CURVED METALLIC MATERIAL AND PROCESS FOR PRODUCING SAME

• Main Authors: ISHII KAZUYA, SHIMADA NAOAKI, KOJIMA NOBUSATO, TOMIZAWA ATSUSHI, NAKAMURA TOYOMITSU, TOKI TAMOTSU, IMAI KAZUHITO
• Format: Patent
• Language: English; Korean
• Published: 22.07.2013
• Subjects: 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; 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; MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVINGMATERIAL; METALLURGY; METALLURGY OF IRON; MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; PERFORMING OPERATIONS; PUNCHING METAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THESURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; TRANSPORTING; WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS ORPROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL

A bent metal member which is obtained by bending accompanied by heat treatment of a zinc-based coated metal material and which is suitable for use in components of automobiles due to having a high strength and excellent post-painting corrosion resistance is manufactured. The outer surface of a tubular metal material having on its surface a Zn-Fe alloy coating layer with a coating weight of 30 - 90 g/m 2 per side, an Fe content of 8 - 20%, and a surface roughness Ra of at most 0.8 µm is supported at two locations spaced in the axial direction of the metal material so that the material can move in its axial direction, the metal material is heated between the two locations to a temperature range of at least the Ac 3 point at a heating speed such that the rate of temperature increase is at least 3.0 x 10 2 °C per second while feeding the metal material in its axial direction, holding so that the length of time for which the surface of the metal material is at 8.0 x 10 2 °C or higher is at most 2 seconds, then rapid cooling is carried out, and the position of the downstream of the two locations in the feed direction of the metal material is two-dimensionally or three-dimensionally varied to impart a bending moment to the heated portion of the metal material. A bent metal member having a Zn-based layer which contains an · phase and which has a coating weight of 30 - 90 g/m 2 per side, an Fe content of 8 - 35%, and a surface roughness Ra of at most 2.0 µm can be manufactured.