Schweissverbindung

Details

Veröffentlichungs-Nr.

EP4759953

Anmeldetag

7. Mai 2024

Veröffentlichung

13. Februar 2025

Rechtsraum

EP

Abstract

The present invention has as its technical problem to obtain a welded joint with an excellent LME resistance at the time of production. The welded joint of the present invention comprises a plurality of steel sheets overlaid, a nugget joining the plurality of steel sheets, a spot welded part having a pressure contact zone and a heat affected zone formed around the nugget, a non-heat affected zone of a region at the outside of the heat affected zone, and a separation zone formed around the pressure contact zone, wherein among the plurality of steel sheets, at least the one steel sheet arranged at the outermost side is a high strength steel sheet with a Vickers hardness at a center of sheet thickness of 240 Hv or more, the high strength steel sheet has a predetermined chemical composition, at a position of 50 µm to the outside from the end of the pressure contact zone, a high ferrite layer with an area ratio of ferrite phases of 90% or more is present in a thickness direction of the high strength steel sheet from a surface of the high strength steel sheet by a 5 µm or more thickness, and, at a position of 50 µm to the outside from the end of the pressure contact zone, a concentrated B part with a B intensity of 2 times or more of the B intensity of a depth of 50 µm found by TOF-SIMS measurement is present at a 1.0 µm or more thickness from the surface of the high strength steel sheet.

Anmelder

Firma

Nippon Steel Corporation

Land

🇯🇵 Japan