Abstract: A laser processing machine to perform laser processing by focusing a laser beam onto a workpiece, includes a light-focusing optical system to focus the laser beam, wherein the light-focusing optical system has an aberration, and a lateral aberration with respect to a laser beam diameter:D86.5 containing 86.5% of the laser power of a laser beam before being focused is 0.2 mm or more, the lateral aberration being at a light focusing point relative to a light beam corresponding to the laser beam diameter:D86.5.

Abstract: A laser processing machine to perform laser processing by focusing a laser beam onto a workpiece, includes a light-focusing optical system to focus the laser beam, wherein the light-focusing optical system has an aberration, and a lateral aberration with respect to a laser beam diameter: D86.5 containing 86.5% of the laser power of a laser beam before being focused is 0.2 mm or more, the lateral aberration being at a light focusing point relative to a light beam corresponding to the laser beam diameter: D86.5.

Abstract: In a transverse induction heating apparatus in which a material to be rolled is heated by inductors to which electric power is supplied from an AC power source, iron core widths of the inductors in a plate width direction of the material to be rolled are smaller than plate width of the material to be rolled, they are disposed on a plate width center line of the material to be rolled, and when a current penetration depth is ?(m), specific resistance of the material to be rolled is ?(?-m), magnetic permeability of the material to be rolled is ?(H/m), heating frequency of the AC power source is f (Hz), and plate thickness of the material to be rolled is tw (m), the heating frequency of the AC power source is set so that ?={?/(?·f·?)}1/2 and (tw/?)<0.95.

Abstract: In a transverse induction heating apparatus in which a material to be rolled is heated by inductors to which electric power is supplied from an AC power source 4, iron core widths of the inductors in a plate width direction of the material to be rolled are smaller than plate width of the material to be rolled, they are disposed on a plate width center line of the material to be rolled, and when a current penetration depth is ?(m), specific resistance of the material to be rolled is ? (?-m), magnetic permeability of the material to be rolled is ? (H/m), heating frequency of the AC power source is f(Hz), and plate thickness of the material to be rolled is tw (m), the heating frequency of the AC power source is set so that ?={?/(?·f·?)}1/2 (tw/?)<0.

Abstract: According to the invention, the rear end of a preceding metal piece and a front end of a succeeding metal piece are heated, pressed and joined prior to the finishing hot rolling. An alternating magnetic field running through the metal pieces in the thickness direction thereof is generated in an end region on opposed faces of the respective metal pieces to perform heating. Another alternating magnetic field whose direction is reverse with respect to that of the former alternating magnetic field is partially generated in the end region on the opposed faces of the metal pieces and in either a region where the metal pieces exist or a region outside width ends of the metal pieces. This assures a uniform heating of the end region on the opposed faces of the metal pieces over their full width to reliably join the both metal pieces to each other.

Abstract: A method and apparatus for joining metal pieces wherein the rear end of a preceding metal piece and a front end of a metal piece are heated and then pressed together prior to hot finished rolling. The temperature the ends of the metal pieces are heated to is a temperature range between the solidus and liquidus line temperatures of the metal(s) to be joined.

Abstract: According to the invention, the rear end of a preceding metal piece and a front end of a succeeding metal piece are heated, pressed and joined prior to the finishing hot rolling. An alternating magnetic field running through the metal pieces in the thickness direction thereof is generated in an end region on opposed faces of the respective metal pieces to perform heating. Another alternating magnetic field whose direction is reverse with respect to that of the former alternating magnetic field is partially generated in the end region on the opposed faces of the metal pieces and in either a region where the metal pieces exist or a region outside width ends of the metal pieces. This assures a uniform heating of the end region on the opposed faces of the metal pieces over their full width to reliably join the both metal pieces to each other.

Abstract: Method and apparatus for joining metal pieces using induction heating. Metal pieces to be joined are placed end-to-end with a gap between them and induction heated in the thickness portion. To maximize speed and even heating edge-to-edge of the ends, members of a magnetic substance are provided in a gap between the inductor and the piece to be heated, thereby enhancing local heating effect by increasing magnetic flux density. Once heated, the ends are pressed together end-to-end for joining.

Abstract: An apparatus for joining metal pieces using induction heating. Preceding and succeeding metal pieces are followed by a carriage which carries an inductor. The inductor has the ability to move in the longitudinal direction of the metal pieces relative to the carriage to allow the inductor to move more or less upon the preceding or succeeding metal pieces to increase or decrease the induction heating effect, thereby taking into account any thickness variation of the metal pieces and yet still heating them evenly with regard to each other, prior to their being pressed against each other for joining before hot finishing rolling.

Abstract: According to the invention, the rear end of a preceding metal piece and a front end of a succeeding metal piece are heated, pressed and joined prior to the finishing hot rolling. An alternating magnetic field running through the metal pieces in the thickness direction thereof is generated in an end region on opposed faces of the respective metal pieces to perform heating. Another alternating magnetic field whose direction is reverse with respect to that of the former alternating magnetic field is partially generated in the end region on the opposed faces of the metal pieces and in either a region where the metal pieces exist or a region outside width ends of the metal pieces. This assures a uniform heating of the end region on the opposed faces of the metal pieces over their full width to reliably join the both metal pieces to each other.