Mit Zink Plattiertes Stahlblech und Herstellungsverfahren dafür

Details

Veröffentlichungs-Nr.

EP4786629

Anmeldetag

11. Dezember 2024

Veröffentlichung

17. Juli 2025

Rechtsraum

EP

Abstract

Provided are a zinc or zinc alloy coated or plated steel sheet having excellent delayed fracture resistance in stretch flanged areas, and a method of producing same. The zinc or zinc alloy coated or plated steel sheet includes a base steel sheet and a zinc or zinc alloy coated or plated layer formed on the surface of the base steel sheet. The base steel sheet has a defined chemical composition. The base steel sheet has a defined microstructure at a 1/4 sheet thickness position. A thickness of a carbon concentration reduced portion in the surface layer of the base steel sheet is 1.0 µm or more and 150.0 µm or less. A thickness of a bainite precipitation region directly below the carbon concentration reduced portion is 10 µm or more. A total coverage of retained austenite and fresh martensite at prior austenite grain boundaries directly below the carbon concentration reduced portion is 30.0 % or more and 60.0 % or less. A carbon concentration of retained austenite covering the prior austenite grain boundaries is less than 0.60 mass%. The tensile strength is 1470 MPa or more.

Anmelder

Firma

JFE Steel Corporation

Land

🇯🇵 Japan