Patent ID: 11969813
Assignee: TOYOTA JIDOSHA KABUSHIKI KAISHA
Field: Machine tools (Mechanical engineering)
Classification: CPC B | IPC B

Claim 0:
1. A spot welding method comprising:
a heating step of providing input energy at a current value for energizing an electrode, the electrode in pressure contact with an aluminum alloy member to heat and melt a join part of the aluminum alloy member by resistance heating and the current value being a heating current value; and
a cooling step of cooling the join part after the heating step in a state in which the electrode is in pressure contact with the aluminum alloy member,
the aluminum alloy member being made of an aluminum alloy of Mg: 0.2 to 1.2 mass % (simply referred to as “%”), Si: 0.4 to 1.5%, and Cu: 1.1% or less or an aluminum alloy of Si: 7 to 11% and Mg: 0.1 to 0.4% with respect to 100% as a whole,
the cooling step including a first cooling process and a second cooling process,
wherein the first cooling process is performed immediately after the heating step and comprises gradually reducing the current value for energizing the electrode from the heating current value to a lower current value such that there is a reduced amount of input energy to the join part as compared with the heating step, and
wherein the second cooling process is performed after the first cooling process and the second cooling step is performed at a higher cooling rate than a cooling rate in the first cooling process, and
wherein when a temperature of a molten part formed in the heating step is cooled to within a temperature range (Ts+10° C. to Ts+50° C.) in which the temperature of the molten part is higher than a solidus temperature (Ts) of the aluminum alloy by 10 to 50° C., the cooling step is shifted from the first cooling process to the second cooling process.