STEEL PLATE AND METHOD FOR MANUFACTURING STEEL PLATE

• Main Authors: IKEDA, Arisa, TAKEDA, Kengo
• Format: Patent
• Language: English; French; German
• Published: 13.03.2024
• Subjects: ALLOYS; APPARATUS THEREFOR; CHEMISTRY; ELECTROFORMING; ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; FERROUS OR NON-FERROUS ALLOYS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUSMETALS OR ALLOYS; MAKING METAL MALLEABLE BY DECARBURISATION, TEMPERING OR OTHERTREATMENTS; METALLURGY; METALLURGY OF IRON; MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTIONOF COATINGS; TREATMENT OF ALLOYS OR NON-FERROUS METALS

In a steel sheet according to the present embodiment, a Ti content and a N content satisfy Ti - 3.5 × N ≥ 0.003, at a sheet thickness 1/4 position, a metallographic structure includes 90% or more of martensite in terms of volume fraction, at the sheet thickness 1/4 position, a number density of TiC having a circle equivalent diameter of 1 to 500 nm is 3.5 × 104 particles/mm2 or more, at the sheet thickness 1/4 position, a value of a median value of a Mn concentration + 3σ is 5.00% or less, and a hardness measured at the sheet thickness 1/4 position is 1.30 times or more a hardness measured at a position 50 µm deep from a surface of the steel sheet.