Abstract: A spot welding method and a spot welding apparatus are provided. A stacked assembly of at least three workpieces is gripped between first and second welding tips. An inner workpiece positioned inside of the stacked assembly, of two of the workpieces that exhibit a maximum contact resistance in the stacked assembly, is electrically connected to a ground electrode, or to an electrode having the same polarity as the second welding tip near an outer workpiece positioned adjacent to the inner workpiece and facing outwardly from the stacked assembly, of the two workpieces. Then, electric current is applied from the first welding tip toward the second welding tip. In this case, first, the stacked assembly is pressed under a first pressing force, and then, the stacked assembly is pressed under a second pressing force which is greater than the first pressing force.

Abstract: A one-side spot welding method for causing an electrode to contact a welding portion of a work-piece only from one side of the work-piece to weld the work-piece, the method includes a nugget forming process of applying welding pressure to the work-piece through the electrode, and causing the work-piece to be fully electrically conducted at a predetermined current value, and a slow-cooling process of applying welding pressure to the work-piece through the electrode from the one side, and causing the work-piece to be electrically conducted at a current value lower than the predetermined current value after the nugget forming process.

Abstract: Provided is a method for producing a zinc alloy capable of obtaining a Zn—Si alloy having a uniform composition. Metal Zn is melted in a crucible (2) provided in a heating furnace (1) to obtain a Zn molten metal (4). Floating of a metal Si powder (6) added to the Zn molten metal (4) is suppressed by a floating suppressing member (5). Heating is performed while a liquid surface of the Zn molten metal (4) is coated with a carbonaceous material (9), thereby melting the metal Si powder (6). The suppression of the floating of the metal Si powder (6) is released to allow the melted Si to be dispersed in the Zn molten metal (4), thereby obtaining a Zn—Si alloy molten metal (11). A copper casting mold (12) is filled with the Zn—Si alloy molten metal (11), and is rapidly cooled down to obtain a billet.

Abstract: Provided is an arc welding method and arc welding apparatus for arc welding by a brazing filler metal two base materials subjected to a plating process. An arc welding method for arc welding two base materials, at least one of which has a plating layer thereon, by a brazing filler material, performs alternately a plating layer removal process of removing a plating layer by performing arc discharge at a first current value while moving a welding torch along a welding line in a state of stopping feed of the brazing filler metal, and a brazing filler metal welding process of welding the brazing filler metal to a position where the plating layer is removed, by performing arc discharge at a second current value smaller than the first current value while feeding the brazing filler metal in a state of stopping a movement of the welding torch.

Abstract: Provided is a method for producing a zinc alloy capable of obtaining a Zn—Si alloy having a uniform composition. Metal Zn is melted in a crucible (2) provided in a heating furnace (1) to obtain a Zn molten metal (4). Floating of a metal Si powder (6) added to the Zn molten metal (4) is suppressed by a floating suppressing member (5). Heating is performed while a liquid surface of the Zn molten metal (4) is coated with a carbonaceous material (9), thereby melting the metal Si powder (6). The suppression of the floating of the metal Si powder (6) is released to allow the melted Si to be dispersed in the Zn molten metal (4), thereby obtaining a Zn—Si alloy molten metal (11). A copper casting mold (12) is filled with the Zn—Si alloy molten metal (11), and is rapidly cooled down to obtain a billet.

Abstract: Provided is an arc welding method and arc welding apparatus for arc welding by a brazing filler metal two base materials subjected to a plating process. An arc welding method for arc welding two base materials, at least one of which has a plating layer thereon, by a brazing filler material, performs alternately a plating layer removal process of removing a plating layer by performing arc discharge at a first current value while moving a welding torch along a welding line in a state of stopping feed of the brazing filler metal, and a brazing filler metal welding process of welding the brazing filler metal to a position where the plating layer is removed, by performing arc discharge at a second current value smaller than the first current value while feeding the brazing filler metal in a state of stopping a movement of the welding torch.

Abstract: A one-side spot welding method for causing an electrode to contact a welding portion of a work-piece only from one side of the work-piece to weld the work-piece, the method includes a nugget forming process of applying welding pressure to the work-piece through the electrode, and causing the work-piece to be fully electrically conducted at a predetermined current value, and a slow-cooling process of applying welding pressure to the work-piece through the electrode from the one side, and causing the work-piece to be electrically conducted at a current value lower than the predetermined current value after the nugget forming process.

Abstract: A spot welding method and a spot welding apparatus are provided. A stacked assembly of at least three workpieces is gripped between first and second welding tips. An inner workpiece positioned inside of the stacked assembly, of two of the workpieces that exhibit a maximum contact resistance in the stacked assembly, is electrically connected to a ground electrode, or to an electrode having the same polarity as the second welding tip near an outer workpiece positioned adjacent to the inner workpiece and facing outwardly from the stacked assembly, of the two workpieces. Then, electric current is applied from the first welding tip toward the second welding tip. In this case, first, the stacked assembly is pressed under a first pressing force, and then, the stacked assembly is pressed under a second pressing force which is greater than the first pressing force.