Abstract: C-shaped inductors for induction heating a heated steel material that is carried via table rollers. Each C-shaped inductor includes a C-shaped iron core having a pair of legs facing each other by sandwiching a gap through which the heated steel material passes, and heating coils wound around the pair of legs of the C-shaped iron core. A ring-shaped iron core for restricting induced currents generated in the heated steel material is disposed near the C-shaped inductors, and the heated steel material passes through the gap of each C-shaped inductor.

Abstract: This invention provides a method and apparatus for casting, hot rolling and annealing of non-heat treatable aluminum alloys which comprises continuously casting, hot rolling, and, in-line with the hot rolling line, inductively heating the aluminum sheet. The induction heating system uses a feedback control to assure that the aluminum alloy is heated to the proper temperature based on one or a number of process variables, such as hot rolling exit temperature, hot rolled product exit rate in terms of speed and product dimensions, and sheet temperature at the exit of the induction heater. Variations in the induction heating temperature can be tolerated in the product without deviating from target mechanical properties.

Abstract: A transverse flux heating coil is disclosed to inductively heat a continuous run of wire. In general, the transverse flux heating coil includes a single loop conductive element having a pair of termination ends extending therefrom and connectable to a power supply. The single loop conductive element is constructed to distribute the majority of the current across a width of the single loop conductive element and forms an internal heating area in which a continuous run of wire is fed therethrough. The flux generated by the current is generally transverse to a direction of travel of the wire through the heating coil. The transverse flux heating coil includes a first conductor having a width facing an internal heating area that is substantially greater than a thickness and is constructed of planar copper bar stock.

Abstract: A method and apparatus for induction heating includes a power supply, and a controller, and an induction head. The induction head includes a flexible coiled, such as one formed with Litz wire. The head also includes a thermal insulator, for disposing between the head and the workpiece. The insulator reflects heat back to the workpiece, protecting the coil, but is transparent to inductive (E-M) energy. The power supply is a variable output frequency power supply, such as one having a resonant tank, to adapt to the inductance of the head.

Abstract: An alloying system for a galvanized steel sheet, the alloying system using an induction heating coil, wherein an impedance matching apparatus is provided between the induction heating coil and a high frequency power source. The impedance matching apparatus comprises a matching transformer having a plurality of intermediate contact points for arbitrarily selecting a turn ratio, and a switching device for alternative changeover of the intermediate contact point, whereby even when the load impedance of the steel sheet varies, maximum power source output is obtained, such that an appropriate heating temperature necessary for forming an alloy layer of the steel sheet can be supplied.

Abstract: An apparatus for forming and consolidating organic matrix composites. An organic matrix composite panel comprising laid-up prepregs is placed between sheets of a susceptor material that is susceptible to inductive heating to form a workpiece. The resulting workpiece is placed within upper and lower dies formed of a material that is not susceptible to inductive heating. An induction coil embedded within the dies is energized and inductively heats the susceptor sheets surrounding the panel. The sheets in turn conductively heat the organic matrix composite panel. A pressure zone between the workpiece and one of the dies is pressurized to form the workpiece to the contour of a forming surface on one of the dies. The pressure in the pressure zone is maintained on the workpiece until the organic matrix composite panel is fully consolidated and formed.

Abstract: A furnace for heating ferrous metal workpiece is made up of a plurality of pairs of furnace sections with each pair of furnace section having a longitudinal flux inductors with controls for rapidly adjusting the heating rate according to a desired workpiece discharged temperature from the second of the furnace sections. The second furnace is controlled to maintain a substantially constant workpiece heating temperature. A second pair of furnace sections is provided with a first furnace section utilizing coil pairs with a dual output power supply having independent phase adjustable output currents to vary the current phase relation between the coils between 0 and 180°. The change to the phase relation is used to maintain efficient heating of the metal strip above the Curie temperature.

Abstract: An alloying system for a galvanized steel sheet, using an induction heating coil, wherein the temperature of the steel sheet in an induction heating furnace is measured based on the impedance of a high frequency heater, and the amount of heating is controlled by feedback, to form an alloy layer of the steel sheet.

Abstract: An induction heating workcell having a fixed solenoid coil heats parts more uniformly by aligning ferrite blocks, generally along the centerline of the coil, to improve uniformity of the magnetic field, magnetic flux, and power density. The blocks are nonconducting but have a high magnetic permeability so that flux prefers to travel through the block over surrounding structure. Therefore, the blocks are flux shapers that produce the desired temperature control.

Abstract: A sheet bar joining apparatus comprises a heater provided between a delivery-side clamp for clamping a rear end of a preceding sheet bar and an entry-side clamp for clamping a front end of a succeeding sheet bar; upper and lower anti-buckling plates provided on the entry-side clamp and located above and below the sheet bars; upper comb tooth portions and lower comb tooth portions formed in the upper and lower anti-buckling plates, respectively; a heat resistant insulator provided at a surface of each comb tooth portion opposed to the sheet bars; and a plurality of groove portions provided near the surface of each comb tooth portion opposed to the sheet bars.

Abstract: A composite material for electromagnetic fusion bonding materials together includes interconnected first and second portions forming a patterned array. The first portions include layer absorptive magnetic particles in a polymer matrix. The second portions include a polymer positioned to separate each first portion from each other first portion.

Abstract: The processing time and energy efficiency of metal or composite bonding operations is improved by heating the lay-up preform of the structure in an induction heating press where energy goes primarily to heating the workpieces rather than to heating the tooling or being lost to the environment. The bonding process is especially beneficial for joining thermoplastic composites, but it also can be used with metals or thermosets. Preferential heating at the bondline is achieved by using shims to define the bondline and to define bead regions that have relief from contact with the susceptor envelope because of the thickness of the shims in the bondline regions.

Abstract: A method and hot rolling apparatus for producing a hot rolled steel sheet include a roughing rolling mill to roughing roll a heated slab into a sheet bar, at least one solenoid-type induction heater arranged for re-heating the sheet bar over its entire width, and a finish rolling mill arranged to finish roll the re-heated sheet bar into a hot rolled steel sheet having a predetermined thickness. An initial temperature before rolling is set to be low, and re-heating of the sheet bar is carried out around the middle of the hot rolling apparatus. The thermal energy required for rolling is thereby reduced as a whole without damaging the quality of the resulting hot rolled steel sheet. A descaling apparatus is provided prior to the finish rolling mill to remove oxide scales on surfaces of the sheet bar, whereby the resulting hot rolled steel sheet is free of scale flaws and exhibits superior surface properties.

Abstract: Problems associated with accurately positioning a susceptor at the bond line between two or more prefabricated, fiber reinforced, resin composite detail parts to facilitate thermoplastic welding (i.e., fusion bonding) between the detail parts. The integrated susceptor detail part is compatible with Z-pinning along the bond line for the pulloff strength enhancement associated with Z-pin reinforcement. We make the parts by (1) preparing the faying overface of the prefabricated part or prepreg preform for the overlayment of the bond line materials, (2) placing a thermoplastic film on the part or preform, (3) placing the susceptor on the film, and (4) securing the film and susceptor to the part by applying suitable heat and pressure to produce a prefabricated, consolidated detail part having an integrated susceptor in a resin rich region intended as the bond line to other parts in the final assembly.

Abstract: Disclosed is a heating system for heating metal products in an oscillating induction furnace and a method of operation of the heating system. The heating system includes an oscillating induction furnace that in turn comprises a plurality of induction coils interspersed with a plurality of rollers. The metal products are oscillated within the induction coils on the plurality of rollers until heated to a target temperature. A logic device determines the power to be supplied to the induction coils, the number and speed of oscillation passes to conduct, the duration of time to be spent in the oscillating induction furnace, and the loading arrangement of the metal products within the oscillating induction furnace if two or more metal products are to be heated together in the oscillating induction furnace. The power supplied to the initial and final induction coils is metered by the logic device according to the proximity of the metal product to the initial and final induction coils.

Abstract: Problems associated with accurately positioning a susceptor at the bond line between two or more prefabricated, fiber reinforced, resin composite detail parts to facilitate thermoplastic welding (i.e., fusion bonding) between the detail parts. The integrated susceptor detail part is compatible with Z-pinning along the bond line for the pulloff strength enhancement associated with Z-pin reinforcement. We make the parts by (1) preparing the faying overface of the prefabricated part or prepreg preform for the overlayment of the bond line materials, (2) placing a thermoplastic film on the part or preform, (3) placing the susceptor on the film, and (4) securing the film and susceptor to the part by applying suitable heat and pressure to produce a prefabricated, consolidated detail part having an integrated susceptor in a resin rich region intended as the bond line to other parts in the final assembly.

Abstract: Rib and spar webs are joined in a composite wingbox to eliminate fasteners by welding the webs along bond lines defined by overlapping sections of the webs. Heat to produce the weld is generally achieved resistively by connecting a multistrip susceptor positioned along the bond line to a current source, since the geometry makes it difficult to heat these web joints inductively. The wingbox is completed without fasteners by welding skins to the rib-spar wingbox.

Abstract: An induction heating apparatus for heating continuous strip material. In a first embodiment, two coil sections each having a gap at one end for the strip material to pass edgewise into and out of the apparatus for heating wherein the coil sections are adapted for connection to two power supplies such that the first power supply connects through one half-turn of each of the coil sections, and thence to the second power supply, which is connected through the second half-turns of the respective coil sections and back to the first power supply, all in series. In a second embodiment, the coil sections are adapted for connection to four power supplies in series; each power supply connected to a respective half-turn of the coil sections, such that one half-turn is connected between each of the four power supplies. The series connection ensures uniform amplitude and phase of the electrical current applied to the induction heating coil apparatus.

Abstract: Multisheet SPF parts with braze joints at selected locations are produced with improved energy efficiency and at lower cost. The parts include a core defined with intermittent welds between two or more core sheets and aerodynamically smooth facing sheets brazed to the core. The manufacturing process includes heating the multisheet pack to its superplastic forming range below the melting point of the braze alloy, superplastically forming the pack to define braze joints having unmelted braze alloy; increasing the temperature to the braze temperature of the braze alloy, and cooling the pack below the superplastic range to freeze the braze alloy in the braze joint.

Abstract: A device for inductive cross-field heating of flat metallic goods has at least one pair of inductors having each one iron core provided with a groove for receiving a lead that extends in the transport direction. The grooves and leads of both inductors of a pair of inductors are mirror symmetrical and the leads of each inductor form two independently switchable lead systems. Each lead system has sections that extend substantially in the transport direction of the metallic goods and whose center lines extend symmetrically to a central axis of the inductor parallel to the transport direction. The individual poles of the lead systems consist of maximum two leads. Each pole of a lead system is arranged between the poles of the other lead system. A uniform temperature distribution in the goods to be heated is achieved by synchronizing the offsetting in time the moments when both lead systems are switched.

Abstract: Sesceptor sheets are selected so that their magnetic permeability decreases to unity at approximately the desired operating temperature thereby limiting heating to this "Curie temperature" and providing substantial uniformity of temperature in the panel Preferably, the susceptor includes multiple layers, such as a first metal having a relatively lower Curie temperature, a thin foil of copper in contact with the surface of the first sheet, and a second metal having a relatively higher Curie temperature. Such a susceptor allows thermal control at two spaced set points defined by the Curie temperatures.

Abstract: The processing time and energy efficiency of metal or composite bonding operations is improved by heating the lay-up preform of the structure in an induction heating press where energy goes primarily to heating the workpieces rather than to heating the tooling or being lost to the environment. The bonding process is especially beneficial for joining thermoplastic composites, but it also can be used with metals or thermosets. Preferential heating at the bondline is achieved by using shims to define the bondline and to define bead regions that have relief from contact with the susceptor envelope because of the thickness of the shims in the bondline regions.

Abstract: A heating system and method for heating a metal strip to within a predetermined temperature tolerance range while the metal strip serially travels through a heating system. The heating system has at least one preceding heating section, at least one induction heating section, and at least one following heating sections, with the heating sections being serially arranged. The metal strip is heated to below the Curie point of the metal strip in the preceding heating section. Next, the metal strip is heated to, at a maximum, approximately the Curie point in the induction heating section. Then, the metal strip is heated to above the Curie point and to within the predetermined temperature tolerance range in the following heating section.

Abstract: An apparatus for welding together two metal sheets (4, 5) includes clamping rails (17, 18; 23, 24) for positionally fixing the sheets (4, 5) each on a table (2, 3), and an induction device movable towards and away from a joint (15) between the metal sheets (4, 5) and along the direction (16) for heating the metal sheets (4, 5) in the joint region (1 5). The induction device displays a first conductor which extends along and adjacent the joint (15). The clamping rails (17, 18; 23, 24) are disposed two (17, 23) at the one sheet (5), and two (18, 24) at the other sheet (4), one on either side of each respective sheet, and along and a slight distance away from the joint (15). The clamping rails (17, 18; 23, 24) are disposed without electric conducting connection with the first conductor, are manufactured from electrically conductive material, and are electrically connected to the sheets (4, 5).

Abstract: Thermoplastic welding is an emerging technology targeted at significantly reducing the manufacture of aerospace structure by eliminating fasteners and the touch labor associated with fasteners to prepare, install, and inspect the assemblies. Thermoplastic welds, however, suffer from low pulloff strength because the metal foil susceptor used to heat the bondline is essentially a foreign substance in the weld that is unreinforced. The susceptor of the present invention provides Z-direction barbs on the susceptor to increase the pulloff strength.

Abstract: An adjustable width transverse flux heating apparatus for induction heating in the moving workpiece includes first and second elements disposed in the common plane to form an inductive coil. The first and second conductor elements define a middle spacing in an internal cross-section area of the inductive coil. A monitor detects workpiece fractures and generates signals relating thereto. A motor system moves one of the conductor elements relative to the other in response to the signal generated by the workpiece monitor.

Abstract: For forming or consolidating organic matrix composites, for example, an organic matrix composite panel is sealed between sheets of a susceptor material that is susceptible to induction heating. The susceptor sheets are heated inductively. The sheets in turn conduct heat to the organic matrix composite panel. When heated to the desired temperature, the composite panel is consolidated and/or formed. In the present invention, the susceptor sheets are selected so that their magnetic permeability decreases to unity at approximately the desired operating temperature thereby limiting heating to this "Curie temperature" and providing substantial uniformity of temperature in the panel. Of course, the concept applies to other induction heating operations for metals including SPF, brazing, annealing, heat treating, bonding, hot pressing, and the like.

Abstract: A fiber reinforcement fabric contains a metal susceptor strip paired with each warp thread and woven with the weave thread to produce a thermoplastic welding susceptor of separated and electrically isolated, longitudinal metal strips and fiber reinforcement in the weld.

Abstract: Fluid tooling for use in an inductive welding system for creating a fusion bond along a bond line between two thermoplastic parts includes an elongated vessel made of fluid impervious flexible material and having an elongated axis and an open end at each axial end of the vessel, closed and sealed by end closures. A coil is received in the vessel for generating an alternating magnetic field transverse to the longitudinal axis. A linear guide in the vessel extends axially for substantially the full length of the vessel and guides the coil for movement axially through the vessel. Power leads are connected to the coil and extend through a pass-through in one end closure to connect the coil to a source of high frequency electrical power of about 35 KHz to energize the coil to produce an alternating magnetic field.

Abstract: If internal support is required to keep thermoplastic parts from sagging during thermoplastic welding, silicone rubber bladder inflated to fill the space between the prefabricated composite parts, such as wingskins and spaced spars, provides positive reaction pressure. To protect the bladder we cover the sharp edges at the interface of the parts with foam or silicone rubber pads.

Abstract: We form welded reinforced composites by heating a susceptor along the bond line with a time-varying magnetic field produced with a moving induction coil. To obtain more uniform heating across the susceptor when welding composite parts using induction heating, edge regions of lower absolute impedance or a lower longitudinal impedance than the transverse impedance counterbalance the higher current density and current that occurs near the edges. The susceptor has lower impedance at the edges by altering the aspect ratio (length/width) of openings in the susceptor, by folding the susceptor over onto itself, or both. Uniform heating is important to obtaining a uniform, consistent weld on which aerospace designers can rely.

Abstract: Multisheet SPF parts with braze joints at selected locations are produced with improved energy efficiency and at lower cost by heating the multisheet pack to its superplastic forming range below the melting point of the braze alloy, superplastically forming the pack to define braze joints having unmelted braze alloy; increasing the temperature to the braze temperature of the braze alloy, and cooling the pack below the superplastic range to freeze the braze alloy in the braze joint.

Abstract: For forming or consolidating organic matrix composites, for example, an organic matrix composite panel is sealed in a "retort" between sheets of a susceptor material that is susceptible to induction heating. The susceptor sheets are heated inductively. The sheets in turn conduct heat to the organic matrix composite panel. When heated to the desired temperature, the composite panel is consolidated and/or formed. In the present invention, the susceptor sheets are selected so that their magnetic permeability decreases to unity at approximately the desired operating temperature thereby limiting heating to this "Curie temperature" and providing substantial uniformity of temperature in the panel. Of course, the concept applies to other induction heating operations for metals including SPF, brazing, annealing, heat treating, bonding, hot pressing, and the like.

Abstract: A process for consolidating a composite material comprises the steps of forming a workpiece including a matrix interspersed with fibers, supporting the workpiece by an electrically conductive support, inductively heating the support and thereby conductively heating the workpiece, and applying pressure to the heated workpiece. We apply the pressure by passing the support and workpiece through spaced rolls. To keep the workpiece from sticking to the support (i.e., the mandrel), we use boron nitride as a release agent.

Abstract: For economy of operation, as much as possible of the total length of a steel strip being rolled by a Steckel mill should be maintained at an acceptably high temperature. To this end, the trailing edge of the strip is drawn into the coiler furnace to the extent possible without losing driving control of the strip. This is enabled by providing within or in close proximity with the entrance/exit port of the coiler furnace a pair of preferably heated pinch rolls that drive the trailing edge of the strip (that has just completed a pass through the Steckel mill) into the coiler furnace as far as possible, leaving only a very short protruding portion of that trailing edge outside the coiler furnace. The strip may be left idle within the coiler furnace for as long a time as is required to bring the temperature of the wound strip up to a target operating temperature. Then the same pair of pinch rolls in or near the entrance/exit port of the coiler furnace drive the strip out of the furnace toward the Steckel mill.

Abstract: A fixed coil induction heater produces quality thermoplastic fusion welds in prefabricated resin composite parts. A susceptor along a bondline between parts aligns with the induction coil segments of a solenoid induction coil along the centerline of the coil. Energizing the coil heats the susceptor to form the weld at the bondline. For this operation, our induction heating workcell uses complementary dies that define a central cavity with an oval pattern of induction coil segments roughly conforming to the shape of the cavity and surrounding all faces of the cavity where we position the preform composite parts and susceptor.

Abstract: For forming or consolidating organic matrix composites, an organic matrix composite panel is placed between sheets of a susceptor material that is susceptible to induction heating. The susceptor sheets enclose the panel and define a retort. Peripheral gaskets temporarily seal the retort when the retort is placed within upper and lower dies of an induction heating workcell where the susceptor sheets are heated inductively. The sheets in turn conduct heat to the organic matrix composite panel. When heated to the desired temperature, the composite panel is consolidated and/or formed. In some circumstances, edge seal strips are used to provide electrical continuity between the upper and lower sheets in the retort. An analogous retort can be used for metal processing operations.

Abstract: An apparatus for forming and consolidating organic matrix composites. An organic matrix composite panel comprising laid-up prepegs is placed between sheets of a susceptor material that is susceptible to inductive heating to form a workpiece. The resulting workpiece is placed within upper and lower dies formed of a material that is not susceptible to inductive heating. An induction coil embedded within the dies is energized and inductively heats the susceptor sheets surrounding the panel. The sheets in turn conductively heat the organic matrix composite panel. A pressure zone between the workpiece and one of the dies is pressurized to form the workpiece to the contour of a forming surface on one of the dies. The pressure in the pressure zone is maintained on the workpiece until the organic matrix composite panel is fully consolidated and formed.

Abstract: A method and apparatus for forming and consolidating organic matrix composites. An organic matrix composite panel comprising laid-up prepregs is placed between sheets of a susceptor material that is susceptible to inductive heating to form a workpiece. The resulting workpiece is placed within upper and lower dies formed of a material that is not susceptible to inductive heating. An induction coil embedded within the dies is energized and inductively heats the susceptor sheets surrounding the panel. The sheets in turn conductively heat the organic matrix composite panel. A pressure zone between the workpiece and one of the dies is pressurized to form the workpiece to the contour of a forming surface on one of the dies. The pressure in the pressure zone is maintained on the workpiece until the organic matrix composite panel is fully consolidated and formed.

Abstract: A narrow susceptor is incorporated into the die in the vicinity of a bondline between two or more parts in an induction heating workcell. When the induction coil of the workcell is energized, the susceptor heats and preferentially heats the parts near the bondline. The preferential heating is localized at the bondline and reduces energy losses otherwise expended to heat large thermal masses in the workcell or to heat the entire parts.

Abstract: An induction furnace for homogeneously heating flat steel products fed therethrough in a continuous line in a predetermined feeding direction includes a succession of heating assemblies and pairs of rollers placed between the heating assemblies for supporting and moving the flat products in the feeding direction. Each heating assembly has a narrow induction coil fed by a separate frequency converter and a linear flux concentrator. The coil extends transverse to the feeding direction. The size of the coil in the feeding direction of the flat products is 350 mm. or less. The flux concentrator is in proximity of the coil and extends along the longitudinal orientation of the coil. The flux concentrator has ends, an upper portion and a lower portion. The upper and lower portions are joined at each of the ends, and establish a central gap therebetween for the flat products to pass therethrough. The gap extends through the heating assembly in a direction transverse to the longitudinal orientation of the coil.

Abstract: A method and apparatus for forming and consolidating organic matrix composites. An organic matrix composite panel comprising laid-up prepregs is placed between sheets of a susceptor material that is susceptible to inductive heating to form a workpiece. The resulting workpiece is placed within upper and lower dies formed of a material that is not susceptible to inductive heating. An induction coil embedded within the dies is energized and inductively heats the susceptor sheets surrounding the panel. The sheets in turn conductively heat the organic matrix composite panel. A pressure zone between the workpiece and one of the dies is pressurized to form the workpiece to the contour of a forming surface on one of the dies. The pressure in the pressure zone is maintained on the workpiece until the organic matrix composite panel is fully consolidated and formed.

Abstract: Induction heating apparatus for heating an elongate metal workpiece of predetermined width generates time varying magnetic fields which produce longitudinal eddy current distributions across the width of the workpiece having cosine and sine profiles. The amplitude of these profiles is not necessarily uniform across the width of the workpiece and the spatial period of these profiles across the workpiece width are chosen to ensure that the line integral across the workpiece of the eddy currents is zero. In this way a desired heating profile across the width of the workpiece can be maintained.

Abstract: An induction heating coil apparatus for heating continuous strip material comprising at least a pair of generally rectangular full-turn coils arranged in parallel relation and separated from each other to permit continuous strip material to pass axially through the open interiors of the coils. Each coil has an opening in a first end portion thereof such that continuous strip material may pass into or out of the interior of the coil apparatus. The coil apparatus further comprises a pair of shunt conductors connecting the respective coils to each other. The shunt conductors are arranged on opposite sides of the openings in the end portions of the coils for providing a continuous current path from one rectangular coil to the adjacent coil. In one preferred embodiment there is an opening in the second end portion of one coil. Two more conductors, one on each side of this opening, provide connection to the respective poles of an alternating current power source.

Abstract: A process for obtaining long, continuous, thermoplastic welds on large structures. A series of tabs are used in pairs and especially in alternating, overlapping pairs to obtain resistance heating of a strip material placed in the bond line. The resistance of the tabs is less than that of the strip material. Conducting braid-tubes afford continuous welding when the bond line is curved. Alternatively, an electromagnetic field is used to take advantage of the induction heating. A wide susceptor is used to weld a current conducting substrate while avoiding bulk heating of the substrate. The unexpected property of current-conducting braid-tube susceptors, in which induction heating takes place at the center rather than at the edges of a flattened braid-tube susceptor, is used to obtain long continuous curved welds.

Abstract: A metal matrix composite is made by roll consolidating a sandwich formed from alternating layers of a matrix metal, a brazing alloy, and reinforcing fiber at elevated temperature and pressure. If made in a process using mandrels to impart the pressure and heat, such as a process described in U.S. Pat. No. 5,229,562, the metal matrix composite is kept separate from the mandrels by using a release agent or stop-off such as a layer of boron nitride between the mandrel and layup.

Abstract: Transverse flux heating assembly for inductively heating a moving strip includes opposite spaced J-shaped conductors to form an inductive heating coil. The coils define a middle spacing therebetween which is unobstructed by flux guides to permit free translation movement between the conductors in a direction parallel to the strip width. The inductors provide a fully adjustable coil width to accommodate different strip widths in the heating operation.

Abstract: An apparatus for the inductive cross-field heating of flat material includes a plurality of mutually opposite induction loops being disposed above and below the flat material. At least one pair of induction modules is formed of two induction modules being adjustable independently of one another in their position relative to the flat material. Each induction module has two mutually opposite U-shaped induction loops having geometries and dimensions which are invariable, base legs which can be positioned in such a way that they terminate at least a predeterminable distance in front of one edge of the flat material and within the width of the flat material, and two side legs which can be positioned in such a way that they project at least a predeterminable distance beyond the other edge of the flat material.

Abstract: Device for the induction heating of flat metallic products on the move with the aid of electrical coils provided on magnetic armatures arranged on either side of the large faces of the product to be heated, which moves continuously between the said coils, wherein the inductors are mechanically independent of each other and they are arranged symmetrically in relation to the median plane of the product so that the magnetic fields generated are in phase opposition, leading to a ring-like distribution of the currents induced in the product to be heated up.

Abstract: A drawing roller unit is constructed with a godet and an electric motor mounted on a common shaft. A passage is provided throughout the unit to convey a non-flammable scavenging gas through the motor and the godet to reduce the risk of explosion due to sparking by the electric motor and/or other electrical parts of the drawing roller. The gas introduced can leave the unit only through a narrow gap. The pressure of the gas is consequently above atmosphere pressure and prevents the entrance of air.