A welding gun is incorporated into a unidirectional welding system, where the unidirectional welding system includes: the welding gun performing welding when a set pressing force is applied; a power portion configured to generate power to be applied to the welding gun; a power connecting portion having one end portion connected to the power portion through a power wire and an opposite end portion engaged with the welding gun; and a power switch provided at the power connecting portion to selectively apply the power generated from the power portion to the welding gun.

Provided is a spatter scattering prevention apparatus that eliminates the necessity to, for example, remove scattered spatters and thus makes it possible to facilitate maintenance work, and also provided is a flash butt welder including the spatter scattering prevention apparatus.

The spatter scattering prevention apparatus 1 according to the present invention is characterized by being configured to form a water screen in midair in the vicinity of a welding spot, at which welding is performed, wherein the water screen is for preventing spatters, generated during the welding, from scattering.

The spatter scattering prevention apparatus is also characterized by being configured to form the water screen on one side in a lateral direction of the welding spot and form the water screen on the other side, laterally opposite to the one side, of the welding spot.

Provided is a spatter scattering prevention apparatus that eliminates the necessity to, for example, remove scattered spatters and thus makes it possible to facilitate maintenance work, and also provided is a flash butt welder including the spatter scattering prevention apparatus.

The spatter scattering prevention apparatus 1 according to the present invention is characterized by being configured to form a water screen in midair in the vicinity of a welding spot, at which welding is performed, wherein the water screen is for preventing spatters, generated during the welding, from scattering.

The spatter scattering prevention apparatus is also characterized by being configured to form the water screen on one side in a lateral direction of the welding spot and form the water screen on the other side, laterally opposite to the one side, of the welding spot.

A method for checking quality when resistance-welding workpiece includes pressing welding electrodes with an electrode force against a weld spot of the workpieces using an electrode drive and energizing the welding electrodes with a welding current for a duration of a welding time in order to liquefy a surface of the workpieces. The method further includes determining, at a first time before a beginning of the liquefaction, a first value of a welding electrode parameter identifying a position of one or both electrodes, and determining, at a second time after the beginning of the liquefaction, a second value of the welding electrode parameter identifying a position of one or both electrodes. The method further includes comparing the first value and the second value and, evaluating a quality of the welding process based on the comparison.

A method of resistance spot welding and a spot-welded workpiece assembly are provided. First and second metallic workpieces are provided, each having faying surfaces including interface portions. The workpieces are disposed with the interface portions of their faying interfaces spaced apart from each other by a predetermined spacing distance. A set of opposed welding electrodes including a first electrode and a second electrode are provided, the first electrode being disposed on a side of the first workpiece, and the second electrode being disposed on a side of the second workpiece. Pressure is applied to the workpieces via the weld faces of the electrodes, and the workpieces are heated via the electrodes to form a spot weld joint between the interfaces of the faying surfaces. The faying surfaces may be spaced apart with shim material, a raised or folded-over portion of a workpiece, and/or a filler material having spacing particles.

A method of resistance spot welding and a spot-welded workpiece assembly are provided. First and second metallic workpieces are provided, each having faying surfaces including interface portions. The workpieces are disposed with the interface portions of their faying interfaces spaced apart from each other by a predetermined spacing distance. A set of opposed welding electrodes including a first electrode and a second electrode are provided, the first electrode being disposed on a side of the first workpiece, and the second electrode being disposed on a side of the second workpiece. Pressure is applied to the workpieces via the weld faces of the electrodes, and the workpieces are heated via the electrodes to form a spot weld joint between the interfaces of the faying surfaces. The faying surfaces may be spaced apart with shim material, a raised or folded-over portion of a workpiece, and/or a filler material having spacing particles.

To provide a method and apparatus for manufacturing a joined member that inhibit occurrence of cracks in a joined member even when the joined portion is quenched when members are welded together. The method includes placing the first member D and the second member E with a joint target portion Df and a joint target portion Ef being in contact with each other, welding the joint target portions by heating, subjecting the first member D after the welding to a process for inhibiting occurrence of cracks, and tempering a portion where the first and second members have been welded to each other by electromagnetic heating. The apparatus includes a first electrode 11 to contact with the first member D; a second electrode 12 to contact with the second member E; and an induction heating coil 23 for performing induction heating of a portion where a joint target portions Df and Ef have been contacted and joined to each other, and the induction heating coil 23 is placed between the two electrodes 11 and 12 when the induction heating is performed.

To provide a method and apparatus for manufacturing a joined member that inhibit occurrence of cracks in a joined member even when the joined portion is quenched when members are welded together. The method includes placing the first member D and the second member E with a joint target portion Df and a joint target portion Ef being in contact with each other, welding the joint target portions by heating, subjecting the first member D after the welding to a process for inhibiting occurrence of cracks, and tempering a portion where the first and second members have been welded to each other by electromagnetic heating. The apparatus includes a first electrode 11 to contact with the first member D; a second electrode 12 to contact with the second member E; and an induction heating coil 23 for performing induction heating of a portion where a joint target portions Df and Ef have been contacted and joined to each other, and the induction heating coil 23 is placed between the two electrodes 11 and 12 when the induction heating is performed.

A welding gun includes a proximity restricting mechanism that is provided between a shaft and a cover member in a manner to surround the shaft and to be displaceable relative to the shaft in an axial direction in accordance with expansion and contraction of the cover member, and that restricts the cover member from approaching too closely the shaft.

A welding gun includes a proximity restricting mechanism that is provided between a shaft and a cover member in a manner to surround the shaft and to be displaceable relative to the shaft in an axial direction in accordance with expansion and contraction of the cover member, and that restricts the cover member from approaching too closely the shaft.