BUMPER REINFORCEMENT AND METHOD FOR MANUFACTURING THE SAME

• Main Authors: KAJIWARA HIROYUKI, SHIMOAKA SHINGO, HASHIMOTO NARIKAZU, TSUYOSHI TSUNETAKE
• Format: Patent
• Language: English
• Published: 18.03.2015
• Subjects: CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS ANDNON-FERROUS ALLOYS; CHEMISTRY; FERROUS OR NON-FERROUS ALLOYS; MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVINGMATERIAL; METALLURGY; PERFORMING OPERATIONS; PUNCHING METAL; TRANSPORTING; TREATMENT OF ALLOYS OR NON-FERROUS METALS; VEHICLES IN GENERAL; VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISEPROVIDED FOR; WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS ORPROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL

A bumper reinforcement is formed of a 7000 series aluminum alloy hollow extrusion and has crushed end portions. A portion of the end portions is heated to a temperature of 400 DEG C. or more for reversion treatment, the heated portion is subjected to cold crushing, and then the whole bumper reinforcement is subjected to age hardening. Because of the age hardening, the heated portion has higher Vickers hardness than non-heated portions by Hv 10 or more. This compensates for a decrease in reaction force in a collision of an end portion resulting from a decrease in the section modulus of the crushed portion and thereby suppresses a decrease in energy absorption.