High-strength, hot-rolled flat steel product with high edge crack resistance and simultaneously high bake-hardening potential, and method for producing a flat steel product of this kind

• Main Authors: WITTELER PATRICK, SCHOTTLER JOACHIM, PELZ CHRISTIAN, DENKS INGWER
• Format: Patent
• Language: Chinese; English
• Published: 03.07.2020
• Subjects: ALLOYS; CHEMICAL SURFACE TREATMENT; CHEMISTRY; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATIONOR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY IONIMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING MATERIAL WITH METALLIC MATERIAL; COATING METALLIC MATERIAL; DIFFUSION TREATMENT OF METALLIC MATERIAL; FERROUS OR NON-FERROUS ALLOYS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUSMETALS OR ALLOYS; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION INGENERAL; MAKING METAL MALLEABLE BY DECARBURISATION, TEMPERING OR OTHERTREATMENTS; METALLURGY; METALLURGY OF IRON; MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THESURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; TREATMENT OF ALLOYS OR NON-FERROUS METALS

The invention relates to a high-strength, hot-rolled flat steel product with high edge crack resistance and simultaneously high bake-hardening potential made of a steel with a yield strength Rp 0.2 of660 to 820 MPa, a BH2 value of more than 30 MPa, and a hole expansion ratio of more than 30%, and a structure consisting of two main constituents, wherein a first main constituent of the structure accounts for a proportion of at least 50%, consisting of one or more individual constituents of ferrite, tempered bainite, and tempered martensite, each with less than 5% carbides, and wherein a secondmain constituent of the structure accounts for a proportion of 5% to 50%, consisting of one or more individual constituents of martensite, residual austenite, bainite or perlite with the following chemical composition of the steel (in % by weight): C: 0.04 to 0.12; Si: 0.03 to 0.8; Mn: 1 to 2.5; P: max. 0.08; S: max. 0.01; N: max. 0.01; AI: up to 0.1; Ni+Mo: up to 0.5; Nb: up to 0.08; Ti: up to 0.2; Nb+Ti: min. 0.03; Cr: u