni: 65.0% to 82.3%; and a remainder: impurities with other optional selective elements; in which a value X is 0.010% to 0.160%.

A transfer processing unit of a processing tool for an electrode for resistance spot welding that is configured to mold, through transfer processing, a projection portion and a plurality of recess portions at an electrode tip portion bulging into a projecting shape is provided with a plurality of protrusions that are configured to mold the plurality of the recess portions respectively. A virtual plane that links tips of the plurality of these protrusions with one another assumes a shape coinciding with a surface shape of the electrode tip portion bulging into the projecting shape before transfer processing.

An electrode in which the metallurgical structure of the active surface includes incoherent chromium precipitates, more than 90% of which have a surface of projection of less than 1 m.sup.2, the incoherent chromium precipitates having a size at least between 10 and 50 nm. The electrode further has a fibrous structure that is visible in a cross-section of the active surface of the electrode following surfacing and chemical etching. The fibrous structure includes a plurality of radial fibers having a thickness of less than 1 mm and of a substantially central fiberless region that has a diameter of less than 3 mm. The electrical conductivity of the electrode is greater than 85% IUPAC. The method for obtaining the electrode in a continuous casting process as well as to a use of the electrode in a resistive spot welding process.