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
• • 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
• • 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
  • C21D9/0006—Details, accessories not peculiar to any of the following furnaces
  • C21D9/0018—Details, accessories not peculiar to any of the following furnaces for charging, discharging or manipulation of charge
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F27—FURNACES; KILNS; OVENS; RETORTS
  • F27B—FURNACES, KILNS, OVENS OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
  • F27B9/00—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
  • F27B9/02—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity of multiple-track type; of multiple-chamber type; Combinations of furnaces
  • F27B9/028—Multi-chamber type furnaces

Definitions

• the invention relates to a device for the heat treatment of metallic workpieces, with a plurality of furnace modules which can be exposed to a protective gas atmosphere and are connected to one another via at least one intermediate transfer lock which can be subjected to protective gas, and the intermediate transfer locks a transport device for transporting the grids having.
• Such a device is known from EP 0 209 408 AI.
• the known device has a low-temperature furnace module, a high-temperature furnace module and an intermediate transfer lock in order to be able to transport workpieces under a protective gas atmosphere between the individual modules.
• the known device can be used very flexibly, since the gas atmosphere, treatment duration and temperature can be selected individually in the individual modules, but is only suitable for small throughputs.
• a device for the heat treatment of metallic workpieces which has at least two furnace modules, of which at least one furnace module has a plurality of individual chambers, each of which can be closed via gas-tight doors .
• At least one intermediate transfer lock is provided for transport between the individual oven modules, which enables the workpieces to be transported under an inert gas atmosphere.
• a modular arrangement of the furnace units into individual chambers, each of which can be individually controlled, results in a particularly high flexibility of the system, however such a system can only be used for small to medium throughputs.
• the invention is therefore based on the object of providing a device for the heat treatment of metallic workpieces which guarantees the greatest possible flexibility and is also suitable for higher throughputs.
• At least one furnace module is designed as a push-through furnace module with grids for the transport of workpieces.
• a plurality of furnace modules which can be exposed to a protective gas atmosphere are connected to one another via at least one intermediate transfer lock which can be subjected to a protective gas atmosphere, and at least one furnace module is designed as a push-through furnace module with grids for transporting the workpieces.
• This configuration of at least one furnace module, preferably all furnace modules, as a push-through furnace module enables a significantly higher throughput of the overall system to be achieved, while a high degree of flexibility is ensured as a result of the transport between the individual furnace modules via a protective gas-charged intermediate transfer lock.
• the intermediate transfer lock is coupled to at least one vacuum inlet lock for loading workpieces.
• each individual oven module can be quickly loaded via the at least one intermediate transfer lock, and there is also the possibility of quickly removing repair batches.
• the intermediate transfer lock has at least one grate transport carriage with a gas-tight drive.
• This measure has the advantage that a largely wear-free transport of the grids between the individual furnace modules is possible under protective gas.
• the drive can be designed as a positionable drag chain circulating drive.
• the intermediate transfer lock is designed as an unheated, heat-insulated lock tunnel.
• heating of the intermediate transfer lock can be dispensed with, while the workpieces can be transported between the individual furnace modules under protective gas without excessive heat loss.
• a cross-joint device for loading and unloading is provided in front of at least one oven module, preferably in front of each oven module.
• the individual batches can easily be moved from the grate transport trolley out of the intermediate transfer lock Are moved into the individual oven modules or are moved from the oven modules onto a further grate transport carriage to another oven module or to another unit.
• At least one furnace module has a plurality of individual chambers, which can each be closed by means of gas-tight doors, the temperature, dwell time and atmosphere being freely selectable.
• This measure has the advantage that different heat treatments can be carried out in succession in the furnace module divided into several individual chambers without first having to be transported to another furnace module. Rather, the sliding transport of the grates from single chamber to single chamber ensures quick transport.
• At least one oven module has two slides arranged below the grids, which are supported on one another, the upper slider being able to be raised relative to the lower slider in order to lift the grids off the furnace floor, and the two slides in the raised position are displaceable together for the sport of the gratings.
• variable module cycle times are possible within a wide range for each furnace module, and even multiple passes through a furnace module are made possible via the intermediate transfer lock, practically all conceivable case hardening depths can be achieved and at the same time run in the overall system.
• a variable furnace occupancy can be achieved in each furnace module, which further increases the flexibility of the overall system.
• a grate transport carriage with a gas-tight drive for example a drag chain circulating drive
• a lifting furnace conveyor can also be provided within the intermediate transfer lock the aforementioned manner.
• support elements are provided between the two slides of the lifting furnace conveyor, which enable a combined movement of at least the upper slider in the horizontal direction and in the vertical direction.
• the support elements are designed as mutually parallel inclined planes of the upper slide or lower slide.
• This measure has the advantage that the transport mechanism is extremely simple, since only a translational movement is required in order to raise and lower the upper slide relative to the lower slide and to move both slides and thus the grids forward.
• inclined planes as support elements, there is frictional contact of the guide surfaces with a relative movement of the slide, but the frictional forces are limited to the guide surfaces, which can be designed accordingly.
• the grates themselves are moved largely wear-free against the furnace floor.
• the throughput time of at least one oven module is variable independently of the other oven modules.
• variable module cycle times of ten, twenty, thirty, forty and sixty minutes can be provided for each furnace module.
• various possible uses can be achieved, namely one use as a single-purpose system with, for example, a single case depth but with a very high total throughput, or use as a multi-purpose system, for example at the same time with different case hardnesses, and finally also as a multi-purpose system, for example when driving with more than three different ones Case hardening depths and various hardening and tempering processes with short throughputs.
• FIG. 1 shows an exemplary embodiment of the device according to the invention in a schematic representation
• Fig. 3 shows the grate transport drive according to FIG. 2 after moving the upper slide and lifting the grids.
• a device according to the invention is generally designated by the number 10 in FIG. 1.
• the device 10 has a total of five furnace modules, all of which are designed as push-through furnace modules.
• the first furnace module 12 and the second furnace module 14 are provided, for example, for heating and carburizing, while the third furnace module 16 and the fourth furnace module 18 are used for carburizing and the fifth furnace module 20 can be used for the final diffusion.
• the individual furnace modules 12, 14, 16, 18, 20 are connected to one another via an intermediate transfer lock 22, in which the workpieces 26 or the grids 24 can be transported under a protective gas atmosphere. All of the furnace modules 12, 14, 16, 18, 20 and the intermediate transfer lock 22 are therefore largely gas-tight in order to enable treatment or transport under protective gas. It goes without saying that treatment or transport under vacuum could of course also be provided in an alternative manner, provided that this is advantageous in individual cases.
• the loading takes place via a loading trolley 54 through a connecting channel 56 via a vacuum inlet lock 30, from which the grids 24 reach the intermediate transfer lock 22 via a transverse pushing device 58.
• a transport device 28 with a plurality of grate transport carriages 32 can be moved and positioned as desired via a drag chain circulating drive. It goes without saying that any other types of drive for transporting the grids 24 can also be provided within the intermediate transfer lock 22, provided that these meet the respective requirements.
• transverse push devices 58 are respectively provided, which are indicated only schematically with their transverse impact drive 59.
• the first four oven modules 12 to 18 can each accommodate nine grids 24 in a row, while the fifth oven module 20 can hold one grate in its first single chamber 19 and two grids in its second single chamber 21.
• the furnace modules 12 to 20 are each connected via gas-tight doors 60 to the intermediate transfer lock 28 or the upstream vacuum inlet lock 30 or the downstream immersion oil quenching bath 34.
• the two individual chambers 19, 21 of the fifth furnace module 20 are separated from one another via a gas-tight door 62, so that the temperature, gas atmosphere and, within certain limits, the dwell time of the workpieces in both individual chambers 19, 21 can be freely selected.
• immersion oil quenching bath 34 is followed by a cleaning system 36.
• the intermediate transfer lock 22 is designed as an unheated, heat-insulated lock tunnel, so that the workpieces can be transported without major heat losses within the intermediate transfer lock 22 without additional heating of the intermediate transfer lock 22.
• a buffer memory 64 is also provided for holding workpieces before or after the heat treatment.
• a lifting furnace conveyor device according to DE 41 32 197 A1 is provided for transporting the grids 24 within the first four furnace modules 12 to 18, to which express reference is made here with regard to details of the drive.
• FIGS. 2 and 3 are provided only for the purpose of a basic explanation of this transport device 38. While the gratings 24 are placed on the furnace floor 44 in the basic position according to FIG. 2, they are lifted off the furnace floor 44 according to FIG. 3 for advancement.
• the transport device 38 has a lower slide 40 and an upper slide 42, which are arranged below the grids 24 and wherein the upper slide 42 is supported on the lower slide 40.
• FIGS. 2 and 3 parallel guide surfaces in the form of inclined planes 46, 48 are provided on the lower slide 40 and on the upper slide 42.
• the inclined planes 46, 48 are connected by bearing surfaces 50, 52 of the upper slide 42 and of the lower slide 40 parallel to the furnace floor 44, so that both slides 40, 42 have a sawtooth shape in longitudinal section according to FIGS.
• the upper slide 42 and the lower slide 40 are divided into individual modules which are arranged one behind the other in the transport direction 54.
• FIG. 2 shows the basic position in which the two slides 40, 42 lie flat on one another and the grids 24 are on the furnace floor 44.
• the device according to the invention is subordinated to a charging cycle of ten minutes on the loading and unloading side.
• Variable module cycle times can be set in each case within the oven modules 12 to 20, specifically ten, twenty, thirty, forty and sixty minutes.
• connection of the individual oven modules 12 to 20 via the gas-tight intermediate transfer lock 22 also enables the first four oven modules 12 to 18 to be run through several times. Furthermore, a variable furnace occupancy between zero and nine grids per furnace module is possible within the first four furnace modules 12 to 18 per loading cycle.
• furnace modules can also be at least partially put out of operation in order to enable economical operation of the device according to the invention even with reduced throughput.
• a high throughput can also be achieved with flexibility of the device according to the invention.
• the device according to the invention can thus advantageously also be used in large-scale production.
• FIG. 1 shows only one possible of many alternatives, and that the system can be varied as desired with regard to the structure and the number of individual oven modules, that other additional components, such as quenching baths and the like, are used can be that further intermediate transfer locks can be provided, that additional inlet transfer locks or also further vacuum inlet locks can be provided.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• General Engineering & Computer Science (AREA)
• Tunnel Furnaces (AREA)
• Heat Treatment Of Strip Materials And Filament Materials (AREA)

Applications Claiming Priority (3)

Publications (2)

Family

ID=6488525

Family Applications (1)

Country Status (4)

Families Citing this family (5)

Family Cites Families (9)

• 1993
  • 1993-05-19 DE DE4316841A patent/DE4316841A1/de not_active Withdrawn
• 1994
  • 1994-05-12 EP EP94917626A patent/EP0699243B1/fr not_active Expired - Lifetime
  • 1994-05-12 AT AT94917626T patent/ATE152183T1/de not_active IP Right Cessation
  • 1994-05-12 DE DE59402542T patent/DE59402542D1/de not_active Expired - Fee Related
  • 1994-05-12 WO PCT/EP1994/001539 patent/WO1994026940A1/fr not_active Ceased

Non-Patent Citations (1)

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