| 摘要 |
PROBLEM TO BE SOLVED: To provide a joined structure of steel/aluminum in which the formation of a brittle Al-Fe binary alloy layer on the joining boundary after cooling is suppressed in a metal inert gas welding to improve a joining strength. SOLUTION: The joined structure is obtained by subjecting a hot dip aluminum plated steel sheet 1 in which a hot dip aluminum plating layer 4 is formed on the surface of a base steel sheet 5 to lap fillet welding with an aluminum or aluminum alloy material 2 by metal inert gas welding. The hot dip aluminum plating layer 4 has a composition containing, by mass, 3 to 12% Si, 0.5 to 5% Fe, and the balance Al with inevitable impurities. Further, the area ratio of an Al-Fe binary alloy layer 7 occupying in the joining boundary between the steel sheet and the weld metal zone is≤95%, and an alloy layer-dissipated region 9 is present between an Al-Fe-Si ternary alloy layer 6 produced on the grain boundary between the base steel sheet 5 and the aluminum plating layer 4 and an Fe-Al binary alloy layer 7 on the joining boundary. COPYRIGHT: (C)2008,JPO&INPIT |
