An apparatus for heating steel products, in particular billets, includes a heating chamber, a plane of advance defined inside the heating chamber and feed and extraction components for the steel products.

A roll-transport device including: a roll that comes into contact with the base material; a support shaft that rotatably supports the roll; and a bearing that is disposed on an outer peripheral surface of the support shaft and has an end surface on one side in an axial direction, which faces an inside of a furnace, and an end surface on the other side in the axial direction, which is positioned on a side of an inner portion (space surrounded by the roll). A purge gas is caused to circulate from the end surface on the other side toward the end surface on the one side of the bearing, and the purge gas is discharged into the furnace from the end surface on the one side of the bearing.

A direct resistance heating method includes placing a first electrode and a second electrode such that a space is provided between the first electrode and the second electrode and such that each of the first electrode and the second electrode extends across a heating target region of a workpiece, moving at least one of the first electrode and the second electrode with an electric current being applied between the first electrode and the second electrode, and adjusting a time during which the electric current is applied for each segment region of the heating target region, the segment regions being defined by dividing the heating target region and are arranged side by side along a direction in which the at least one of the first electrode and the second electrode is moved.

A roller transport assembly includes a cart assembly and a roller carriage assembly. The roller carriage assembly is slidably mounted to the cart assembly and has at least one chamber for housing a roller. Each of the chambers includes a linear rail extending along a first axis and a roller coupling device attached to and slidable along the linear rail. The roller coupling device is operable to couple to the roller and move the roller along the first axis adjacent and parallel with the linear rail.

Provided is an electric resistance welded steel pipe or tube that develops no quench cracks despite having carbon content of 0.40% or more and has excellent fatigue strength. An electric resistance welded steel pipe or tube comprises: a chemical composition containing, in mass %, C: 0.40% to 0.55%, Si: 0.10% to 1.0%, Mn: 0.10% to 2.0%, P: 0.10% or less, S: 0.010% or less, Al: 0.010% to 0.100%, Cr: 0.05% to 0.30%, Ti: 0.010% to 0.050%, B: 0.0005% to 0.0030%, Ca: 0.0001% to 0.0050%, and N: 0.0005% to 0.0050%, with a balance consisting of Fe and inevitable impurities; and a ferrite decarburized layer at each of an outer surface and an inner surface, the ferrite decarburized layer having a depth of 20 ?m to 50 ?m from the surface.

By optimizing equipment and processing, magnetic domain miniaturization efficiency can be increased, workability can be improved, and processing ability can be increased through same. Provided is a method for miniaturizing the magnetic domains of a directional electric steel plate, the method comprising: a steel plate supporting roll position adjusting step of controlling the vertical direction position of a steel plate while supporting the steel plate progressing along a production line; and a laser emitting step of melting the steel plate by emitting a laser beam to form grooves on the surface of the steel plate, wherein the laser emitting step includes an angle changing step of changing an emitting line angle of the laser beam with respect to a width direction of the steel plate while an optical system emitting the laser beam onto the steel plate is rotated with respect to the steel plate, and a focal distance maintaining step of changing a tilt of the steel plate supporting roll which supports the steel plate according to a change in focal distance of the laser beam in the width direction of the steel plate.

The transverse flux induction heating device allows an alternating magnetic field to intersect the sheet face of a conductive sheet which is conveyed in one direction, thereby inductively heating the conductive sheet. The transverse flux induction heating device includes a heating coil disposed such that a coil face faces the sheet face of the conductive sheet; a core around which the heating coil is coiled; and a shielding plate formed of a conductor and disposed between the core and a side end portion in a direction perpendicular to the conveyance direction of the conductive sheet, wherein the shielding plate has a protruded portion, and the side surface of the protruded portion represents a closed loop when viewed from a direction perpendicular to the coil face.

A current applying apparatus includes a pair of electrodes configured to contact a workpiece to apply an electric current to the workpiece, and a bus bar arranged to extend along the workpiece. At least one of the electrodes includes a moving electrode configured to move relative to the bus bar and the workpiece such that an electric current flows between the bus bar and the workpiece through the moving electrode, the moving electrode being connected to the bus bar so as to be movable relative to the bus bar, and the moving electrode being configured to contact the workpiece so as to be movable relative to the workpiece.

A workpiece transport unit including a pair of arms, an opening/closing mechanism configured to open and close the pair of arms in a horizontal direction, a pair of first placement surfaces provided at the pair of arms and configured for a first workpiece to be placed thereon, and a pair of second placement surfaces provided at the pair of arms and configured for a second workpiece to be placed thereon.

A current applying apparatus includes a pair of electrodes configured to contact a workpiece to apply an electric current to the workpiece, and a bus bar arranged to extend along the workpiece. At least one of the electrodes includes a moving electrode configured to move relative to the bus bar and the workpiece such that an electric current flows between the bus bar and the workpiece through the moving electrode, the moving electrode being connected to the bus bar so as to be movable relative to the bus bar, and the moving electrode being configured to contact the workpiece so as to be movable relative to the workpiece.