DLA Piper LLP (US)
Resistance spot welding method and welded member production method
A resistance spot welding method inhibits, in accordance with the electrode angle, the occurrence of cracking in the weld regardless of the steel grade. The resistance spot welding method satisfies relationships: 2·A·(t·T/F)1/2≤H when 0≤A<1(3·A−1)·(t·T/F)1/2≤H when 1≤A<10(A+19)·(t·T/F)1/2≤H when 10≤A<20 where H (ms) is an electrode force retaining time after completion of current passage, A (degrees) is an electrode angle of the electrodes, t (mm) is a sheet thickness of a steel sheet having a largest sheet thickness among the steel sheets, T (MPa) is a tensile strength of a steel sheet having a highest tensile strength among the two or more steel sheets, and F (N) is the electrode force. 
JFE Steel Corporation
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B23K B23K B23K B23K B23K
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Koichi Chikaumi Rinsei Hiroshi Katsutoshi
Taniguchi Sawanishi Ikeda Matsuda Takashima