Warmgewalztes Stahlblech und Verfahren zur Herstellung davon

Details

Veröffentlichungs-Nr.

EP4831326

Anmeldetag

15. Januar 2025

Veröffentlichung

7. August 2025

Rechtsraum

EP

IPC

C22C38/00, C21D9/46, C22C38/60

Abstract

Provided are a hot-rolled steel sheet with a yield strength of 700 MPa or higher and excellent ductility and shearability, and a method for producing the same. The hot-rolled steel sheet has a chemical composition including C, Si, Mn, P, S, Al, N, and Ti, and other optional components, and has a ratio of (the area fraction of regions with KAM values ranging from 1.0 to 4.0)/(the area fraction of regions with KAM values of less than 1.0) of 0.05 or higher, a coefficient of variation in crystal grain size of 0.55 or higher, a solid-solution Ti content in steel of 0.03% or less, an average particle size of Ti-containing carbides of 10 nm or less, a yield strength of 700 MPa or higher, and a uniform elongation of 8.5% or higher. The method for producing the hot-rolled steel sheet includes a rough rolling step of rough-rolling a steel material with the foregoing chemical composition after heating it, or without heating it after casting, the rough rolling step including setting the rough rolling finish temperature to 1000°C to 1100°C; a finishing rolling step including setting the rolling start temperature to 950°C or higher, and setting the total rolling reduction for first and second passes to 70% or less; a cooling step; a coiling step; and a coil cooling step after coiling.

Anmelder

Firma

JFE Steel Corporation

Land

🇯🇵 Japan

Fachgebiete