A resistance spot welding method comprises: performing test welding; and performing actual welding after the test welding, wherein the test welding is performed under each of two or more welding conditions. In the test welding, for each of the welding conditions, an electrode force parameter from when electrode force application to parts to be welded starts to when a set electrode force is reached before start of current passage and a time variation curve of an instantaneous amount of heat generated and a cumulative amount of heat generated are stored. In the actual welding: electrode force application to the parts to be welded is performed under each of the same conditions as in the test welding before start of current passage, and a corresponding electrode force parameter and the parameter stored in the test welding are compared for each of the welding conditions to set a target of a time variation curve of an instantaneous amount of heat generated and a cumulative amount of heat generated in the actual welding; and adaptive control welding is performed to control a current passage amount according to the target.

The present disclosure generally relates to a welding machine adapted for performing a spot welding process on a workpiece, wherein the welding machine is specifically adapted for automatically applying pre-conditioning a welding pulse portion to the workpiece prior to performing the spot welding process. The present disclosure also relates to a corresponding method and computer program product.

The present disclosure generally relates to a welding machine adapted for performing a spot welding process on a workpiece, wherein the welding machine is specifically adapted for automatically applying pre-conditioning a welding pulse portion to the workpiece prior to performing the spot welding process. The present disclosure also relates to a corresponding method and computer program product.

A resistance spot welding method comprises: performing test welding; and performing actual welding after the test welding, wherein in the test welding, 0.2Vtp/Vtm1.5 is satisfied where Vtm is an average value of a voltage between the electrodes in main current passage in the test welding and Vtp is an average value of a voltage between the electrodes in subsequent current passage in the test welding, and in each of main current passage and subsequent current passage in the actual welding, a time variation curve of an instantaneous amount of heat generated per unit volume and a cumulative amount of heat generated per unit volume that are stored in a corresponding one of the main current passage and the subsequent current passage in the test welding are set as a target, and adaptive control welding is performed to control a current passage amount according to the target.

A sensor element includes: an element body including, for example, a thermistor; paired lead wires drawn out from the element body; and stranded wires that are each obtained by twisting a plurality of core wires and are joined to the respective paired lead wires in a welding region. The welding region includes a main joining region provided in a predetermined region in an axis direction, and sub joining regions adjacent to the main joining region, and joining strength of each of the lead wires and the corresponding stranded wire is higher in the main joining region than in the sub-joining region.

The disclosure relates to a power component for providing an electric current, having plates aligned parallel to one another which are connected to the current inputs and the current outputs of power semiconductors embedded in a component carrier. High currents, for example for resistance welding, can thereby be controlled without excessive heat losses resulting in an increase in temperature of the entire arrangement and thereby in a reduction of the service life.

A resistance spot welding method of squeezing parts to be welded, which are a plurality of overlapping metal sheets, by a pair of electrodes and passing a current while applying an electrode force to join the parts to be welded comprises: a first step of passing a current by constant current control to form a fusion zone having a diameter of not less than 2t, expressed in mm, between the metal sheets, where t, expressed in mm, is a sheet thickness of a thinnest metal sheet of the metal sheets; a second step of cooling the fusion zone to have a diameter of not greater than 80% of D, where D, expressed in mm, is a diameter of the fusion zone formed in the first step; and a third step of performing adaptive control welding by controlling a current passage amount according to a target that is set.

A resistance spot welding method of squeezing parts to be welded, which are a plurality of overlapping metal sheets, by a pair of electrodes and passing a current while applying an electrode force to join the parts to be welded comprises: a first step of passing a current by constant current control to form a fusion zone having a diameter of not less than 2t, expressed in mm, between the metal sheets, where t, expressed in mm, is a sheet thickness of a thinnest metal sheet of the metal sheets; a second step of cooling the fusion zone to have a diameter of not greater than 80% of D, where D, expressed in mm, is a diameter of the fusion zone formed in the first step; and a third step of performing adaptive control welding by controlling a current passage amount according to a target that is set.

A data transmission method for a resistance welding current source during a welding operation generates welding pulses in an inverter with inverter switching elements cyclically with a switching frequency and pulse duration. The pulses are applied to a transformer primary side and rectified on the transformer secondary side by a rectifier with rectifier switching elements to form a resultant welding current. In a data transmission mode the impedance at the primary side is increased in the breaks in the welding operation, control pulses for initializing the data transmission mode are applied by a control device to the primary side and are detected on the secondary side. The rectifier switching elements of the secondary-side rectifier are actuated in a way corresponding to the data to be transmitted. The current on the primary side of the transformer is modulated with these data, and the data are thereby transmitted via the transformer.

A resistance spot welded joint according to an aspect of the present invention includes: a plurality of overlapping steel sheets; and a weld having a nugget by which the steel sheets are joined, and having a corona bond and a heat-affected zone formed around the nugget, in which one or more of the plurality of steel sheets are high strength steel sheets having a tensile strength of 780 MPa or more, one or more of the plurality of steel sheets are plated steel sheets having a zinc-based plating, the high strength steel sheet and the zinc-based plating are adjacent to each other on a contact surface, a diameter of the heat-affected zone is 1.5 times or more a diameter of the nugget, in the heat-affected zone, carbides having a circle equivalent diameter of 0.1 or more are distributed at a number density of 40/100 ?m.sup.2 or more, and in the corona bond, an amount of an ? phase of the zinc-based plating is 20 area % or less.