Abstract: The laser irradiation step includes: removing zinc plating layers respectively disposed on the surfaces of the galvanized steel sheets by the laser irradiation; and melting the surfaces of the galvanized steel sheets of which the zinc plating layers have been removed, and the roller pressurizing step includes pressurizing the galvanized steel sheets by the rollers while the surfaces of the galvanized steel sheets that have been melted are in contact with each other such that the galvanized steel sheets are joined together.

Abstract: A press forming method is capable of improving material yield while avoiding the risk of dimensional error increase at product forming sections in blank material when carrying out press forming, and a plate material expansion device is used in this method. An end side of plate material for press forming is restricted by blank holding rollers, and pressure is applied to a middle location in the part that is restricted by a pressure roller. In this state, the plate material is transported in a rotating direction of the rollers being driven to continuously bend and extend the section receiving pressure. This bent and extended section is flattened with a flattening roller to obtain blank material wherein an end part is expanded.

Abstract: The laser irradiation step includes: removing zinc plating layers respectively disposed on the surfaces of the galvanized steel sheets by the laser irradiation; and melting the surfaces of the galvanized steel sheets of which the zinc plating layers have been removed, and the roller pressurizing step includes pressurizing the galvanized steel sheets by the rollers while the surfaces of the galvanized steel sheets that have been melted are in contact with each other such that the galvanized steel sheets are joined together.

Abstract: Provided are a press forming method capable of improving material yield while avoiding the risk of dimensional error increase at product forming sections in blank material when carrying out press forming, and a plate material expansion device used in this method. An end side of plate material for press forming is restricted by blank holding rollers, and pressure is applied to a middle location in the part that is restricted by a pressure roller. In this state, the plate material is transported in a rotating direction of the rollers being driven to continuously bend and extend the section receiving pressure. This bent and extended section is flattened with a flattening roller to obtain blank material wherein an end part is expanded.

Abstract: A device for forming a tailored blank plate 12 having a thick plate 14 connected to a thin plate 16 to a desired configuration is provided with a press device 10 and a re-strike device 100. The press device 10 is provided with a first punch part 18, a first die part 20 and holder parts 22 and 22. Between the first punch part 18 and the first die part 20, the tailored blank plate 12 is mounted and positioned so that a stepped part 12b intersects orthogonally to punch protruding parts 50a and 50b of the first punch part 18 and punch recessed parts 72a and 72b of the first die part 20 to press-form the tailored blank plate 12. Then, the press-formed tailored blank plate 212 is moved to the re-strike device 100 to carry out a re-striking process by a second punch part 102 and a second die part 104, so as obtain the tailored blank plate 300 of a final shape.

Abstract: A device for forming a tailored blank plate 12 having a thick plate 14 connected to a thin plate 16 to a desired configuration is provided with a press device 10 and a re-strike device 100. The press device 10 is provided with a first punch part 18, a first die part 20 and holder parts 22 and 22. Between the first punch part 18 and the first die part 20, the tailored blank plate 12 is mounted and positioned so that a stepped part 12b intersects orthogonally to punch protruding parts 50a and 50b of the first punch part 18 and punch recessed parts 72a and 72b of the first die part 20 to press-form the tailored blank plate 12. Then, the press-formed tailored blank plate 212 is moved to the re-strike device 100 to carry out a re-striking process by a second punch part 102 and a second die part 104, so as obtain the tailored blank plate 300 of a final shape.

Abstract: A method which is capable of completely separating a plate member with a large area without using a peeling member and eliminating a possibility of permanent deformation on the plate member. A plurality of suction pads are suckingly disposed on a surface of a topmost plate member in a substantially lattice shape. Then, while the topmost plate member is held by the suction pads disposed in a zigzag shape among the suction pads disposed in the substantially lattice shape, the topmost plate member is lifted by the remaining suction pads. Finally, the suction pads holding the topmost plate member are lifted.

Abstract: A method which is capable of completely separating a plate member with a large area without using a peeling member and eliminating a possibility of permanent deformation on the plate member. A plurality of suction pads are suckingly disposed on a surface of a topmost plate member in a substantially lattice shape. Then, while the topmost plate member is held by the suction pads disposed in a zigzag shape among the suction pads disposed in the substantially lattice shape, the topmost plate member is lifted by the remaining suction pads. Finally, the suction pads holding the topmost plate member are lifted.

Abstract: An aluminum alloy sheet for high-speed high-temperature blow forming has an aluminum alloy containing 4 to 5% of Mg, 0.35 to 0.5% of Mn and 0.001 to 0.05% of Cr, 0.6% or less of Si+Fe, 0.15% or less of Cu, and the balance being substantially Al. The aluminum alloy sheet has an elongation of 150% or more in a high-temperature tensile test at 400 to 550° C. and at a strain rate of 10?2/second or more, has a cavitation area percentage of 2% or less at the time of 100% tensile deformation, and is free from any abnormally grown grains of 100 microns or more. A formed piece of the aluminum alloy sheet also has a cavitation area percentage of 2% or less when blow-formed at 400 to 550° C. and at a reduction in sheet thickness of 65% or less, and is free from any abnormally grown grains of 100 microns or more.