GB2197883A - Heat-treatment of metallic workpieces - Google Patents

Heat-treatment of metallic workpieces Download PDF

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Publication number
GB2197883A
GB2197883A GB08725907A GB8725907A GB2197883A GB 2197883 A GB2197883 A GB 2197883A GB 08725907 A GB08725907 A GB 08725907A GB 8725907 A GB8725907 A GB 8725907A GB 2197883 A GB2197883 A GB 2197883A
Authority
GB
United Kingdom
Prior art keywords
furnace
carburization
chambers
treatment
batches
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB08725907A
Other versions
GB8725907D0 (en
GB2197883B (en
Inventor
Hans Pfau
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ipsen International GmbH
Original Assignee
Ipsen International GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ipsen International GmbH filed Critical Ipsen International GmbH
Publication of GB8725907D0 publication Critical patent/GB8725907D0/en
Publication of GB2197883A publication Critical patent/GB2197883A/en
Application granted granted Critical
Publication of GB2197883B publication Critical patent/GB2197883B/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C8/06—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases
    • C23C8/08—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases only one element being applied
    • C23C8/20—Carburising
    • 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
    • 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
    • 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
    • F27B9/04—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity adapted for treating the charge in vacuum or special atmosphere
    • F27B9/045—Furnaces with controlled atmosphere
    • 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
    • F27B9/14—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity characterised by the path of the charge during treatment; characterised by the means by which the charge is moved during treatment
    • F27B9/16—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity characterised by the path of the charge during treatment; characterised by the means by which the charge is moved during treatment the charge moving in a circular or arcuate path

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Organic Chemistry (AREA)
  • Metallurgy (AREA)
  • Materials Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
  • Tunnel Furnaces (AREA)
  • Furnace Details (AREA)

Abstract

Apparatus for the heat-treatment of metallic workpieces in a carburization atmosphere comprises a carburization furnace (3), in which batches (1) of workpieces which may have been preheated in a heating furnace (2) arranged before the carburization furnace, are carburized at a constant temperature, with a constant carbon potential of the atmosphere at dwell times which vary according to the batch (1). A diffusion and hardening furnace (4) is arranged after the carburization furnace (3). In order that an individual treatment of the individual batches with different treatment parameters is possible, the diffusion and hardening furnace (4) comprises separate chambers (4 min , 4 sec , 4 sec min ) each for receiving a respective individual batch (1). The chambers (4 min , 4 sec , 4 sec min ) can be operated independently of and separately from one another at different temperatures and with different carbon potentials. The batches (1) can therefore be individually treated in the diffusion and hardening furnace (4). <IMAGE>

Description

HEAT-TREATMENT OF METALLIC WORKPIECES The present invention relates to apparatus for heat-treatment of metallic workpieces in a carburization atmosphere.
Such heat-treatment may be carried out in apparatus comprising a carburization furnace, in which batches of workpices, which may have been pre-heated in a heating furnace arranged before the carburization furnace, are carburized at a constant carburization temperature, with a constant carbon potential of the carburization atmosphere and dwell times which vary according to the batch, and a diffusion and hardening furnace arranged after the carburization furnace.
A gas carburization apparatus of this kind is described in UK-A-2 162 208 (DE-A-34 41 338). This apparatus comprises firstly a heating furnace, which is formed as a pusher-type furnace and in which the batches which are to be heat-treated are heated in a carburization-neutral, sootless atmosphere to a certain carburization temperature. This heating furnace is connected via a communicating door to a carburization furnace, which is formed as a rotary furnace. There is a constant carburization temperature and a constant carbon potential of the carburization atmosphere in this rotary furnace.The carburization process to which the batches transferred from the heating furnace, which is arranged before the carburization furnace, to the carburization furnace are subjected is determined by the dwell time of the individual batches in the carburization furnace, while the dwell time selected depends on the batch type. A diffusion furnace, which is also formed as a rotary furnace similar to the carburization furnace, is arranged after the carburization furnace. Finally, the diffusion furnace is followed by a soaking pit, which is formed as another pusher-type furnace. At the very end there is an oil quenching bath of the hardening chamber.
The disadvantage of the gas carburization apparatus as described for the heat-treatment of metallic workpieces lies in the fact that batch treatment can only be carried out at a constant temperature and with a constant carbon potential with the diffusion furnace which is formed as a rotary furnace. In the carburization furnace, the treatment process is entirely dependent on the dwell time of the individual batches in the diffusion furnace. Individual treatment of the batches at different temperatures and with different carbon levels is therefore impossible.
Taking the above as a basis, the object of the invention is to improve existing apparatus for heat-treatment of metallic workpieces such that an individual treatment of the individual batches with different treatment parameters is possible.
The present invention accordingly provides apparatus for heat-treatment of metallic workpieces in a carburization atmosphere comprising a carburization furnace for carburizing batches of workpieces at a constant carburization temperature, with a constant carbon potential of the carburization atmosphere and with dwell times which vary according to the batch, and a diffusion and hardening furnace arranged after the carburization furnace, the diffusion and hardening furnace comprising at least two chambers, which are separate from one another, each for receiving a respective individual batch, which chambers can be operated independently of and separately from one another at different temperatures and with different carbon potentials.
As the diffusion and hardening furnace is formed from a plurality of chambers, different parameters relating to temperature and carbon potential can be set for each batch. The batches from the carburization furnace can therefore be individually after-treated according to requirements at different temperatures and with different carbon levels, so that, in conjunction with the carburization furnace, which is preferably formed as a rotary furnace, optimum heat-treatment of the metallic workpieces in a carburization atmosphere is possible.
According to a preferred embodiment, three chambers are provided. These are preferably separated from one another by communicating doors. The three chamber design permits optimum after-treatment in the diffusion and hardening furnace. This means that a wide range of variations is possible and the diffusion and hardening temperature can be adapted to requirements in the best possible manner.
The cycle times in the individual chambers are preferably the same, so that the process is carried out in a highly regular manner in the diffusion and hardening furnace.
In another preferred embodiment of the invention at least one of the chambers is provided with a cooling system. This enables the temperature in the chamber to be individually adapted to the batch. It may, for example, be necessary to quickly reduce the temperature in one chamber for technological reasons, in which case the temperature variation can be between 50 and 1000C. In the case of certain carburization processes the workpiece temperature must be lowered to approximately 6000C, for which purpose a more powerful cooling system may also be provided in the chamber.
Finally, it is preferable to use a computer to control the operating sequences in the apparatus, so that any method for the heat-treatment of the metallic workpieces can be carried out automatically.
Further details and advantages will become apparent from the following description of the accompanying drawing, which shows in diagrammatic form apparatus according to the invention for the heat-treatment of metallic workpieces in a carburization atmosphere.
The illustrated apparatus for the heat-treatment of metallic workpieces in batches 1 comprises, when viewed in the direction of the transport path of the batches, a heating furnace 2 (represented by dot-dash lines), a carburization furnace 3 in the form of a rotary furnace, a diffusion and hardening furnace 4 and one or more after-treatment devices 5 (also represented by dot-dash lines).
A batch store, which is not shown, charges the heating furnace 2 with the batches 1 which are to be heat-treated. This charging operation may be carried out in a manner which is known per se by means of a pushing cylinder arrangement, which is not shown. The batches 1 are heated to carburization temperature in this heating furnace 2, i.e. to the temperature in the carburization furnace at which the batches 1 are to be heat-treated.
The carburization furnace 3 adjoins the heating furnace 2, with a communicating door 6 being arranged between the heating furnace 2 and the carburization furnace 3, and a pushing device 7, which is shown in diagrammatic form, pushes the batches 1 out of the heating furnace 3 and into the carburization furnace 3 after the communicating door 6 has been opened. As soon as a batch 1 of this kind has left the heating furnace 2 and entered the carburization furnace 3, a new batch 1 is fed into the heating furnace 2 from the batch store The carburization furnace 3 is formed as a so-called rotary furnace, i.e. the batches 1 are disposed on a continuously rotating rotary hearth 8 which can rotate about a central axis, as indicated by the arrow P. In the carburization furnace 3 there is a specific carburization atmosphere at a constant carburization temperature and with a constant carbon potential. The carburization process in the carburization furnace 3 is determined by the dwell time of the individual batches 1 in the carburization furnace 3, which can vary from batch to batch according to the metallic workpieces which are to be treated. The longer a batch 1 has to be treated, the longer it remains on the rotary hearth 8.
Once the carburization process has been completed, the rotary hearth 8 is rotated until the relevant batch 1 comes to a stop in front of the diffusion and hardening furnace 4, which is separated from the carburization furnace 3 by a communicating door 9. A pushing device 10 delivers the carburized batch 1 into the diffusion and hardening furnace 4.
As can be seen from the drawing, the diffusion and hardening furnace 4 consists of three chambers 4', 4", 4'n', which are arranged one after the other and separated from one another by communicating doors 11, 11'. Each of these chamebrs 4', 4??, 4??? can receive an individual batch 1. The chambers may also be operated separately from and independently of one another at different temperatures and with different carbon potentials, so that each individual batch may be treated individually in the diffusion and hardening furnace 4. The chambers 4', 4", 4 " ' are also provided with a cooling system, which is not shown. This means that it is also possible to vary the temperature in order to permit optimum adaptation to the respective requirements of individual batches. The sequence of operations in the apparatus can be controlled by means of a computer, and the batches 1 can pass through the three chambers 4', 4??, 4"' in a fixed cycle.
The after-treatment device 5 adjoins the diffusion and hardening furnace 4, from which it is separated by a communicating door 12. In accordance with common practice, this after-treatment device 5 may comprise an oil quenching bath, a cooling space, a washing machine and a drier. Finally, a store, which is not shown, for the treated batches 1 is arranged after the after-treatment device 5.

Claims (8)

1. Apparatus for heat-treatment of metallic workpieces in a carburization atmosphere comprising a carburization furnace for carburizing batches of workpieces at a constant carburization temperature, with a constant carbon potential of the carburization atmosphere and with dwell times which vary according to the batch, and a diffusion and hardening furnace arranged after the carburization furnace, the diffusion and hardening furnace comprising at least two chambers, which are separate from one another, each for receiving a respective individual batch, which chambers can be operated independently of and separately from one another at different temperatures and with different carbon potentials.
2. Apparatus according to claim 1, wherein three chambers are provided.
3. Apparatus according to claim 1 or 2, wherein the chambers are separated from one another by communicating doors.
4. Apparatus according to any one of the preceding claims, wherein the cycle times in the individual chambers are the same.
5. Apparatus according to any one of the preceding claims, wherein at least one of the chambers is provided with a cooling system.
6. Apparatus according to any one of the preceding claims, further comprising a computer control means for defining operating sequences of the apparatus.
7. Apparatus according to any one of the preceding claims, further comprising a heating furnace for pre-heating batches of workpieces before they enter the carburization furnace.
8. Apparatus for heat-treatment of metallic workpieces substantially as herein described with reference to the accompanying drawing.
GB8725907A 1986-11-26 1987-11-05 Heat-treatment of metallic workpieces Expired - Fee Related GB2197883B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE3640325A DE3640325C1 (en) 1986-11-26 1986-11-26 Device for the heat treatment of metallic workpieces in a carbonizing atmosphere

Publications (3)

Publication Number Publication Date
GB8725907D0 GB8725907D0 (en) 1987-12-09
GB2197883A true GB2197883A (en) 1988-06-02
GB2197883B GB2197883B (en) 1991-03-13

Family

ID=6314770

Family Applications (1)

Application Number Title Priority Date Filing Date
GB8725907A Expired - Fee Related GB2197883B (en) 1986-11-26 1987-11-05 Heat-treatment of metallic workpieces

Country Status (7)

Country Link
BE (1) BE1002059A4 (en)
DE (1) DE3640325C1 (en)
ES (1) ES2008313A6 (en)
FR (1) FR2607231B1 (en)
GB (1) GB2197883B (en)
IT (1) IT1222805B (en)
SE (1) SE501175C2 (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5665302A (en) * 1994-09-23 1997-09-09 Reynolds Wheels International Ltd. Method and equipment for bringing metal alloy ingots, billets and the like to the semisolid or semiliquid state in readiness for thixotropic forming
CN100434545C (en) * 2002-03-27 2008-11-19 洛伊热处理有限公司 Installation for the heat-treatment of parts
CN113981363A (en) * 2021-12-01 2022-01-28 浙江求精科技有限公司 Intelligent environment-friendly metal material heat treatment device and production process thereof

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4763880A (en) * 1987-04-03 1988-08-16 Holcroft/Loftus Inc. Rotary hearth multi-chamber, multi-purpose furnace system
JP3038992B2 (en) * 1991-06-19 2000-05-08 トヨタ自動車株式会社 Control method of carburizing furnace
DE4303686C2 (en) * 1992-10-07 1995-11-30 Iob Ind Ofen Bau Gmbh Furnace plant and method for the heat treatment of metallic workpieces

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1100072A (en) * 1965-04-01 1968-01-24 Kaiser Aluminium Chem Corp Improvements in or relating to the heat treatment of aluminium and its alloys

Family Cites Families (6)

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Publication number Priority date Publication date Assignee Title
FR2527641A1 (en) * 1982-05-28 1983-12-02 Air Liquide PROCESS FOR THERMALLY TREATING METALLIC PARTS THROUGH CARBURATION
GB2162208B (en) * 1984-07-20 1988-07-06 Ipsen Ind Int Gmbh Heat treatment of metal workpieces
DE3441338A1 (en) * 1984-11-13 1986-05-15 Ipsen Industries International Gmbh, 4190 Kleve Process for heat-treating metallic workpieces, using a straight-flow or continuous pusher-type furnace, and equipment for carrying out this process
DE3435376C2 (en) * 1984-09-27 1996-09-12 Loi Ipsen Holding Gmbh Process for heat treatment of workpieces
SE450389B (en) * 1984-10-02 1987-06-22 Volvo Ab METHOD AND PLANT FOR HEAT TREATMENT OF DETAILS WITH VARIOUS REQUIREMENTS FOR HEAT TREATMENT TIME
DE3506131C1 (en) * 1985-02-22 1986-05-22 Aichelin GmbH, 7015 Korntal-Münchingen Process for the heat treatment of in particular metallic workpieces and device for carrying out the process

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1100072A (en) * 1965-04-01 1968-01-24 Kaiser Aluminium Chem Corp Improvements in or relating to the heat treatment of aluminium and its alloys

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
WO A1 86/2104 *

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5665302A (en) * 1994-09-23 1997-09-09 Reynolds Wheels International Ltd. Method and equipment for bringing metal alloy ingots, billets and the like to the semisolid or semiliquid state in readiness for thixotropic forming
US5869811A (en) * 1994-09-23 1999-02-09 Reynolds Wheels International Ltd. Method and equipment for bringing metal alloy ingots, billets and the like to the semisolid or semiliquid state in readiness for thixotropic forming
CN100434545C (en) * 2002-03-27 2008-11-19 洛伊热处理有限公司 Installation for the heat-treatment of parts
CN113981363A (en) * 2021-12-01 2022-01-28 浙江求精科技有限公司 Intelligent environment-friendly metal material heat treatment device and production process thereof
CN113981363B (en) * 2021-12-01 2022-05-27 浙江求精科技有限公司 Intelligent environment-friendly metal material heat treatment device and production process thereof

Also Published As

Publication number Publication date
FR2607231B1 (en) 1990-08-17
SE8704663L (en) 1988-05-27
GB8725907D0 (en) 1987-12-09
BE1002059A4 (en) 1990-06-12
SE8704663D0 (en) 1987-11-25
GB2197883B (en) 1991-03-13
FR2607231A1 (en) 1988-05-27
IT1222805B (en) 1990-09-12
IT8722111A0 (en) 1987-10-02
DE3640325C1 (en) 1988-02-04
SE501175C2 (en) 1994-12-05
ES2008313A6 (en) 1989-07-16

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Legal Events

Date Code Title Description
PCNP Patent ceased through non-payment of renewal fee

Effective date: 19971105