A capacitive discharge welding system includes at least one capacitive discharge-based power supply that is adapted to provide alternate polarity pulses from a first weld to a subsequent weld, and to be compatible with iron-core transformers used for alternating current resistance welding; at least one iron core transformer adapted to receive electrical discharges from the capacitive discharge-based power supply; a polarity switching network that includes at least two sets of silicon controlled rectifiers that are arranged in pairs for facilitating current flow in alternate directions; a pair of engagable, properly biased shunt diodes that are operative to shunt reflected current for protecting the silicon controlled rectifiers when the system is in use; and a control network configured for simultaneous engagement of the properly biased shunt diodes and firing the silicon controlled rectifiers for current flow; and tracking polarity for assuring that subsequent pulses use opposite direction current flow for preventing saturation of the iron core transformer.

A method of joining parts, where at least one of the parts has a faying surface defining grooves therein. One of the parts is formed of a majority of titanium, and the other part is formed of a majority of iron. The method includes providing a set of opposed welding electrodes disposed on a side of each part and applying pressure to and heating the parts via the set of electrodes to form a joint between the parts. A bonded assembly includes a first part formed of a majority of titanium and a second part formed of a steel alloy. The first and second parts having a bond that includes a portion of the first part directly in contact with and attached to a portion of the second part. The parts may be a titanium-containing differential carrier case bonded to a steel gear.

A method of joining parts, where at least one of the parts has a faying surface defining grooves therein. One of the parts is formed of a majority of titanium, and the other part is formed of a majority of iron. The method includes providing a set of opposed welding electrodes disposed on a side of each part and applying pressure to and heating the parts via the set of electrodes to form a joint between the parts. A bonded assembly includes a first part formed of a majority of titanium and a second part formed of a steel alloy. The first and second parts having a bond that includes a portion of the first part directly in contact with and attached to a portion of the second part. The parts may be a titanium-containing differential carrier case bonded to a steel gear.

A high-pressure fuel pump for a fuel injection system of an internal combustion engine includes a pump housing and at least one fastening flange that is fixed to the pump housing by a welding. The welding has one weld region and at least one weld bead arranged laterally from the weld region. The weld bead is arranged in a receiving space formed between the pump housing and the fastening flange.

A portable stud welder apparatus is provided for welding a stud onto a work piece. The portable stud welder apparatus includes a housing and an energy storage device. A weld stud gun that is configured to hold a weld stud is electrically connected to the energy storage device for receiving energy from the energy storage device to pass a current through the stud and the work piece to form a weldment. At least one battery of the lithium ion type that is removeably coupled to the housing to establish an electrical connection with said energy storage device and provide energy to the energy storage device.

A portable stud welder apparatus is provided for welding a stud onto a work piece. The portable stud welder apparatus includes a housing and an energy storage device. A weld stud gun that is configured to hold a weld stud is electrically connected to the energy storage device for receiving energy from the energy storage device to pass a current through the stud and the work piece to form a weldment. At least one battery of the lithium ion type that is removeably coupled to the housing to establish an electrical connection with said energy storage device and provide energy to the energy storage device.

A method of resistance welding first and second parts formed of dissimilar materials includes disposing a first electrode on a side of the first part and a second electrode on a side of the second part. Grooves separated by raised portions are formed in a faying surface of the second part. Pressure is applied to the first and second parts via the set of electrodes, and the parts are heated via the electrodes to form a joint between the parts. A welded assembly includes metallic first and second parts welded together. The second part may have a faying surface defining a number of grooves separated by raised portions. The faying surfaces of the parts may be disposed at 10-80 degree angles with respect to a first part axis (and/or a welding pressure axis).

A torque converter includes a cover having a first surface and an annular plate axially spaced from the cover and having a second surface facing the first surface. A disc of the torque converter is disposed between the cover and the plate and has opposing first and second faces adjacent to the first and second surfaces, respectfully. Each of the faces defines a projection joined to one of the first and second surfaces by at least one capacitive discharge weld.

A direct resistance heating simulation method is provided. In this method, a welding region and its peripheral region of steel sheets to be welded by a pair of electrodes are divided into a plurality of elements. A coupled analysis is performed such that a temperature, a metal structure, stress and strain at each element are determine in a mutually associated manner based on Joule loss obtained through a current analysis and a magnetic field analysis for each element. The coupled analysis is repeated to predict an effect of one or more parameters, including at least one of a frequency, a magnitude and an application time of electric current to be applied to the electrodes, a cooling time, a pressure applied from the electrodes to the steel sheets and a shape of the electrodes, on welding quality after a post-heating by direct resistance heating and to improve weld strength.

A direct resistance heating simulation method is provided. In this method, a welding region and its peripheral region of steel sheets to be welded by a pair of electrodes are divided into a plurality of elements. A coupled analysis is performed such that a temperature, a metal structure, stress and strain at each element are determine in a mutually associated manner based on Joule loss obtained through a current analysis and a magnetic field analysis for each element. The coupled analysis is repeated to predict an effect of one or more parameters, including at least one of a frequency, a magnitude and an application time of electric current to be applied to the electrodes, a cooling time, a pressure applied from the electrodes to the steel sheets and a shape of the electrodes, on welding quality after a post-heating by direct resistance heating and to improve weld strength.