METHOD FOR HOT-STAMPING GALVANIZED STEEL SHEET

• Main Authors: KAWANO KAZUYUKI, KOBAYASHI YOSHIFUMI, YAEKURA TAKASHI, ITO YASUNORI
• Format: Patent
• Language: English; Korean
• Published: 14.03.2013
• Subjects: APPARATUS THEREFOR; 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; ELECTROFORMING; ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION INGENERAL; MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVINGMATERIAL; METALLURGY; PERFORMING OPERATIONS; PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTIONOF COATINGS; 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

In a cooling a galvanized steel sheet (W), change in emissivity of a surface of the galvanized steel sheet (W) is measured in a temperature range lower than the boiling point of zinc but not lower than the ferrite transformation temperature, using an emissivity sensor (4) with an observation wavelength of 1.4 µm or longer, and pressing and quenching in a pressing and quenching apparatus (2) is started after completion of an alloying reaction has been detected based on the change in emissivity. The emissivity sensor (4) preferably has an InGaAs element or a thermopile as a measuring element.