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
  • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
  • C21D9/0062—Heat-treating apparatus with a cooling or quenching zone
• • 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
  • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
  • C21D9/0037—Rotary furnaces with vertical axis; Furnaces with rotating floor
• • 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
  • C21D1/56—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering characterised by the quenching agents
  • C21D1/613—Gases; Liquefied or solidified normally gaseous material
• • 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

Definitions

• the invention relates to a continuous furnace with a device for quenching workpieces, the device being connected to a lock for removing the workpieces.
• the invention further relates to a method for quenching workpieces.
• the continuous furnace can be designed as a pusher furnace, roller hearth furnace or rotary hearth furnace.
• the workpieces are located on batch carriers during transport through the furnace, namely on grids or the like. In the furnace, the workpieces are exposed to a reaction gas, here endogas.
• the object of the invention is to develop a continuous furnace with a device for quenching and a method for quenching so that an energy-saving and environmentally friendly quenching of workpieces is made possible.
• the workpieces are quenched without having to accept the problems mentioned above when using liquid quenching agents. sen. Above all, there is no need to clean the workpieces of adhering oil, salt or water additives, which has environmental problems.
• Quenching with cooling gas has the advantage that the warpage of the quenched workpieces is small and also uniform.
• the quenching chamber has only one opening for loading and unloading.
• the quenching chamber is preferably arranged above the lock. This enables an essential further development of the invention, which consists in that the transport device is moved vertically with at least one spindle or similar device and that the transport device is designed such that it closes the opening between the lock and the quenching chamber during quenching.
• a transport floor is provided below the transport device for the horizontal transport of the workpieces through the lock when the quenching chamber is closed.
• the transport floor is preferably arranged at a fixed distance from the transport device.
• the quenching chamber is designed to be pressure-tight and provided with at least one circulation fan.
• the solution to the problem is that the workpieces in the lock are transported substantially vertically into a quenching chamber, in which the workpieces are quenched by means of recirculated cooling gas under increased pressure of less than 10 bar, and that after the quenching time the workpieces are put into the Lock transported and removed from this.
• Hydrogen is preferably used as the cooling gas.
• the cooling gas is advantageously flooded into a gas intermediate store.
• Fig. 1 a plan view of a rotary hearth furnace system in ring channel construction
• Fig. 2 a partial side section through the rotary hearth furnace with the device for quenching.
• the rotary hearth furnace system shown in FIGS. 1 and 2 is used for hardening workpieces 1, here gear parts.
• the gear parts 1 are stacked on batch carriers 2 (see FIG. 2), here on grates.
• the furnace system has a rotary hearth furnace 3 in a ring channel design, in which the workpieces 1 are heat-treated under a reaction gas, here endogas.
• An insulated oven door 4 is provided at one point for loading and unloading.
• a lock 5 adjoins the furnace door 4, which, as shown in FIG. 2, has an exit door 6.
• a quenching chamber 7 which is designed as a pressure chamber with a water-cooled outer jacket.
• the lock is provided with a transport device 8.
• the transport device 8 in the lock 5 can be moved vertically under the quenching chamber 7 by means of several spindles 9 or similar devices.
• the transport device is designed so that it has an opening 12 between it in a pressure-tight manner. see lock 5 and quench chamber 7 can close, for example via so-called finger pins, not shown.
• the quenching chamber 7 is connected to a pumping station 13 and a gas intermediate storage 14 for a cooling gas.
• a gas intermediate storage 14 for a cooling gas.
• circulation fans 10 the axes of which are arranged perpendicular or parallel to the axis of the quenching chamber 7 and which are driven by motors 11.
• a heat exchanger 15 shown in FIG. 2 cools the cooling gas while it is being circulated.
• a transport base 16 is arranged below the transport device 8 at a fixed distance from it, which, when the quenching chamber 7 is closed, enables the workpieces to be transported on the batch carriers under the quenching chamber.
• the spindles 9 or similar drives of the transport device 8 are arranged at four points laterally in the lock space 5, so that the lock can be passed through by a batch carrier.
• the spindles 9 are equipped with a radiation shield, not shown, as heat protection.
• the oven door 4 of the rotary hearth furnace 3 is opened and a batch carrier 2, for. B. encountered a grate from a known cross pusher on the transport device of the lock.
• the transport device 8 is at the same level as the hearth of the rotary hearth furnace. As soon as the cross pusher has passed through the furnace door, it can be lowered to a residual size that allows the cross pusher to return. After the cross pusher has left the lock, the transport device 8 is moved vertically under the quenching chamber 7. The transport device 8 closes the quenching chamber 7 in a gas-tight manner. While the workpieces are being transported, the reaction gas used in the continuous furnace is located in the quenching chamber as well as in the lock.
• the closed cold quenching chamber is pumped with a cooling gas, preferably hydrogen or Nitrogen, flooded and the workpieces quenched at a pressure of less than 10 bar, preferably 9.5 bar, by means of recirculating cooling gas.
• the hydrogen is flooded into the gas intermediate storage 14 and buffered after the cooling time has expired when the pressure is equalized to the furnace pressure.
• the cooling gas can be stored so that it can be used several times as a cooling gas so that it can finally be used for combustion purposes.
• the cooling gas could also be used to produce endogas for the continuous furnace or removed from the intermediate gas storage for heating purposes.
• the quenching chamber 7 is flushed with the reaction gas, here endogas. Then the transport device 8 is lowered and the workpieces 1 are transported from the quenching chamber 7 into the lock 5.
• the transport floor is in the position shown in dashed lines in FIG. 2.
• the exit door 6 of the lock 5 is provided with a burning gas curtain in a manner known per se. It can be opened early enough so that the transport device 8 arrives in the extension plane when the exit door 6 has reached its open position.
• a known grate extractor (not shown) can also move onto the transport device 8 and pull the grate 2 out of the lock.
• the workpieces 1 are fed via a discharge storage path 17 to a tempering furnace, not shown, to which a cooling section can be connected.
• the exit door 6 of the lock is closed and the lock 5 is flushed with endogas.
• the gas can be flushed into the intermediate gas storage 14.
• a torch (not shown) is used for flushing out during the flushing process.
• the workpieces quenched with cooling gas under pressure have only slight distortions, which are also uniform. It is not necessary to wash the workpieces. Due to the elevator principle, the flush volume is ring. When the lock exit door is open, only the reaction gas previously used in the furnace is in the lock.
• the quenching chamber can also be arranged below the lock.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Mechanical Engineering (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Tunnel Furnaces (AREA)
• Heat Treatments In General, Especially Conveying And Cooling (AREA)
• Furnace Charging Or Discharging (AREA)

Applications Claiming Priority (5)

Publications (2)

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Cited By (1)

Families Citing this family (2)

Family Cites Families (6)

• 2000
  • 2000-01-28 EP EP00909114A patent/EP1153146B1/fr not_active Expired - Lifetime
  • 2000-01-28 AT AT00909114T patent/ATE221923T1/de active
  • 2000-01-28 WO PCT/EP2000/000654 patent/WO2000044945A1/fr active IP Right Grant

Non-Patent Citations (1)

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