EP0213991A1 - Beschleunigtes Karburierungsverfahren in einem kontinuierlichen Ofen - Google Patents

Beschleunigtes Karburierungsverfahren in einem kontinuierlichen Ofen Download PDF

Info

Publication number
EP0213991A1
EP0213991A1 EP86401584A EP86401584A EP0213991A1 EP 0213991 A1 EP0213991 A1 EP 0213991A1 EP 86401584 A EP86401584 A EP 86401584A EP 86401584 A EP86401584 A EP 86401584A EP 0213991 A1 EP0213991 A1 EP 0213991A1
Authority
EP
European Patent Office
Prior art keywords
concentration
atmosphere
carbon monoxide
continuous
furnace
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
EP86401584A
Other languages
English (en)
French (fr)
Other versions
EP0213991B1 (de
Inventor
Philippe Queille
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.)
Air Liquide SA
LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
Original Assignee
Air Liquide SA
LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude
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=9322228&utm_source=google_patent&utm_medium=platform_link&utm_campaign=public_patent_search&patent=EP0213991(A1) "Global patent litigation dataset” by Darts-ip is licensed under a Creative Commons Attribution 4.0 International License.
Application filed by Air Liquide SA, LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude filed Critical Air Liquide SA
Priority to AT86401584T priority Critical patent/ATE40416T1/de
Publication of EP0213991A1 publication Critical patent/EP0213991A1/de
Application granted granted Critical
Publication of EP0213991B1 publication Critical patent/EP0213991B1/de
Expired legal-status Critical Current

Links

Images

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
    • C23C8/22—Carburising of ferrous surfaces

Definitions

  • the present invention relates to a rapid case-hardening process in a continuous closed furnace into which a carrier gas and optionally a hydrocarbon are injected capable of generating, at the usual case-hardening temperatures, an atmosphere of predetermined composition, having a nominal concentration of carbon monoxide, an oven door being opened with a determined periodicity to allow the passage of a charge to be cemented, the opening of this door generating in particular an increase in the concentration of oxidizing species in the atmosphere of said oven.
  • a continuous closed furnace is a furnace into which are introduced at regular time intervals the charges to be treated which advance at low speed therein, successively passing through a zone of temperature rise of the charges, a zone of case-hardening of the pieces of the charge and a diffusion zone of said coins.
  • a continuous closed oven may have entry and exit airlocks which partially decrease the increase in the concentration of oxidizing species in the atmosphere and may also have non-watertight separation doors between each zone.
  • This atmosphere consists of:
  • the method according to the invention makes it possible to avoid these drawbacks. It is characterized in that the carbon monoxide concentration of the atmosphere injected into the furnace is increased with the same periodicity, so as to compensate for the increase in the concentration of oxidizing species in the furnace and thus maintain substantially constant the carbon potential of the furnace carburizing atmosphere throughout the carburizing duration of said parts. If carbon monoxide is formed in the furnace after cracking of one of the source elements of the carrier gas, the increase in concentration of carbon monoxide is understood as the correlative increase in the generator element.
  • the carrier gas comprises nitrogen and an alcohol, preferably methanol (or ethanol).
  • the increase in concentration of carbon monoxide signifies in this case a corresponding increase in the concentration of methanol in the carrier gas.
  • the carbon monoxide concentration in the atmosphere is increased, so as to compensate for the increase in carbon dioxide in order to maintain a substantially constant carbon potential.
  • this increase in carbon monoxide concentration will preferably be accompanied by an increase in the flow rate of the carrier gas.
  • a carrier gas flow rate of 1.5 to 4 times the "nominal" carrier gas flow rate, corresponding to the charge treatment phase (case hardening and / or diffusion), will preferably be used.
  • the oven door will be closed before the injection of carrier gas with a high concentration of carbon monoxide begins.
  • a carrier gas economy is achieved since when the door is open, the increase in the concentration of oxidizing species cannot be avoided.
  • the opening of the oven door will be preceded for a few moments by an injection of carrier gas with a high concentration of carbon monoxide, this injection continuing at least until the door is closed. and possibly after closing thereof, under conditions of duration specified below.
  • the carbon monoxide boost can be timed when the cycle is programmed. Thus it is easy to provide a time delay after closing the door, before returning to the "nominal" carbon monoxide flow. Likewise, provision may be made for a pre-triggering of the carbon monoxide supercharging synchronized with the opening of the door.
  • the injection of carrier gas with a high concentration of carbon monoxide may or may not be accompanied by an increase in the flow rate of carrier gas, preferably within the limits mentioned above.
  • the duration of the injection of carrier gas having a concentration of carbon monoxide greater than the nominal value will be between 5% and 50% of the total duration of the treatment.
  • the carrier gas with a carbon monoxide concentration greater than the nominal value will preferably be obtained from a nitrogen-methanol mixture, with a volume ratio such as 1/20 ⁇ R1 ⁇ 3/7
  • the carrier gas with a carbon monoxide concentration equal to the nominal value will also be obtained from a nitrogen-methanol mixture in a volume ratio preferably having the value
  • a load consisting of steel parts to be cemented is introduced every few minutes (generally from 4 to 20 minutes).
  • This oven generally comprises successively an entry door, an entry airlock, a carburizing zone and a diffusion zone, possibly separated by doors, an exit airlock with quenching tank.
  • the atmosphere generated in the furnace is of the "endothermic" type, that is to say rich mainly in hydrogen, carbon monoxide and nitrogen species, obtained from a generator, or nitrogen and bodies intended for create in the oven the CO and H 2 species which may be methanol alone (preferred solution), ethanol-oxidant mixtures (H 2 0, Air, 00 2, etc.) or equivalent, to which up to 10% may be added of hydrocarbon (CH 4 , C 3 H 8 7) to control the carbon potential and sometimes up to 5% of ammonia for specific treatments such as carbonitriding (cementation activated with ammonia).
  • endothermic that is to say rich mainly in hydrogen, carbon monoxide and nitrogen species, obtained from a generator, or nitrogen and bodies intended for create in the oven the CO and H 2 species which may be methanol alone (preferred solution), ethanol-oxidant mixtures (H 2 0, Air, 00 2, etc.) or equivalent, to which up to 10% may be added of hydrocarbon (CH 4 , C 3 H 8 ...) to control the carbon potential and
  • the entry door is opened, which causes significant uncontrolled entries of oxidizing species (0 2 or CO 2 , H 2 0, resulting from the combustion of the atmosphere of the oven with the outside air).
  • the concentration of carbon monoxide can be considered constant during the whole process. Consequently, the carbon potential varies very strongly in the carburizing zone of the furnace, according to the curve C 1 illustrated in FIG. 5. It can decrease up to a PC M value of the order of 0.1 to 0.3 % for a case-hardening temperature of 920 ° C for example. (The setpoint for the carbon potential at this temperature is often in the range of 0.8 to 1.0%). Reconditioning the oven to the set value takes practically the entire time interval to to t 1 between two successive introductions.
  • FIG. 2 by way of indication represents the flow rate of carrier gas injected into the furnace according to the known solution of the American patent cited above, this flow rate normally having the value DL when the door is closed, and a value DH when the door of the furnace is open, substantially equal to 2 times DL or more.
  • the concentration of carbon monoxide in the atmosphere injected into the oven is increased during the charging of a new charge (or during the diversion, if the latter causes a disturbance similar) or little time previously so as to anticipate the increase in concentration of oxidizing species, without reaching a carbon activity of the atmosphere equal to 1, which would generate soot on the parts.
  • This increase in concentration is generally carried out during the entire duration of the opening of the oven door. It generally continues after the closing of this door in order to return more quickly to the set carbon potential.
  • This measure is doubly favorable because it allows, on the one hand, to maintain the carbon potential of the atmosphere at a sufficient value for there to be carbon transfer from the atmosphere in the room but it also allows other part to accelerate this transfer to the part, since the carbon transfer speed depends, in the carburizing phase, on the product pH 2 x pCo, which are the respective partial pressures of H 2 and CO in the furnace (here equal to concentrations).
  • This increase in carbon monoxide concentration is effected by injection into the furnace of carbon monoxide or, preferably, of a product liable to decompose, in the atmosphere of the furnace to generate this carbon monoxide.
  • the atmosphere injected into the oven is either that of an endo generator at constant flow rate, or preferably, a nitrogen / methanol mixture or equivalent as described above.
  • the injection is increased, during the time ⁇ t ', of carbon monoxide whose concentration increases from [CO] 1 (which is generally of the order of 20 % by volume) to [CO] 2 (which is around 27% by volume).
  • the simplest method for implementing the invention is to use a nitrogen-methanol mixture to generate the atmosphere of the furnace, and to vary the relative proportions of nitrogen and methanol.
  • the proportion of methanol in the mixture is increased, this increase possibly going as far as the introduction of pure methanol during or during this brief period.
  • the flow rate of the mixture and the proportions thereof can be varied simultaneously, so as to keep the nitrogen flow rate substantially constant.
  • This variant is that shown in FIG. 4 with a flow rate D ' H from to to to + ⁇ t', etc ... of a mixture peddling 20% nitrogen and 80% methanol and a flow rate D ' L , lower to D ' H of a mixture containing 40% nitrogen and 60% methanol.
  • This example represents the prior art typically used to date.
  • cementing of steel transmission parts of grade 16NC6 is carried out, for which the cementation depth sought at 550 HV1 is from 0.7 to 0.9 mm.
  • the oven temperature is 920 ° C, the charges, introduced every 7 minutes, being 150 kg.
  • the carbon potential that we are trying to maintain in the carburizing zone is 0.8%.
  • the duration of the opening of the loading door, at the entrance of the oven, is 27 seconds.
  • the atmosphere injected into the oven is obtained using a nitrogen-methanol mixture, in the ratio 40/60 (atrmsphere called "endothermic").
  • the flow rate of the injected atmosphere is 19 m3 / hour.
  • the consumption of atmosphere per cycle (of 7 minutes) is therefore 2.22m 3 .
  • Example 7 In the same oven, all other things being equal, the same parts are treated to obtain the same final conditions as in Example 1.
  • the atmosphere injected into the furnace in the preceding example is replaced by an atmosphere of variable composition, for variable durations, represented in FIG. 7.
  • the atmosphere Atm 2 is injected with a nitrogen / methanol ratio equal to 20/80 at a flow rate of 24 m 3 / h. Then the atmosphere Atm 1 is injected at a flow rate of 12 m 3 / h, for 3 minutes and 50 seconds.
  • the gas consumption during a cycle is 1.57 m 3 .
  • the variations in carbon potential are shown in Figure 8 to scale. (Note that on the time scale ( Figures 6, 7 and 8), F represents the instant of closing of the oven door).
  • the depth cemented at 550 HV1 of the parts in the batch is between 0.7 and 0.9 mm.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
  • Tunnel Furnaces (AREA)
  • Superconductors And Manufacturing Methods Therefor (AREA)
  • Multiple-Way Valves (AREA)
  • Inorganic Compounds Of Heavy Metals (AREA)
  • Carbon And Carbon Compounds (AREA)
EP86401584A 1985-08-14 1986-07-16 Beschleunigtes Karburierungsverfahren in einem kontinuierlichen Ofen Expired EP0213991B1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT86401584T ATE40416T1 (de) 1985-08-14 1986-07-16 Beschleunigtes karburierungsverfahren in einem kontinuierlichen ofen.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8512380A FR2586259B1 (fr) 1985-08-14 1985-08-14 Procede de cementation rapide dans un four continu
FR8512380 1985-08-14

Publications (2)

Publication Number Publication Date
EP0213991A1 true EP0213991A1 (de) 1987-03-11
EP0213991B1 EP0213991B1 (de) 1989-01-25

Family

ID=9322228

Family Applications (1)

Application Number Title Priority Date Filing Date
EP86401584A Expired EP0213991B1 (de) 1985-08-14 1986-07-16 Beschleunigtes Karburierungsverfahren in einem kontinuierlichen Ofen

Country Status (11)

Country Link
US (1) US4769090A (de)
EP (1) EP0213991B1 (de)
JP (1) JPS6240359A (de)
AT (1) ATE40416T1 (de)
AU (1) AU587045B2 (de)
BR (1) BR8603865A (de)
CA (1) CA1259550A (de)
DE (1) DE3661943D1 (de)
ES (1) ES8706850A1 (de)
FR (1) FR2586259B1 (de)
ZA (1) ZA865392B (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2626292A1 (fr) * 1988-01-26 1989-07-28 Paturle Aciers Procede de traitement thermochimique superficiel de bandes d'acier et en particulier de bandes de faibles epaisseurs et installation pour sa mise en oeuvre
FR2639250A1 (de) * 1988-11-24 1990-05-25 Air Liquide
EP0465226A1 (de) * 1990-07-03 1992-01-08 Dowa Mining Co., Ltd. Verfahren und Anlage zur Gasaufkohlung

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2586258B1 (fr) * 1985-08-14 1987-10-30 Air Liquide Procede pour la cementation rapide et homogene d'une charge dans un four
FR2623209B1 (fr) * 1987-11-17 1993-09-03 Air Liquide Procede de traitement thermique sous atmosphere gazeuse a base d'azote et d'hydrocarbure
IT1229078B (it) * 1988-03-16 1991-07-18 Air Liquide Procedimento e dispositivo di trattamento di ricottura di articoli metallici.
DE4400391A1 (de) * 1994-01-08 1995-07-13 Messer Griesheim Gmbh Verfahren zur Vermeidung von Randoxidation beim Aufkohlen von Stählen
US5934871A (en) * 1997-07-24 1999-08-10 Murphy; Donald G. Method and apparatus for supplying a anti-oxidizing gas to and simultaneously cooling a shaft and a fan in a heat treatment chamber
CN102828143A (zh) * 2012-08-30 2012-12-19 天津创真金属科技有限公司 工件高温渗碳工艺
CN113215519B (zh) * 2021-04-19 2023-08-15 常州天山重工机械有限公司 一种无马弗罐碳饱和控制工艺

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2439241A1 (fr) * 1978-10-19 1980-05-16 Trw Inc Procede de reglage, a l'aide du debit d'introduction d'un vehicule gazeux inerte, du traitement thermique tel que la carbonitruration, la cementation ou le recuit d'objets ferreux
EP0049531A1 (de) * 1980-10-08 1982-04-14 Linde Aktiengesellschaft Verfahren zum Einsatzhärten metallischer Werkstücke
EP0049532A1 (de) * 1980-10-08 1982-04-14 Linde Aktiengesellschaft Verfahren zum Aufkohlen und kohlungsneutralen Glühen von Werkstücken
GB2092183A (en) * 1981-01-14 1982-08-11 Holcroft & Co Method of controlling furnace atmospheres
DE3310733A1 (de) * 1983-03-24 1984-10-04 Daimler-Benz Ag, 7000 Stuttgart Verfahren zur verringerung des schutzgasverbrauchs sowie der randoxidation von zu behandelnden bauteilen in schleusen-durchstossanlagen mit brennbarem schutzgas

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US26935A (en) * 1860-01-24 Attaching bonnets to sails
FR439241A (fr) * 1911-01-25 1912-06-08 Giovanni Romei Perfectionnements dans les roues pour chars et autres véhicules en général
US2955062A (en) * 1952-02-27 1960-10-04 Midland Ross Corp Method for carburizing in a continuous furnace
US4049472A (en) * 1975-12-22 1977-09-20 Air Products And Chemicals, Inc. Atmosphere compositions and methods of using same for surface treating ferrous metals
US4145232A (en) * 1977-06-03 1979-03-20 Union Carbide Corporation Process for carburizing steel
CH632013A5 (de) * 1977-09-22 1982-09-15 Ipsen Ind Int Gmbh Verfahren zur gasaufkohlung von werkstuecken aus stahl.
US4306918A (en) * 1980-04-22 1981-12-22 Air Products And Chemicals, Inc. Process for carburizing ferrous metals
FR2527641A1 (fr) * 1982-05-28 1983-12-02 Air Liquide Procede de traitement thermique de pieces metalliques par carburation
JPS6130659A (ja) * 1984-07-20 1986-02-12 Tokyo Netsu Shiyori Kogyo Kk 窒素ベ−スガス浸炭法
FR2586258B1 (fr) * 1985-08-14 1987-10-30 Air Liquide Procede pour la cementation rapide et homogene d'une charge dans un four

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2439241A1 (fr) * 1978-10-19 1980-05-16 Trw Inc Procede de reglage, a l'aide du debit d'introduction d'un vehicule gazeux inerte, du traitement thermique tel que la carbonitruration, la cementation ou le recuit d'objets ferreux
EP0049531A1 (de) * 1980-10-08 1982-04-14 Linde Aktiengesellschaft Verfahren zum Einsatzhärten metallischer Werkstücke
EP0049532A1 (de) * 1980-10-08 1982-04-14 Linde Aktiengesellschaft Verfahren zum Aufkohlen und kohlungsneutralen Glühen von Werkstücken
GB2092183A (en) * 1981-01-14 1982-08-11 Holcroft & Co Method of controlling furnace atmospheres
DE3310733A1 (de) * 1983-03-24 1984-10-04 Daimler-Benz Ag, 7000 Stuttgart Verfahren zur verringerung des schutzgasverbrauchs sowie der randoxidation von zu behandelnden bauteilen in schleusen-durchstossanlagen mit brennbarem schutzgas

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
CHEMICAL ABSTRACTS, vol. 87, no. 6, 1977, page 218, résumé no. 42820u, Columbus, Ohio, US; & JP-A-76 24 983 (NIPPON KINZOKU CO. LTD.) 28-07-1976 *

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2626292A1 (fr) * 1988-01-26 1989-07-28 Paturle Aciers Procede de traitement thermochimique superficiel de bandes d'acier et en particulier de bandes de faibles epaisseurs et installation pour sa mise en oeuvre
FR2639250A1 (de) * 1988-11-24 1990-05-25 Air Liquide
EP0375477A1 (de) * 1988-11-24 1990-06-27 L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude Verfahren zur Herstellung einer Atmosphäre zur thermischen Behandlung durch Lufttrennung durch Permeation
EP0465226A1 (de) * 1990-07-03 1992-01-08 Dowa Mining Co., Ltd. Verfahren und Anlage zur Gasaufkohlung
EP0825274A2 (de) * 1990-07-03 1998-02-25 Dowa Mining Co., Ltd. Verfahren zur Gasaufkohlung
EP0825274A3 (de) * 1990-07-03 1998-05-13 Dowa Mining Co., Ltd. Verfahren zur Gasaufkohlung

Also Published As

Publication number Publication date
ATE40416T1 (de) 1989-02-15
FR2586259B1 (fr) 1987-10-30
ZA865392B (en) 1987-03-25
CA1259550A (fr) 1989-09-19
ES556249A0 (es) 1987-07-01
FR2586259A1 (fr) 1987-02-20
AU587045B2 (en) 1989-08-03
BR8603865A (pt) 1987-03-24
EP0213991B1 (de) 1989-01-25
JPS6240359A (ja) 1987-02-21
ES8706850A1 (es) 1987-07-01
US4769090A (en) 1988-09-06
JPS6356304B2 (de) 1988-11-08
AU6022586A (en) 1987-02-19
DE3661943D1 (en) 1989-03-02

Similar Documents

Publication Publication Date Title
EP0213991B1 (de) Beschleunigtes Karburierungsverfahren in einem kontinuierlichen Ofen
EP1885904B1 (de) Niederdruckcarbonitrierverfahren und -vorrichtung
CA1208528A (fr) Procede de traitement thermique de pieces metalliques par carburation
CH634112A5 (fr) Procede de carburation de l'acier.
CA1215901A (fr) Procede de durcissement superficiel de pieces metalliques
EP0408511B1 (de) Verfahren und Vorrichtung zur thermischen oder thermochemischen Behandlung von Stahl
CA1140438A (en) Process for carburizing ferrous metals
EP0532386B1 (de) Verfahren und Vorrichtung zum Aufkohlen von Stahl in einer Atmosphere von niedrigem Druck
CA1253397A (fr) Procede d'incineration de dechets a temperature controlee
EP0317407A1 (de) Verfahren zur Wärmebehandlung in einer Gasatmosphäre auf der Basis von Stickstoff und Kohlenwasserstoff
CA1259551A (fr) Procede de traitement thermique pour la realisation de pieces en acier resistant a la corrosion
EP1280943B1 (de) Verfahren zur niederdruck-aufkohlung
EP0213011B1 (de) Verfahren zur schnellen und homogenen Aufkohlung von Werkstücken in einem Ofen
FR2500848A1 (fr) Procede pour reguler la composition de l'atmosphere d'un four de traitement thermique de metaux
WO1999055921A1 (fr) Procede de cementation ou carbonitruration de pieces metalliques
US5827375A (en) Process for carburizing ferrous metal parts
EP0985054B1 (de) Verfahren zum kontinuierlichen herstellen von stahlband mit verbesserten oberflächeneigenschaften zum tiefziehen
FR2712898A1 (fr) Procédé de cémentation gazeuse.
FR2656003A1 (fr) Procede et installation de traitement thermique ou thermochimique d'un acier, permettant le controle de l'enrichissement en carbone de la zone superficielle.
EP1409761A1 (de) Verfahren zum zementieren oder karbonitrieren von stählen mit kohlenmonoxid
CH329743A (fr) Procédé d'élaboration d'objets métalliques non poreux

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 19860719

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE CH DE FR GB IT LI LU NL SE

17Q First examination report despatched

Effective date: 19880519

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): AT BE CH DE FR GB IT LI LU NL SE

ITF It: translation for a ep patent filed
REF Corresponds to:

Ref document number: 40416

Country of ref document: AT

Date of ref document: 19890215

Kind code of ref document: T

GBT Gb: translation of ep patent filed (gb section 77(6)(a)/1977)
REF Corresponds to:

Ref document number: 3661943

Country of ref document: DE

Date of ref document: 19890302

PLBI Opposition filed

Free format text: ORIGINAL CODE: 0009260

PLBI Opposition filed

Free format text: ORIGINAL CODE: 0009260

26 Opposition filed

Opponent name: DEGUSSA AG, FRANKFURT - ZWEIGNIEDERLASSUNG WOLFGAN

Effective date: 19891023

26 Opposition filed

Opponent name: LINDE AKTIENGESELLSCHAFT, WIESBADEN

Effective date: 19891025

Opponent name: DEGUSSA AG, FRANKFURT - ZWEIGNIEDERLASSUNG WOLFGAN

Effective date: 19891023

NLR1 Nl: opposition has been filed with the epo

Opponent name: LINDE AKTIENGESELLSCHAFT

Opponent name: DEGUSSA AG

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 19910610

Year of fee payment: 6

Ref country code: AT

Payment date: 19910610

Year of fee payment: 6

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 19910612

Year of fee payment: 6

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: SE

Payment date: 19910614

Year of fee payment: 6

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: CH

Payment date: 19910619

Year of fee payment: 6

PLBN Opposition rejected

Free format text: ORIGINAL CODE: 0009273

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: OPPOSITION REJECTED

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: BE

Payment date: 19910624

Year of fee payment: 6

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: LU

Payment date: 19910628

Year of fee payment: 6

Ref country code: DE

Payment date: 19910628

Year of fee payment: 6

ITTA It: last paid annual fee
PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: NL

Payment date: 19910731

Year of fee payment: 6

27O Opposition rejected

Effective date: 19910311

NLR2 Nl: decision of opposition
EPTA Lu: last paid annual fee
PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LU

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19920716

Ref country code: GB

Effective date: 19920716

Ref country code: AT

Effective date: 19920716

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SE

Effective date: 19920717

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LI

Effective date: 19920731

Ref country code: CH

Effective date: 19920731

Ref country code: BE

Effective date: 19920731

BERE Be: lapsed

Owner name: L' AIR LIQUIDE S.A. POUR L'ETUDE ET L'EXPLOITATION

Effective date: 19920731

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: NL

Effective date: 19930201

NLV4 Nl: lapsed or anulled due to non-payment of the annual fee
GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 19920716

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Effective date: 19930331

REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Effective date: 19930401

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

EUG Se: european patent has lapsed

Ref document number: 86401584.7

Effective date: 19930204

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES;WARNING: LAPSES OF ITALIAN PATENTS WITH EFFECTIVE DATE BEFORE 2007 MAY HAVE OCCURRED AT ANY TIME BEFORE 2007. THE CORRECT EFFECTIVE DATE MAY BE DIFFERENT FROM THE ONE RECORDED.

Effective date: 20050716