Provided is a resistance spot welding method wherein main current passage includes two or more electrode force application steps including a first electrode force application step and a second electrode force application step following the first electrode force application step, an electrode force F.sub.1 in the first electrode force application step and an electrode force F.sub.2 in the second electrode force application step in the main current passage satisfy a relationship F.sub.1>F.sub.2, and an electrode force switching point T.sub.f from the first electrode force application step to the second electrode force application step in the main current passage is set to satisfy predetermined relational formulas.

A welding quality inspection apparatus for inspecting the welding quality of a plurality of welding parts formed on the material through the upper electrode and the lower electrode of the welding gun includes a position detection unit for detecting a position of the upper electrode, a control unit generating a position table based on a signal detected by the position detection unit during a total welding time of welding the plurality of welding parts of the material, generating first position data for a first welding time and second position data for a second welding time of a spot welding time of each of the welding parts based on the position table, checking whether the welding parts are defective by using the first position data, the second position data, and reference data, and generating result data based on whether the welding parts are detective, and an output unit for outputting the result data.

A resistance spot welding method comprises: performing test welding; and performing actual welding after the test welding. The test welding is performed under each of two or more welding conditions. In the actual welding, preliminary current passage is performed by constant current control in the same current pattern as in the preliminary current passage of the test welding, an electrical property between the electrodes in the preliminary current passage in the actual welding and an electrical property between the electrodes stored in the preliminary current passage in the test welding are compared for each welding condition to set a target in main current passage in the actual welding, and thereafter adaptive control welding is performed to control a current passage amount as the main current passage.

The present invention relates to methods and apparatus for detection of fire states in the presence of welding activities. In some examples, the welding detection system may algorithmically calculate a risk of a fire state developing. In some embodiments, the welding fire detection and prevention system may communicate warning states to users, supervisors, equipment and/or building monitoring systems.

A processing system according to an embodiment includes a processing device. The processing device receives a detection result of a reflected wave from a detector that includes multiple detection elements arranged in a first direction and a second direction crossing each other, and performs a probe that includes transmitting an ultrasonic wave toward a welding object and detecting the reflected wave. The processing device performs a first determination of determining a joint and a non-joint at multiple points along the first and second directions of the welding object based on the detection result. The processing device performs a second determination of determining an appropriateness of a result of the first determination by using a circularness of a first region based on the points determined to be joints.

The present invention relates micro resistance welding apparatus and to a method of welding. In particular, the present invention relates to small scale or micro welding apparatus and to a method of micro resistance welding using a controlled sequence of current, voltage and/or power signal profile for an electric arc. The invention provides a welding apparatus comprising: a controller supplying a controlled drive current to a weld head circuit in which the controller supplies said controlled drive current in dependence upon electrical feedback from the weld head circuit and in which the controlled drive current is defined by a sequence of segments and for each segment the welding apparatus operates in a mode defined by setting one of a predetermined current target, a predetermined voltage target or a predetermined power target; and at least two of the segments are operated in a different mode from one another. The invention also provide a method of operating such an apparatus.

A method for producing a resistance-welded member made of three or more sheets including a plated steel sheet includes: a main energizing by performing energization with a first current value while compressing the steel sheet with a first compressive force to form a nugget; a subsequent energizing by performing, after the main energizing, energization such that the current value gradually decreases from the first current value while compressing with a second compressive force greater than the first compressive force; and holding an electrode while maintaining the second compressive force after the subsequent energizing. The second compressive force and a total sheet thickness, compression rise delay time, and a downslope time and an electrode holding time satisfy respective predetermined conditions.

Resistance spot rivet welding systems, subsystems, and methods of use thereof are provided.

Resistance spot rivet welding systems, subsystems, and methods of use thereof are provided.

The disclosure concerns a method for monitoring and/or controlling a quality of spot weldings of a processing island, comprising at least two welding controls on one or more workpieces, wherein the method is based on a comparing of the measured values and an outputting of a fault message taking place from a central control of the processing island, the central control being in communicating connection with every welding control, in order to control them appropriately in dependence on all of the measured values and the predefined tolerance margin, the welding controls being in communicating connection with one another.