EP0198871A1 - Method and installation for heat treatment, especially case-hardening. - Google Patents

Method and installation for heat treatment, especially case-hardening.

Info

Publication number
EP0198871A1
EP0198871A1 EP19850905124 EP85905124A EP0198871A1 EP 0198871 A1 EP0198871 A1 EP 0198871A1 EP 19850905124 EP19850905124 EP 19850905124 EP 85905124 A EP85905124 A EP 85905124A EP 0198871 A1 EP0198871 A1 EP 0198871A1
Authority
EP
European Patent Office
Prior art keywords
furnace
heat treatment
articles
installation
ring
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
EP19850905124
Other languages
German (de)
French (fr)
Other versions
EP0198871B1 (en
Inventor
Tomas Barkman
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.)
Volvo AB
Original Assignee
Volvo AB
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
Family has litigation
First worldwide family litigation filed litigation Critical https://patents.darts-ip.com/?family=20357207&utm_source=google_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=EP0198871(A1) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.
Application filed by Volvo AB filed Critical Volvo AB
Priority to AT85905124T priority Critical patent/ATE39949T1/en
Publication of EP0198871A1 publication Critical patent/EP0198871A1/en
Application granted granted Critical
Publication of EP0198871B1 publication Critical patent/EP0198871B1/en
Expired legal-status Critical Current

Links

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
    • 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

Definitions

  • the present invention relates to a method of heat treatment, especially case-hardening, of articles with varying requirements as to heat treatment time.
  • the invention also relates to a heat treatment instal- lation particularly suited to carrying out said method,
  • continuous case hardening up to now pusher type installations have been used, in which the articles to be hardened are placed on metal skidding pallets, which are inserted through a feed-in opening at one end of the heat treatment furnace, and after heat treatment has been completed, are taken out through an exit opening at the opposite end of the furnace.
  • the articles are heated to the heat treatment temperature and kept at this temperature as long as is required to achieve the desired carbonization depth.
  • the method is based on the principle: first in - first out, and presupposes that all the articles inserted at the same time into the furnace are to have the same carbonization depth and therefore the same heat treatment time. If the assortment of articles in the heat treatment installa ⁇ tion contains articles requiring different carboniza ⁇ tion depths, which is often the case, these cannot be mixed in the furnace, since those articles requiring a short heat treatment time cannot be taken out before those requiring a longer treatment time. The result will be low utilization of capacity, when a few articles are to have a long heat treatment time and the available furnace space cannot at the same time be used for articles requiring a shorter treatment time.
  • the purpose of the present invention is to achieve a method which makes it possible to better utilize available capacity by making it possible to treat at the same time articles which are to have differing carbonization depths.
  • An installation particularly suited to carrying out the method according to the invention comprises a ring furnace known per se with a rotatable carrier for the articles and is characterized in that the discharge opening from a separate heating-up furnace is connected directly to the input opening of the ring furnace.
  • all the articles are heated in the heating-up furnace to the heat treatment temperature of the heat treatment furnace.
  • the articles to be heat-treated for 1.5 hours can be inserted into the heat treatment furnace after the articles to be treated for 3.5 hours, and be taken out before these, without requiring a change in the temperature or atmosphere of the heat treatment furnace.
  • a ring furnace this can be done quite simply.
  • Each article is time-monitored, preferably via a computer system, and is advanced to the exit point from the ring furnace after heat treatment has been completed.
  • 1 designates a feeding station for articles to be case-hardened.
  • the articles are placed on metal skidding pallets 2, on which the artic ⁇ les are then transported through the installation.
  • the pallets are transferred to a conveyor 4 and are conveyed thereon through a washing station 5 and back to the conveyor 3 via a conveyor 6, and from there to a conveyor 7, by means of which the skidding pallets 2 are fed into the heat treatment furnace 8.
  • the pallets are advanced to a heating up furnace 9, in which the articles are heated up to their heat treatment temperature, e.g. ca 900°C.
  • the heating-up furnace 9 is attached directly to a ring furnace 10, in which the pallets after heat ⁇ ing of the articles are placed on a turn-table (as is indicated by the arrows in the figure). Regardless of the order in which the pallets are fed into the furnace 10, anyone of the pallets can now be removed by virtue of the fact that the turn-table can be advanced as many steps as are desired in either direction in order to place the selected pallet at the outlet 11 of the furnace 10. .
  • the articles After treatment has been completed in the ring furnace 10, the articles are.transferred to a diffusion furnace 12 and from there either directly to a packing robot 13 or to an oil bath 14. From the oil bath 14, the articles are conveyed via conveyors 3 and 4 once again through the washing station 5 and finally to a tempering furnace 15, from which the articles are conveyed out to the conveyor 3»
  • the heat treatment installation shown and described is suitably controlled by a computerized control system which keeps track of where each indi ⁇ vidual pallet is at each moment and times the various operations, so that all of the articles receive the proper heat treatment period independently of the order in which they are fed into the installation.

Landscapes

  • 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)
  • Heat Treatment Of Articles (AREA)
  • Heat Treatments In General, Especially Conveying And Cooling (AREA)

Abstract

Un procédé et une installation sont utilisés pour des traitements thermiques associés à la cémentation d'objets nécessitant des temps de traitement thermique divers. Les objets sont premièrement chauffés dans un four de préchauffage (9) jusqu'à la température requise pour le traitement thermique. Ils reçoivent ensuite un traitement thermique dans un four annulaire (10). Les objets sont retirés du four annulaire après un temps de retenue prédéterminé, indépendamment de l'ordre dans lequel ils ont été introduits, en faisant avancer chaque objet jusqu'à l'ouverture de décharge (11) du four.A method and an installation are used for heat treatments associated with the case hardening of objects requiring various heat treatment times. The objects are first heated in a preheating oven (9) to the temperature required for the heat treatment. They then receive a heat treatment in an annular oven (10). The objects are removed from the annular oven after a predetermined holding time, regardless of the order in which they were introduced, advancing each object to the discharge opening (11) of the oven.

Description

Method and installation for heat treatment, especially case-hardening
The present invention relates to a method of heat treatment, especially case-hardening, of articles with varying requirements as to heat treatment time. The invention also relates to a heat treatment instal- lation particularly suited to carrying out said method, In continuous case hardening, up to now pusher type installations have been used, in which the articles to be hardened are placed on metal skidding pallets, which are inserted through a feed-in opening at one end of the heat treatment furnace, and after heat treatment has been completed, are taken out through an exit opening at the opposite end of the furnace. In the furnace, the articles are heated to the heat treatment temperature and kept at this temperature as long as is required to achieve the desired carbonization depth. The method is based on the principle: first in - first out, and presupposes that all the articles inserted at the same time into the furnace are to have the same carbonization depth and therefore the same heat treatment time. If the assortment of articles in the heat treatment installa¬ tion contains articles requiring different carboniza¬ tion depths, which is often the case, these cannot be mixed in the furnace, since those articles requiring a short heat treatment time cannot be taken out before those requiring a longer treatment time. The result will be low utilization of capacity, when a few articles are to have a long heat treatment time and the available furnace space cannot at the same time be used for articles requiring a shorter treatment time. The purpose of the present invention is to achieve a method which makes it possible to better utilize available capacity by making it possible to treat at the same time articles which are to have differing carbonization depths.
This is achieved according to the invention by a plurality of articles being heated up at the same time in a separate heating-up furnace to a predeter- mined temperature, the articles being thereafter inserted into and kept in a heat treatment furnace for heat treatment, the holding time for each article in the heat treatment furnace being monitored individu¬ ally and the articles being removed individually from the furnace after a predetermined holding time independently of the sequence of insertion.
An installation particularly suited to carrying out the method according to the invention comprises a ring furnace known per se with a rotatable carrier for the articles and is characterized in that the discharge opening from a separate heating-up furnace is connected directly to the input opening of the ring furnace.
In the method according to the invention, all the articles are heated in the heating-up furnace to the heat treatment temperature of the heat treatment furnace. The articles to be heat-treated for 1.5 hours, for example, can be inserted into the heat treatment furnace after the articles to be treated for 3.5 hours, and be taken out before these, without requiring a change in the temperature or atmosphere of the heat treatment furnace. By using a ring furnace, this can be done quite simply. Each article is time-monitored, preferably via a computer system, and is advanced to the exit point from the ring furnace after heat treatment has been completed.
The invention will be described in more detail with reference to an example shown in the accompanying drawing, which shows schematically a heat treatment installation, particularly suited for carrying out the method according to the invention.
In the figure, 1 designates a feeding station for articles to be case-hardened. The articles are placed on metal skidding pallets 2, on which the artic¬ les are then transported through the installation. From a conveyor 3 , the pallets are transferred to a conveyor 4 and are conveyed thereon through a washing station 5 and back to the conveyor 3 via a conveyor 6, and from there to a conveyor 7, by means of which the skidding pallets 2 are fed into the heat treatment furnace 8. After preheating, the pallets are advanced to a heating up furnace 9, in which the articles are heated up to their heat treatment temperature, e.g. ca 900°C.
The heating-up furnace 9 is attached directly to a ring furnace 10, in which the pallets after heat¬ ing of the articles are placed on a turn-table (as is indicated by the arrows in the figure). Regardless of the order in which the pallets are fed into the furnace 10, anyone of the pallets can now be removed by virtue of the fact that the turn-table can be advanced as many steps as are desired in either direction in order to place the selected pallet at the outlet 11 of the furnace 10. .
After treatment has been completed in the ring furnace 10, the articles are.transferred to a diffusion furnace 12 and from there either directly to a packing robot 13 or to an oil bath 14. From the oil bath 14, the articles are conveyed via conveyors 3 and 4 once again through the washing station 5 and finally to a tempering furnace 15, from which the articles are conveyed out to the conveyor 3»
The heat treatment installation shown and described is suitably controlled by a computerized control system which keeps track of where each indi¬ vidual pallet is at each moment and times the various operations, so that all of the articles receive the proper heat treatment period independently of the order in which they are fed into the installation.

Claims

1. Method of heat treatment, preferably case- hardening, of articles with varying requirements as to heat treatment time, characterized in that a plurality of articles are heated up at the same time in a separate heating-up furnace (9) to a predetermined temperature, that the articles are thereafter inserted into and kept in a heat treatment furnace (10) for heat treatment, that the holding time for each article in the heat treatment furnace is monitored individually and that the articles are removed individually from the furnace after a predetermined holding time independently of the sequence of insertion.
2. Method according to Claim 1, characterized in that the articles after heating up are placed on a rotary carrier in a ring furnace (10) and that each article, when the predetermined holding time has expired, is advanced to a discharge opening in the furnace by rotation of the carrier.
3. Method according to Claim 2, characterized in that the articles, after heat treatment in the ring furnace (10), are fed into a diffusion furnace (12) directly connected to the ring furnace.
4. Installation for heat treatment, preferably case-hardening, of articles with varying requirements as to heating-up time, said installation comprising a ring furnace with a rotary carrier for the articles, characterized in that the discharge opening from a heating-up furnace (9) is directly connected to the feeding opening of the ring furnace (10).
5. Installation according to Claim 4, characterized in that the ring furnace has a discharge opening (11) placed diametrically opposite to its feed-in opening and is directly connected to the feed-in opening of a diffusion furnace (12).
EP19850905124 1984-10-02 1985-09-30 Method and installation for heat treatment, especially case-hardening Expired EP0198871B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT85905124T ATE39949T1 (en) 1984-10-02 1985-09-30 METHOD AND DEVICE FOR HEAT TREATMENT, ESPECIALLY FOR CASE HARDENING.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
SE8404926 1984-10-02
SE8404926A SE450389B (en) 1984-10-02 1984-10-02 METHOD AND PLANT FOR HEAT TREATMENT OF DETAILS WITH VARIOUS REQUIREMENTS FOR HEAT TREATMENT TIME

Publications (2)

Publication Number Publication Date
EP0198871A1 true EP0198871A1 (en) 1986-10-29
EP0198871B1 EP0198871B1 (en) 1989-01-11

Family

ID=20357207

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19850905124 Expired EP0198871B1 (en) 1984-10-02 1985-09-30 Method and installation for heat treatment, especially case-hardening

Country Status (5)

Country Link
EP (1) EP0198871B1 (en)
JP (1) JPS62500529A (en)
DE (1) DE3567479D1 (en)
SE (1) SE450389B (en)
WO (1) WO1986002104A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0735149A1 (en) * 1995-03-31 1996-10-02 Ipsen Industries International Gesellschaft Mit Beschränkter Haftung Device for the vacuum heat treatment of metallic articles
WO1998008988A1 (en) * 1996-08-30 1998-03-05 Franz Hillingrathner Revolving furnace for the treatment of work pieces

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
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
DE3640325C1 (en) * 1986-11-26 1988-02-04 Ipsen Ind Internat Gmbh Device for the heat treatment of metallic workpieces in a carbonizing atmosphere
US5187670A (en) * 1990-11-05 1993-02-16 Caterpillar Inc. Control system for scheduling parts in a heat-treating process
DE19635257C1 (en) * 1996-08-30 1998-03-12 Franz Hillingrathner Compact orbital heat treatment furnace
EP2186916B1 (en) 2008-11-17 2013-10-02 LOI Thermprocess GmbH Process and installation for continuous case hardening

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2013905A (en) * 1933-02-04 1935-09-10 Jr James L Adams Circular ingot heating furnace
DE971225C (en) * 1943-10-13 1958-12-31 Aeg Rotary hearth furnace with attached cooling chamber
DE1201380B (en) * 1958-05-07 1965-09-23 Lee Wilson Method and device for the heat treatment of loosened metal tape reels
US3112918A (en) * 1961-03-28 1963-12-03 Salem Brosius Inc Rotary hearth furnace control
CA980040A (en) * 1971-09-07 1975-12-16 John P. Stallings Homogeneously colored low profile unsaturated polyester moldings and preparations thereof
US3779697A (en) * 1972-02-28 1973-12-18 Morgan Construction Co Means and method of heating and handling large coiled billet rod for metal rolling
JPS58217625A (en) * 1982-06-09 1983-12-17 Daido Steel Co Ltd Heat treating apparatus

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO8602104A1 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0735149A1 (en) * 1995-03-31 1996-10-02 Ipsen Industries International Gesellschaft Mit Beschränkter Haftung Device for the vacuum heat treatment of metallic articles
WO1998008988A1 (en) * 1996-08-30 1998-03-05 Franz Hillingrathner Revolving furnace for the treatment of work pieces

Also Published As

Publication number Publication date
EP0198871B1 (en) 1989-01-11
SE8404926D0 (en) 1984-10-02
JPS62500529A (en) 1987-03-05
SE8404926L (en) 1986-04-03
WO1986002104A1 (en) 1986-04-10
SE450389B (en) 1987-06-22
DE3567479D1 (en) 1989-02-16

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