Classifications

• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
  • C21D1/74—Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material
  • C21D1/767—Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material with forced gas circulation; Reheating thereof
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
  • C21D1/62—Quenching devices
  • C21D1/667—Quenching devices for spray quenching
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
  • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
  • C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
  • C21D9/54—Furnaces for treating strips or wire

Definitions

• the invention relates to a method for convective heat transfer between a heat transfer medium and a surface, in particular the end face of a wound metal strip in the form of a coil, the heat transfer medium being applied to the surface by means of at least one nozzle wall.
• the invention further relates to a device for performing the method for convective heat transfer between a heat transfer medium and a surface.
• heat transfer through forced convection plays a major role, since it can be used to transmit high power and achieve even temperature distributions.
• this method of heat transfer from a flowing fluid or gas to a workpiece requires a particularly uniform application of the respective heat transfer medium to the workpiece, since a uniform heat transfer must be ensured here without differences in local heat transfer resulting in different heating of the Guide the workpiece.
• the uniform exposure poses a major problem, for example, when heating metal strips which are wound into cylindrical coils. The heating of such coils typically takes place in chamber furnaces in which Reduction of the glow time of the workpieces, the highest possible heat transfer is sought.
• there can be large local differences in the heat transfer which leads to local overheating of the workpiece. This in turn causes material damage, for example in the form of discoloration or impairment of the desired metallurgical properties of the metal strips.
• a similar problem applies to the convective heat transfer when cooling a workpiece, which can lead to local hypothermia.
• Fixed nozzle walls are known from the practice of convective heating of metal strips in the form of wound coils, via which a fluid or gas is guided onto the end face of a cylindrical coil.
• perforated, tubular, slot or swirl nozzles are used to improve the heat transfer.
• a device for uniformly applying a fluid to a flat surface of a workpiece is known from German Patent 196 50 965 C1.
• the surface of the workpiece is preferably also the end face of a cylindrical band collar.
• the nozzle base for the application of the fluid is designed in such a way that devices for deflecting the nozzle jets in one direction are provided at the nozzle openings, which form an angle with the perpendicular to the nozzle base or, in the case of an essentially flat nozzle base, with its flat reference surface.
• the object of the invention is therefore to provide a method for the convective heat transfer between a heat transfer medium and a surface, in particular the end face of a metal strip in the form of a wound cylindrical coil, by means of which a heat transfer which is as uniform and high as possible is achieved without the workpiece is adversely affected.
• Another object of the invention is to provide a device for carrying out the method.
• this object is achieved in that in the case of convective heat transfer between a heat transfer medium and a surface, in particular an end face of a metal strip in the form of a wound coil, the surface is acted upon by the heat transfer medium by means of at least one nozzle wall, at least during the heat treatment move one of the nozzle walls and the surface to be treated towards each other.
• the object is further achieved in that in a generic device for convective heat transfer between a heat transfer means and a surface, in particular an end face of a metal strip in the form of a wound coil, means are provided for applying heat transfer means to the surface by means of at least one nozzle wall, at least one of the nozzle walls and the surface to be treated are movable relative to one another during the heat treatment.
• the nozzle walls can be designed to be movable while the coil is stationary. Furthermore, the coil can move while the nozzle walls are stationary, and a combination of the two previous designs can include both movable nozzle walls and coils.
• a design was chosen in which the nozzle walls are movable during the heat treatment and the coil is stationary.
• a chamber furnace of a known type is equipped in such a way that there is a nozzle wall on each of the two end faces of an inserted cylindrical coil, which can be rotated about an axis of rotation, the axis of rotation preferably corresponding to the main axis of the cylindrical coil or running essentially parallel thereto.
• the expression “essentially” includes angles of the order of 0 ° and 10 °.
• the rotatable nozzle walls are provided with several nozzles, the arrangement and design of which are suitable for the purpose. is cash.
• known perforated, tubular, slot and / or swirl nozzles can be used.
• a gas is conveyed as a heat transfer medium into the nozzle walls via a pressure box and flows through the nozzles onto the end faces of the coil to be heated or cooled.
• the rotation of the nozzle walls uniformly applies the gas to the two end faces, so that a very good heat transfer is guaranteed on the surface. Furthermore, due to the uniform application, there are no local temperature peaks or sinks at which areas of the workpiece to be treated are overheated or undercooled.
• the pictures show:
• Figure 1 shows a section through a particularly preferred embodiment of a device for convective heat transfer from a heat transfer medium to wound metal strips.
• FIG. 2 shows a front view of a device for convective heat transfer from a heat transfer medium to wound metal strips
• FIG. 3 shows an embodiment of a chamber furnace with an integrated device according to the invention.
• Fig. 4 tubular nozzle with inner swirl body.
• FIG. 1 shows a section through a particularly preferred exemplary embodiment of a device for convective heat transfer between a heat transfer medium and a surface, in particular the end face of a wound metal strip in the form of a cylindrical coil.
• a fluid or a gas can be used as the heat transfer medium.
• a gas is used for heat transfer.
• the device comprises a pressure box 20 into which the coil 30 to be heated or cooled is introduced.
• the coil is a cylindrically wound metal strip.
• the metal strip shown is wound around an axis 70 which runs horizontally in the figure, so that flat surfaces result on the end faces 31 and 32 of the coil.
• a nozzle wall 10 and 11 is located essentially parallel to these end faces of the coil.
• the mobility of the nozzle walls and the end faces of the coil in relation to one another is achieved in the exemplary embodiment shown by movable nozzle walls, while the coil is stationary during the heat treatment.
• the nozzle walls 10 and 11 are rotatable about an axis of rotation 71, which preferably corresponds to the main axis 70 of the cylindrical coil 30 or extends essentially parallel to it.
• the rotation of the nozzle walls takes place via a drive 40, which is not shown in detail in FIG. 1, but rather is marked in the drawing by ellipsoidal movement arrows.
• the gas for heating or cooling the coils can for example, be introduced into the pressure box 20 by means of a fan, not shown.
• the gas can be different types of gas that are suitable for the respective application.
• N 2 , N 2 H 2 , air, water vapor, protective gas, hydrogen, exogas or endogas can be used.
• the flow of the gas within the pressure box is marked with arrows.
• the gas flows through the nozzle walls 10 and 11 to one end of the coil.
• the nozzle walls have a plurality of openings, which can be shaped differently.
• slot nozzles 50 were selected, as can be seen in the illustration in FIG. 2.
• the gas flows out of the nozzle openings and impacts the end of the coil, where the heat transfer takes place. This applies to both the heating and the cooling of the coil material.
• the nozzle walls 10 and 11 In order to be able to adjust the device to the dimensions of different coils, for example, it has proven to be expedient to additionally design the nozzle walls 10 and 11 to be movable along their axis of rotation 71. This allows the distance 60 between the nozzle walls and the end faces of the coil to be set to the optimal distance for an effective flow.
• the drive 40 for this movement is not shown in detail in FIG. 1, but rather is identified by horizontal movement arrows.
• the seal can be adapted to the requirements in various ways.
• the sealing gap can be small or the seal can be designed as a labyrinth or contact seal.
• FIG. 2 shows a top view of a pressure chamber 20 with a circular nozzle wall 10.
• the rotating nozzle wall is designed with slot nozzles 50.
• other types of nozzles such as perforated, tubular or swirl nozzles can also be used.
• Pipe nozzles can, for example, be provided with an inner swirl body, as shown in FIG. 4.
• FIG. 3 shows a particularly preferred exemplary embodiment of a chamber furnace with an integrated device for heat transfer according to the invention.
• the pressure box 20 is located inside the furnace and a coil 30 to be heated or cooled is positioned between the two nozzle walls 10 and 11.
• the furnace is loaded with a coil from below, which is shown in the drawing below the chamber of the furnace by dashed lines.
• the usable space of the furnace can be divided using at least one retrofittable nozzle box. In this way, two or more coils can be placed in the usable space and loaded on both sides.
• Such an additional nozzle box is not shown in Figures 1-4.
• the chamber furnace is preferably controlled via control means with a program which expediently controls and regulates at least the temperature and the speed of the heat transfer medium in such a way that the best possible heat transfer occurs. If an embodiment is chosen with nozzle walls that are movable along its axis of rotation, the distance between the nozzle wall and the end face of the coil can also be controlled and be regulated so that the flow is as optimal as possible.
• the design according to the invention of a device with nozzle walls which are designed to be movable towards the end faces of the coil to be heated or cooled has various advantages. Due to the uniform exposure of the coil to the gas, there are no temperature peaks or sinks that could impair the coil material. For example, there is no discoloration or impairment of the desired metallurgical properties of the wound metal strip, so that the quality requirements can be met better and more easily.
• the uniform application of heat to the coil also leads to better heat transfer than in conventional systems, which can reduce the dwell time of the workpieces in the furnaces. This enables energy savings and a reduction in throughput times.
• the installation of a separating nozzle box additionally improves the degree of utilization of the system.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Thermal Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Mechanical Engineering (AREA)
• Physics & Mathematics (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Heat Treatment Of Strip Materials And Filament Materials (AREA)
• Mounting, Exchange, And Manufacturing Of Dies (AREA)
• Heat Treatments In General, Especially Conveying And Cooling (AREA)
• Furnace Details (AREA)

Applications Claiming Priority (5)

Publications (3)

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Country Status (4)

Family Cites Families (5)

• 2003
  • 2003-03-17 AU AU2003221601A patent/AU2003221601A1/en not_active Abandoned
  • 2003-03-17 AT AT03717150T patent/ATE302858T1/de active
  • 2003-03-17 WO PCT/DE2003/000864 patent/WO2003078665A2/fr not_active Ceased
  • 2003-03-17 EP EP03717150A patent/EP1490524B2/fr not_active Expired - Lifetime

Non-Patent Citations (1)

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