Abstract: A quenching depth measuring method is used for measuring the quenching depth in a workpiece and includes the steps of: magnetizing the workpiece by disposing, in the vicinity of the workpiece, a magnetizer equipped with an exciting coil; detecting, through a detection coil, an induced magnetic field generated by the magnetization; measuring the induced magnetic field as the output voltage of the detection coil; and specifying the thickness of the quenched hardened layer of the workpiece on the basis of known electromagnetic characteristic information of an unquenched material and a fully-quenched material and an output voltage value measured by the detection coil, the unquenched material being made of the same material as the constituent material of the workpiece and being a material on which a quenching process is not performed, the fully-quenched material being a material on which the quenching process is performed.

Abstract: Object of the present invention is to provide a welding method prevented the fracture at the spot welding zone by recovering the strength of a spot welding zone, namely, the ductility and the toughness in the spot welding zone, and a weld structure manufactured by the method. In the welding method, a spot welding zone provided with a weld nugget 13a is formed by conducting spot welding on the heat treated steel sheets in a stack; the spot welding zone is tempering treated by the high-frequency electrical current application to make the weld nugget have a hardness of 150% or less of the hardness of the heat treated steel sheets, and the heat affected zone surrounding the weld nugget is made to have a hardness of 30% to 90% of the hardness at the weld nugget before the tempering treatment by the high-frequency electrical current application.

Abstract: A heating apparatus, a heat treatment apparatus, and a heating method are provided. The heating apparatus includes a workpiece support on which a ring-shaped workpiece is placed, a rotary drive assembly, and a heater configured to heat the workpiece. The workpiece support includes a plurality of rotating rollers arranged in a circumferential direction. The rotary drive assembly is configured to rotate the plurality of rotating rollers to rotate the workpiece placed on the workpiece support along a ring shape of the workpiece. The heater includes a heating coil configured to induction-heat the workpiece on the workpiece support at a heating position, and an actuator configured to move the heating coil at the heating position relative to the workpiece to adjust a distance between the workpiece and the heating coil.

Abstract: The core metal for resin welding improves bonding strength between an outer peripheral resin member and the core metal. The outer peripheral resin member 30 is welded to the peripheral surface 21 of the core metal 20 by fitting the core metal into a fitting hole 31 of the outer peripheral resin member 30, preparing the outer peripheral resin member 30 providing the fitting hole 31 with a smooth internal wall surface; preparing the core metal 20 wherein streaky protrusions 26 and smooth portions 25 are provided; allowing the top parts of the protrusions 26 to contact, and the smooth portions of the core metal 20 to face the smooth internal wall surface; and induction heating to weld the outer peripheral resin member 30 to the protrusions 26 and the smooth portions 25.

Abstract: A rebar structure includes a plurality of column longitudinal bars to be connected to a beam. The yield point or the 0.2% proof stress of at least a portion the column longitudinal bars is larger than the yield point or the 0.2% proof stress of a normal reinforcing bar defined by JIS G 3112.

Abstract: A wire heating system includes an induction heating apparatus having a power supply and an induction coil arranged to heat a wire rod by an induction heating using current supplied from the power supply, and a controller configured to control the current to be supplied to the induction coil based on a feeding speed of the wire rod. The induction heating apparatus has a heating section in which the wire rod is heated by the induction heating using the induction coil, and a soaking section located downstream of the heating section to homogenize the temperature distribution of the induction-heated wire rod. The controller is configured to control the current to be supplied to the induction coil such that a temperature of the wire rod at a downstream end of the soaking section becomes a target temperature.

Abstract: A main reinforcing bar has a strength transition portion between a normal strength portion and a high strength portion. The high strength portion is arranged in a joint section. The boundary between the normal strength portion and the strength transition portion is configured as a deigned point. The designed point is designed such that, at the time of an earthquake, the main reinforcing bar yields at the designed point before the main reinforcing bar yields at the root of the beam at of the joint section. The boundary between the high strength portion and the strength transition portion is located in the joint section, and the root of the beam is located at the strength transition portion. The strength of the strength transition portion at the root of the beam is equal to or higher than the required strength.

Abstract: A welding equipment for metallic materials capable of performing heat treatment such as tempering based on partial heating in spot welding is provided. The welding equipment sandwiches metallic materials with a pair of electrodes, and heats different regions of the metallic materials by energization, with the pair of electrodes maintained at the same position with respect to the metallic materials. The welding equipment includes a first heating means connected to the pair of electrodes for heating and welding the internal region of the circle defined by projecting the cross-sectional area of the axis of the electrodes on the metallic materials by applying power having a low first frequency, a second heating means for heating a ring-shaped region along the circle by applying power having a second frequency that is higher than the first frequency, and an energization control unit for independently controlling the first and the second heating means.

Abstract: A heating coil 21 includes: at least a set of heating conductors 23, 24, one of which is arranged at a side of a work 10 and the other one is arranged at an opposite side of the work 10; and a plurality of connecting conductors 29 to connect an end of one of the heating conductors 23, 24 with an end of the other heating conductor 23, 24, wherein the set of heating conductors 23, 24 faces a part of the work 10, each of the heating conductor 23, 24 is connected with at least two connecting conductors 29; and the connecting conductors extend from an end of each of the heating conductor 23, 24 in a different direction from each other.

Abstract: A hollow rack bar and a method of manufacturing the hollow rack bar are provided. The hollow rack bar includes a hollow blank pipe portion having a uniform wall thickness, and a rack toothed portion. The rack toothed portion includes teeth, a flat portion having a flat surface and arranged side by side with the teeth in a direction along a center axis of the blank pipe portion, and a slanted portion provided at an end of the flat portion with respect to a direction perpendicular to the center axis and arranged to be lower than the flat portion. A length of the slanted portion projected on a straight line perpendicular to the center axis and parallel to the surface of the flat portion is longer than zero and equal to or shorter than the wall thickness of the blank pipe portion.

Abstract: A welding equipment for metallic materials capable of performing heat treatment such as tempering based on partial heating in spot welding is provided. The welding equipment 1 sandwiches metallic materials 9 with a pair of electrodes 4, 4, and heats different regions of the metallic materials 9 by energization, with the pair of electrodes 4, 4 maintained at the same position with respect to the metallic materials 9. The welding equipment includes a first heating means 6 connected to the pair of electrodes 4, 4 for heating and welding the internal region of the circle defined by projecting the cross-sectional area of the axis of the electrodes on the metallic materials by applying power having a low first frequency, a second heating means 8 for heating a ring-shaped region along the circle by applying power having a second frequency that is higher than the first frequency, and an energization control unit 10 for independently controlling the first and the second heating means 6, 8.

Abstract: A direct resistance heating method includes placing a first electrode and a second electrode on a plate-shaped workpiece such that the first electrodes and the second electrode extend across the workpiece in a direction substantially perpendicular to a center line of a heating target region of the workpiece, the center line connecting a middle portion of one side of the heating target region and a middle portion of the other side of the heating target region; and moving at least one of the first electrode and the second electrode along the center line while applying electric current between the first electrode and the second electrode.

Abstract: The present invention includes a bar having a maximum cross section region smaller than a minimum cross section region of a hollow portion of a pipe P, and projected portions mounted along an axial direction of the bar and including a projected portion with maximum extent Hb, extent Ha of the projected portion positioned at a leading end side of the bar is set to be smaller than extent Hb of the projected portion positioned at a center side in the axial direction, and extent Hc of the projected portion positioned at a base end side of the bar is set to be less than or equal to extent Hb of the projected portion.

Abstract: The present invention includes: a hardening control unit (70) for controlling an induction hardening apparatus (10, 10A) based on setup conditions data regarding the induction hardening apparatus (10, 10A); a hardening monitoring unit (20) that measures, as measurement data, the electric quantity in an electric circuit configured to include a high-frequency inverter (11), a capacitor (12), and a heating coil (14, 14A, 14B) and that monitors an induction hardening status; and a data collecting unit (80) that collects the data from various sensors in the induction hardening apparatus (10, 10A, 10B) obtained when the induction hardening apparatus (10) subjects the work (15, 15A, 15B) to an induction hardening based on the setup conditions data outputted from the hardening control unit (70) and that collects the measurement data from the hardening monitoring unit (20) to store the collected data from the various sensors and the measurement data so that the collected data from the various sensors and the measureme

Abstract: A high-strength die-quenched part 1 is formed by heating a high-strength steel sheet 11 up to an austenite region, hot stamping and cooling inside a mold, and its microstructure has the martensite wherein carbide particles 2 are finely dispersed over an entire region including prior-austenite grain boundaries. It is desirable that the prior-austenite grain size in the microstructure of the high-strength steel sheet, which is a base material, be 10 ?m or smaller. The high-strength die-quenched part has high-strength and high-ductility thanks to its martensite.

Abstract: A method of annealing a copper wire for an interconnector includes heating a copper wire by a direct resistance heating or by an induction heating, a heating temperature of the heating being in a range of 650° C. to 1020° C., and a heating time of the heating being in a range of 0.3 seconds to 5 seconds.

Abstract: An induction heating device and an induction heating method are provided. The entire areas to be heated of the workpiece, even a large workpiece, can be readily and approximately uniformly heated to a predetermined high temperature, and uniform heating is possible even when the workpiece deforms in a non-uniform manner during heating. When areas to be heated H1, H2 are established on a workpiece W so as to extend in one direction and the areas to be heated H1, H2 are induction-heated, the deformation amount on one edge of the areas to be heated H1, H2 is different from that on the other. This induction heating device includes: heating coils 451 facing a portion of the areas to be heated H1, H2 when the workpiece W is induction-heated; and a relative transfer means for transferring the workpiece W and the heating coils 451 along one direction in a relative manner, and the heating coils 451 are disposed so as to correspond to the areas to be heated H1, H2 during the heating period.

Abstract: A rack bar includes a shaft portion and a rack toothed portion provided on the shaft portion. The rack toothed portion includes a plurality of rack teeth provided side by side in an axial direction of the shaft portion to mesh with a pinion gear. Each of the rack teeth includes a tooth tip portion, a contact face arranged obliquely relative to the axial direction and configured to contact the pinion gear, and a rounded corner portion between the tooth tip portion and the contact face. A first radius defining a central area of the rounded corner portion with respect to a tooth width direction is larger than a second radius defining another area of the rounded corner portion other than the central area.

Abstract: With a first push rod which is to be inserted/removed into/from a steel pipe through an opening at one end and a second push rod which is to be inserted/removed into/from the steel pipe through an opening at the other end, a metal core disposed on a side on which the first push rod is inserted/removed into/from the die assembly is sandwiched and this metal core is stopped from rotating with the first push rod. With the state of stopping the rotation of the first push rod, the metal core is introduced into the steel pipe through the opening at the one end by both the push rods. After the metal core is pressed into the steel pipe while stopped from rotating with the first push rod, this metal core is pushed back by the second push rod.

Abstract: The one end side portion is nipped by a jig including a jig member having a pair of convex portions which are to be fitted to a depressions in contact with a tooth side face and a inclined portion and positioning a bar and a jig member which is to be clamped/opened with respect to the jig member. A die having an inside diameter smaller than the diameter of the outer periphery is pressed onto the outer periphery of the end portion of the cylindrical end side portion projected from the jig up to a press-in depth determined preliminarily based on the rack, so as to reduce the diameter of the end portion.