Hochfestes Stahlblech und Verfahren zur Herstellung davon

Details

Veröffentlichungs-Nr.

EP4726069

Anmeldetag

9. Juli 2024

Veröffentlichung

30. Januar 2025

Rechtsraum

EP

Abstract

Objects are to provide a high strength steel sheet having a tensile strength of 980 MPa or greater and having excellent ductility, fatigue strength, and blankability and to provide a method for manufacturing the same. A high strength steel sheet has a predetermined chemical composition. In the high strength steel sheet, a primary phase is a bainite phase that includes upper bainite and granular bainite and is present in an area fraction of 85% or greater, and a hard secondary phase includes fresh martensite and/or retained austenite phases and is present in an area fraction of less than 15%; the area fraction of the granular bainite with respect to the area fraction of the upper bainite in the bainite phase is 5% or greater and 40% or less; a difference |Hv1 - Hv2| between a hardness Hv1 and a hardness Hv2 is 30% or less with respect to 0.3TS, where Hv1 is a hardness at a 1/2 thickness position, and Hv2 is a hardness at a 1/4 thickness position; and the upper bainite phase has an average grain size of 7 µm or less.

Anmelder

Firma

JFE Steel Corporation

Land

🇯🇵 Japan