Spatter detection method and method for manufacturing welded member
A spatter detection method in which the accuracy of detection of an occurrence of sputter is high, and a method for manufacturing a welded member are provided. A spatter detection method according to the present disclosure is a spatter detection method for detecting an occurrence of sputter in resistance spot welding, the resistance spot welding being welding in which a material to be welded, obtained by stacking a plurality of metal members on one another, is joined by sandwiching the material to be welded between a pair of electrodes and feeding an electric current therethrough, in which the occurrence of sputter is detected based on a change in a volume of a molten part of the material to be welded.
1 . A spatter detection method for detecting an occurrence of sputter in resistance spot welding, the resistance spot welding being welding in which a material to be welded, obtained by stacking a plurality of metal members on one another, is joined by sandwiching the material to be welded between a pair of electrodes and feeding an electric current therethrough, wherein
the occurrence of sputter is detected based on a change in a volume of a molten part of the material to be welded, wherein
the pair of electrodes comprises a first electrode, and a second electrode movable relative to the first electrode in a direction in which the metal members are stacked on one another, and
the change in the volume of the molten part is calculated based on a change in a distance between the first and second electrodes, and a change in an internal stress of the molten part.
2 . The spatter detection method according to claim 1 , wherein the sputter is detected based on a rate of change at which the volume of the molten part decreases.
3 . The spatter detection method according to claim 1 , wherein the change in the volume of the molten part is calculated by Expression (1),
E=S+a×F (1)
where E is the change in the volume of the molten part; S is a stroke of the second electrode; a is a distortion conversion coefficient; and F is a pressure between the first and second electrodes.