| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a method of joining dissimilar metals of magnesium alloy and steel by resistant spot welding which enables strong joining even when a combination of the magnesium alloy and the steel which indicates a two phase separation type i an Fe-Mg binary phase diagram so that direct joining is metallurgically difficult. <P>SOLUTION: When a magnesium alloy material and a steel material are joined by the resistant spot welding, a galvanized steel sheet 1 having as a third material a plating layer 1c containing zinc causing eutectic fusion with Mg and the magnesium alloy material 1 containing Al are used. Electrical heating and pressurization are carried out using an electrode having a curved surface of a tip end with a radius R of a curvature corresponding to the thickness (t) of the magnesium alloy material 1, so that the eutectic fusion of the Mg and Zn is caused and an oxidation film 2f and impurities are discharged from a joining interface as an exhaust material W. An intermetallic compound with the Al is generated at a joining surface and both materials 1, 2 are joined through a chemical compound layer 3 containing Al-Mg-based or Fe-Al-based intermetallic compounds. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
