LAP SPOT WELDING METHOD FOR MULTILAYER METAL PLATE

摘要

PROBLEM TO BE SOLVED: To provide a lap spot welding method for a multilayer metal plate that is used for improving efficiency in welding and improving quality of a nugget in a conventional resistance spot welding technique.SOLUTION: The lap spot welding method for a multilayer metal plate performs the steps of: forming a welding work area by applying an activator with high resistivity to a site to be jointed between any two adjacent metal plates to coat the surfaces of the metal plates; and holding the welding work area by an upper electrode and a lower electrode in cooperation, further passing an electric current to the welding work area, and melting the site at which the adjacent two metal plates are jointed by high heat of resistance generated by the activator with high resistivity to be jointed. The resistivity of the activator with high resistivity is far higher than the resistivity of the metal plates, and the activator with high resistivity is composed by mixing multi-composition powder with an organic solvent.