The present disclosure inhibits liquid metal embrittlement (LME) cracking and improves corrosion resistance in a welded joint obtained by spot welding a first steel sheet and a second steel sheet. In the welded joint of the present disclosure, a first plating layer is provided on a surface of the first steel sheet facing the second steel sheet, no plating layer is present on or a second plating layer is provided on a surface of the second steel sheet facing the first steel sheet, and a boundary plating layer is provided between the first steel sheet and the second steel sheet in a range of 0.5 mm from an end part of the corona bond toward an outside of the spot welded part. A higher tensile strength of a tensile strength of the first steel sheet and a tensile strength of the second steel sheet is 780 MPa or more, an area ratio of a MgZn2 phase at the cross-section of the boundary plating layer is 10% or more, and the first plating layer and the second plating layer satisfy a predetermined Relation I.
WELDED JOINT AND AUTOMOBILE MEMBER
2024-03-21
Patent
Electronic Resource
English
IPC: | F16B DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES , Vorrichtungen zum Befestigen oder Sichern von Konstruktionselementen oder Maschinenteilen, z.B. Nägel, Bolzen, Schrauben, Sprengringe, Klemmen, Klammern oder Keile / B23K Löten , SOLDERING OR UNSOLDERING / B32B LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM , Schichtkörper, d.h. aus Ebenen oder gewölbten Schichten, z.B. mit zell- oder wabenförmiger Form, aufgebaute Erzeugnisse / B62D MOTOR VEHICLES , Motorfahrzeuge / C21D Veränderung der physikalischen Struktur von Eisenmetallen , MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS / C22C Legierungen , ALLOYS / C23C Beschichten metallischer Werkstoffe , COATING METALLIC MATERIAL |