Resistance spot welding method

A resistance spot welding method for joining a sheet set including a plurality of lapped steel sheets, the method comprising:

• holding the sheet set between a pair of electrodes;
• and energizing the sheet set under application of electrode force to thereby join the steel sheets together,
• wherein at least one of the plurality of lapped steel sheets is a surface-treated steel sheet including a metal coating layer on a surface thereof,
• wherein the energizing comprises
• a primary energizing step of performing energization to form a nugget portion,
• a non-energizing step in which, after the primary energizing step, the energization is suspended for an energization suspension time Tc (cycles), and
• a secondary energizing step of, after the non-energizing step, performing energization for reheating while the nugget portion is prevented from growing, and
• wherein, during the energizing, the relations of the following formula (I) are satisfied:
• (22+A)·B/100<Ip/Im<C when 0<A<3,
• (17+A)·B/80<Ip/Im<C when 3≤A<7, and
• (11+A)·B/60<Ip/Im<C when 7≤A<15, formula (I)
• where A is an electrode misalignment angle (degrees) of the electrodes, Im is a current value (kA) in the primary energizing step, Ip is a current value (kA) in the secondary energizing step, B is a variable defined as 1+0.1·Tc, and C is a variable defined as 1+0.2·Tc.