An induction heating device having a control box, a magnetic core provided with at least one inductor fed with a current by a power electronics that is controlled by a control circuit, the power electronics and the control circuit being disposed in the control box, a removeable closing yoke for completing the magnetic circuit of the magnetic core, and a plurality of temperature sensors. A plurality of metal articles are simultaneously heated so as to each reach a target temperature and according to a heating cycle during which the temperatures sensors monitor the temperatures of the plurality of the metal articles so that each metal article is connected to a temperature sensor that is not connected to any other metal article.

The invention relates to a method for the induction hardening of a workpiece, in particular a toothed and/or corrugated and/or ribbed workpiece such as a gear or saw blade, wherein a matchingly shaped induction loop is guided or set over the workpiece surface to be hardened, the induction loop being formed layer-by-layer by the additive application of material, and the induction loop being shaped to match the surface to be hardened.

Provided is a supporting structure for an induction heating coil and an induction heating device in which a surface of an induction heating coil is not formed of a coating film for insulation that generates a gas, and movement of the induction heating coil when the induction heating coil is energized can be suppressed. A supporting structure 4 of an induction heating device 1 includes a supporting column 20 and a plurality of restricting members 21. The supporting column 20 is disposed at an outer side in a radial direction of winding portions 13 of the induction heating coil 3, and extends in an axial direction S1. The restricting members 21 receive the induction heating coil 3 to restrict movement of the induction heating coil 3 in the axial direction S1 in an insulated state, and are supported by the supporting column 20.

A heating apparatus (2) includes a high frequency power supply (3), a left conductive plate (4), a right conductive plate (5), a left heating coil (11), and a right heating coil (12). The left heating coil (11) includes a left conductor portion (21). The left conductor portion (21) faces a gear tooth (7a) of a helical gear (7) and extends in a direction orthogonal to the direction in which the gear tooth (7a) extends. The left heating coil (11) includes a focusing magnetic body (31) which focuses magnetic flux in the left conductor portion (21) and concentrates the magnetic flux on a surface of the gear tooth (7a). The left heating coil (11) includes an upper inducing magnetic body (32) which induces a part of the magnetic flux flowing in a tooth root of the gear tooth (7a) into a tooth tip of the gear tooth (7a).

An induction coil with inner and outer coil segments joined together by a transition segment is arranged so that the outer coil segment generally inductively heat treats an annular outer region of a workpiece positioned under the coil, the inner coil segment generally inductively heat treats an annular inner region of the workpiece, and the transition segment traverses at least a portion of the width of the overall annular region of the workpiece to be heat treated. Relative arrangement of inner, outer and transition coil segments provides for controlled induction heat treatment across the overall annular region such as the gear teeth region of an intersecting axes or non-intersecting and non-parallel axes gear.

A method for joining a carburized steel workpiece to a cast iron workpiece is provided that includes tempering a localized area of the carburized steel workpiece, machining the localized area to reduce carbon content, and welding the carburized steel workpiece to the cast iron workpiece at the localized area. The tempering may be performed by induction heating and results in a hardness profile of the localized area of less than 50 HRC.

An induction heating device having a control box, a magnetic core provided with at least one inductor fed with a current by a power electronics that is controlled by a control circuit, the power electronics and the control circuit being disposed in the control box, a removeable closing yoke for completing the magnetic circuit of the magnetic core, and a plurality of temperature sensors. A plurality of metal articles are simultaneously heated so as to each reach a target temperature and according to a heating cycle during which the temperatures sensors monitor the temperatures of the plurality of the metal articles so that each metal article is connected to a temperature sensor that is not connected to any other metal article.

Provided is a supporting structure for an induction heating coil and an induction heating device in which a surface of an induction heating coil is not formed of a coating film for insulation that generates a gas, and movement of the induction heating coil when the induction heating coil is energized can be suppressed. A supporting structure 4 of an induction heating device 1 includes a supporting column 20 and a plurality of restricting members 21. The supporting column 20 is disposed at an outer side in a radial direction of winding portions 13 of the induction heating coil 3, and extends in an axial direction S1. The restricting members 21 receive the induction heating coil 3 to restrict movement of the induction heating coil 3 in the axial direction S1 in an insulated state, and are supported by the supporting column 20.

A heating apparatus (2) includes a high frequency power supply (3), a left conductive plate (4), a right conductive plate (5), a left heating coil (11), and a right heating coil (12). The left heating coil (11) includes a left conductor portion (21). The left conductor portion (21) faces a gear tooth (7a) of a helical gear (7) and extends in a direction orthogonal to the direction in which the gear tooth (7a) extends. The left heating coil (11) includes a focusing magnetic body (31) which focuses magnetic flux in the left conductor portion (21) and concentrates the magnetic flux on a surface of the gear tooth (7a). The left heating coil (11) includes an upper inducing magnetic body (32) which induces a part of the magnetic flux flowing in a tooth root of the gear tooth (7a) into a tooth tip of the gear tooth (7a).

A method for joining a carburized steel workpiece to a cast iron workpiece is provided that includes tempering a localized area of the carburized steel workpiece, machining the localized area to reduce carbon content, and welding the carburized steel workpiece to the cast iron workpiece at the localized area. The tempering may be performed by induction heating and results in a hardness profile of the localized area of less than 50 HRC.