Provided is a frame member formed by hot-stamping a steel sheet. The frame member has a closed cross section portion in which a cross section perpendicular to a longitudinal direction is a closed cross section, and the closed cross section portion has at least two flat parts having a radius of curvature larger than a maximum external dimension of the cross section, and a recessed bead part formed between the two flat parts. The recessed bead part has a pair of wall portions which have a radius of curvature of 50 mm or greater, and protrude toward an inside of the closed cross section portion from end portions of the two flat parts facing each other via a pair of bent portions bent toward an inside of the closed cross section. A Vickers hardness of a thickness middle portion in the wall portion is 520 Hv or greater, a width of the wall portion is 0.5 times or greater and 2.5 times or less an effective width We, and a standard deviation ratio obtained by dividing a standard deviation of hardness frequency distribution in a surface layer portion in the wall portion by a standard deviation of hardness frequency distribution in the thickness middle portion in the wall portion is less than 1.0.
SKELETON MEMBER
SKELETTELEMENT
ÉLÉMENT DE SQUELETTE
2024-03-13
Patent
Elektronische Ressource
Englisch
IPC: | B21D WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL , Bearbeiten oder Verarbeiten von Blechen, Metallrohren, -stangen oder -profilen ohne wesentliches Abtragen des Werkstoffs / B21C MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES, PROFILES OR LIKE SEMI-MANUFACTURED PRODUCTS OTHERWISE THAN BY ROLLING , Herstellen von Blechen, Metalldraht, -stangen, -rohren Metallprofilen oder Halbzeugen auf andere Weise als durch Walzen / B62D MOTOR VEHICLES , Motorfahrzeuge |