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: An induction hardening monitoring apparatus (20) comprising: a current sensor (21) for detecting output current from a high-frequency inverter (11); a voltage sensor for detecting a voltage generated in a heating coil (14) connected between output terminals of the high-frequency inverters (11) together with a capacitor (12) in an equivalent circuit manner; and a controller (23) for monitoring a hardening processing based on a detection signal from the current sensor (21) and a detection signal from a voltage sensor (22), wherein the controller (23) monitors a hardening processing by calculating an effective value of output current from the high-frequency inverter (11) based on a detection signal from the current sensor (21) and calculating an effective value of voltage generated in a heating coil (14) based on a detection signal from the voltage sensor (22); or further calculating load impedance based on each effective value.

Abstract: A hardening apparatus (10), comprising a heating zone (20) induction heating coiled members (12) to a hardening temperature and cooling zone (30) rapidly cooling the coiled members (12) induction heated to the hardening temperature. A carrying route (22) for carrying the coiled members (12) in the direction of arrow A (carrying direction) while the coiled members are rotating and an induction heating coil (24) for induction heating the coiled members (12) being carried on the carrying route (22) while the coiled members are rotating are disposed in the heating zone (20). The large number of coiled members (12) are placed on the carrying route (22) at specified intervals so that the longitudinal direction thereof crosses the carrying direction and carried continuously.

Abstract: In an induction heating coil for heating a shaft member having multiple steps, annular conductors are separately disposed in the axis direction, the annular conductors having inner diameters so as to form predetermined gaps with outer peripheries of heating portions of the shaft member, the lengths of annular conductors (1, 2, and 3) are set so that the areas of the respective heating portions are approximately equal to each other, and the annular conductors are connected to each other in series, so that the respective step shaft portions of the shaft member are uniformly heated. The annular conductors described above may be formed to have shapes in conformity with the shapes of the heating portions of the shaft member and may be formed to have a step shape corresponding to steps of the shaft member having different outer diameters.

Abstract: A converter (311) converts an AC electric power (e) to the DC electric power with a DC voltage value corresponding to a setting. An inverter (312) is controlled by a frequency electric power control circuit (330) to convert the DC electric power to a dual frequency AC electric power for alternately outputting low and high frequencies at a frequency ratio (duty) corresponding to the setting. A matching transformer (321) having a tap (321C) at which the resonance impedance corresponds to the output impedance of a generator (310) receives the dual frequency AC electric power. A low-frequency series resonance circuit (325) or a high-frequency series resonance circuit (326) is caused to provide a series resonance, thereby causing an induction heating coil (200) to induction heat a workpiece-to-be-heated (201). In this way, the single generator (310) and the single induction heating coil (200) are used to effectively induction heat the workpiece-to-be-heated (201) by means of the dual frequency resonance.

Abstract: A hardening apparatus (10), comprising a heating zone (20) induction heating coiled members (12) to a hardening temperature and cooling zone (30) rapidly cooling the coiled members (12) induction heated to the hardening temperature. A carrying route (22) for carrying the coiled members (12) in the direction of arrow A (carrying direction) while the coiled members are rotating and an induction heating coil (24) for induction heating the coiled members (12) being carried on the carrying route (22) while the coiled members are rotating are disposed in the heating zone (20). The large number of coiled members (12) are placed on the carrying route (22) at specified intervals so that the longitudinal direction thereof crosses the carrying direction and carried continuously.

Abstract: In an induction heating coil for heating a shaft member having multiple steps, annular conductors are separately disposed in the axis direction, the annular conductors having inner diameters so as to form predetermined gaps with outer peripheries of heating portions of the shaft member, the lengths of annular conductors 1, 2, and 3 are set so that the areas of the respective heating portions are approximately equal to each other, and the annular conductors are connected to each other in series, so that the respective step shaft portions of the shaft member are uniformly heated. The annular conductors described above may be formed to have shapes in conformity with the shapes of the heating portions of the shaft member and may be formed to have a step shape corresponding to steps of the shaft member having different outer diameters.

Abstract: A converter (311) converts an AC electric power (e) to the DC electric power with a DC voltage value corresponding to a setting. An inverter (312) is controlled by a frequency electric power control circuit (330) to convert the DC electric power to a dual frequency AC electric power for alternately outputting low and high frequencies at a frequency ratio (duty) corresponding to the setting. A matching transformer (321) having a tap (321C) at which the resonance impedance corresponds to the output impedance of a generator (310) receives the dual frequency AC electric power. A low-frequency series resonance circuit (325) or a high-frequency series resonance circuit (326) is caused to provide a series resonance, thereby causing an induction heating coil (200) to induction heat a workpiece-to-be-heated (201). In this way, the single generator (310) and the single induction heating coil (200) are used to effectively induction heat the workpiece-to-be-heated (201) by means of the dual frequency resonance.

Abstract: A double tapered steel wire (S) is evenly heat treated over the entire length thereof. The wire (S) has its constant-diameter straight portion (21, 24) disposed between its opposite end tapered portions (22, 23) each tapered down to its reduced-diameter outer end. In heat treatments, a diameter of the wire (S) is continuously detected by a detection means (3, 6), so that the amount of energy of induction heating applied to the wire (S) is controlled by a control unit (12) in a manner such that the amount of the energy is proportional to a wire diameter of the wire (S) having been detected, whereby heat applied to the wire (S) varies over the entire length of the wire (S). As a result, the wire (S) is quenched and tempered over its entire length in a manner such that the wire (S) thus heat treated has its small-diameter portions (24) and its large-diameter portion (21) differ from each other in tensile strength.

Abstract: A double tapered steel wire (S) is evenly heat treated over the entire length thereof. The wire (S) has its constant-diameter straight portion (21, 24) disposed between its opposite end tapered portions (22, 23) each tapered down to its reduced-diameter outer end. In heat treatments, a diameter of the wire (S) is continuously detected by a detection means (3, 6), so that the amount of energy of induction heating applied to the wire (S) is controlled by a control unit (12) in a manner such that the amount of the energy is proportional to a wire diameter of the wire (S) having been detected, whereby heat applied to the wire (S) varies over the entire length of the wire (S). As a result, the wire (S) is quenched and tempered over its entire length in a manner such that the wire (S) thus heat treated has its small-diameter portions (24) and its large-diameter portion (21) differ from each other in tensile strength.