EP0375491A1 - Verfahren und Anlage für Wärmebehandlungen wie Einsatzhärten, Karbonitrieren oder Erwärmung vor dem Härten von metallischen Werkstoffen - Google Patents

Verfahren und Anlage für Wärmebehandlungen wie Einsatzhärten, Karbonitrieren oder Erwärmung vor dem Härten von metallischen Werkstoffen Download PDF

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Publication number
EP0375491A1
EP0375491A1 EP89403347A EP89403347A EP0375491A1 EP 0375491 A1 EP0375491 A1 EP 0375491A1 EP 89403347 A EP89403347 A EP 89403347A EP 89403347 A EP89403347 A EP 89403347A EP 0375491 A1 EP0375491 A1 EP 0375491A1
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EP
European Patent Office
Prior art keywords
nitrogen
oxygen content
generator
carbonitriding
treatment
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
EP89403347A
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English (en)
French (fr)
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EP0375491B1 (de
Inventor
Alain Combier
Patrice Ollivier
Jean-Marc Viant
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
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Application filed by Air Liquide SA, LAir Liquide SA pour lEtude et lExploitation des Procedes Georges Claude filed Critical Air Liquide SA
Priority to AT89403347T priority Critical patent/ATE104361T1/de
Publication of EP0375491A1 publication Critical patent/EP0375491A1/de
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Publication of EP0375491B1 publication Critical patent/EP0375491B1/de
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    • 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
    • C23C8/28—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 more than one element being applied in one step
    • C23C8/30—Carbo-nitriding
    • 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
    • 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
    • C21D1/76—Adjusting the composition of the atmosphere

Definitions

  • the present invention relates to thermal treatments for carburizing, carbonitriding and heating before quenching steels intended to ensure surface hardening of metal parts.
  • Nitrogen can come from: . from a cryogenic plant generally located far from the user, and in this case it is delivered in gaseous form (compressed bottles) or liquid form (liquid storage and vaporization before use). . a non cryogenic generator placed directly at the customer, which is either an adsorption generator known under the name of "PSA", or a gas permeation generator, or with “membranes” for example, which leads to an advantageous economy compared to cryogenic nitrogen, but also to problems related to a relative impurity of the gas produced, in particular because the oxygen content is relatively high, generally from 0.1 to 5%.
  • PSA adsorption generator
  • gas permeation generator or with “membranes” for example
  • the raw nitrogen produced is therefore impure, because it contains a little oxygen and traces of water.
  • the generator extraction factor flow of nitrogen produced / flow of treated air
  • its production capacity which is obviously to the detriment of the cost price of the gas treated.
  • a “PSA” type generator usually has the following performances as a function of the oxygen content in the gas produced.
  • the residual oxygen is transformed into CO, H2O and CO2.
  • the additional hydrocarbon makes it possible in particular to maintain a low H2O and CO2 content, despite the presence of oxygen in the nitrogen, provided that the oxygen content is not too high. If this is not the case, an additional hydrocarbon content qualified as excessive must be injected, since it can cause soot formation, heterogeneous carburizing, drops in the CO content. Ultimately, obtaining a high potential carbon in the atmosphere may be impossible, which is obviously contrary to good treatment.
  • the maximum oxygen content compatible with the majority of the treatment cycles provided for in case hardening, in carbonitriding and in heating before quenching of steels is of the order of 2% in nitrogen.
  • the residual H enO and CO2 contents may be contained at low values, generally less than 0.6% for H2O and 0.3% for CO2.
  • the atmosphere formed inside the furnace diffuses into the refractory bricks and at the bricks / atmosphere interface, a balance is reached when the furnace is in continuous operation, but a significant problem remains during the periods of non-operation of the oven. It is indeed more and more common that the heat treatment workshop undergoes interruptions of operation of relatively long durations, for example during the weekend rest. In this case, the treatment atmosphere is of course no longer injected into the furnace not only for reasons of economy and also of safety since this atmosphere is potentially explosive (high hydrogen and CO content) and toxic ( high CO level). On the other hand, the oven temperature is often also somewhat lowered.
  • the nitrogen used comes from a cryogenic source, the residual oxygen content in the oven and in the refractory bricks remains very low, and the restart of the oven in production, the so-called reconditioning period, is then very short, generally 15 minutes to a few hours depending in particular on the oven temperature.
  • the reconditioning of the furnace can take considerably more time, thus penalizing the productivity of the installation.
  • the purge is conventionally done from the treatment atmosphere injected again into the oven. This contains in particular a high hydrogen content.
  • This gas which is made up of a very "small” molecule diffuses very quickly, so that the hydrogen transforms the oxygen contained in the refractory bricks into water vapor, so that the water vapor content thus produced reaches 4%.
  • This 4% water vapor content is incompatible with the subsequent treatment which requires values of less than 0.6%. It is therefore necessary to chemically destroy or purge this water vapor. Purging water vapor is always a difficult operation because this polar molecule has the property of being very easily adsorbed on the surface of solids.
  • refractory bricks by their porosity, have a very large specific surface.
  • the invention relates to a process for heat treatment of carburizing or carbonitriding or heating before quenching of steel parts, of the type where an auxiliary gas mixture based on nitrogen, methanol, the where appropriate ammonia, to constitute a treatment atmosphere in an oven of the single wall type of refractory bricks, according to which crude nitrogen is used as the nitrogen component resulting from the separation of the air produced by an adsorption generator or permeation, the degree of nitrogen purity of which, or the residual oxygen content, is determined by its extraction rate and which is adjusted so as to generate in operation a nitrogen gas having a residual oxygen content of the order 2%, and where a resumption of treatment after an interruption phase of significant duration is preceded by an injection of nitrogen into the oven, and this process is characterized in that the purge nitrogen is supplied to a flow rate much lower than the treatment flow rate coming from the treatment nitrogen generator itself, adjusted for this purpose to a lower extraction rate, such that the residual oxygen content does not exceed 0.3% and preferably is between 0.
  • the method according to the invention has the double merit of requiring no other source of gas for purging and of ensuring this purging under economic conditions that are the least detrimental to the operating efficiency of the cementation, carbonitriding, or heating before quenching.
  • the invention also relates to an installation for heat treatment of carburizing, carbonitriding or heating before quenching of metal parts, of the type comprising: a non-muffled treatment oven, that is to say with a single wall of refractory bricks, different sources of constituents in the fluid state of developing an atmosphere for carburizing heat treatment, carbonitriding, or heating before quenching, among which, for the nitrogen constituent, a generator for separating nitrogen from the air by adsorption or permeation selective and this installation is characterized by means for adjusting the nitrogen extraction rate on at least two levels, namely a high level with residual oxygen content of the order of 2% and a low level with residual content in oxygen less than 0.3% and preferably between 0.1% and 0.2%.
  • a liquid nitrogen storage 10 provided with its vaporization device 11 and a pressure reducer 12, opens onto the supply line directly upstream of the flow meter 4 and serves to ensure the clipping of the extreme peaks and the rescue in generator shutdown.
  • the buffer tanks 6 and 9 are used to absorb variations in the flow rate called by the user, in normal operation or in reduced operation respectively. They are not necessary if the called flow is stable. Note that the three-way valves 3, 5 and 7 can be - either operated manually by the user according to his needs - either operated automatically by an appropriate device (timer, customer load detection, ).
  • a single buffer tank may be sufficient, but then it should be possible to purge it for approximately the time necessary for the generator to change from normal nitrogen quality to purge nitrogen quality.
  • the excess of compressed air compared to the normal step is either vented, with no energy saving effect, or the compressor vacuum device switches on at regular intervals, resulting in significant energy savings.
  • the following values can be expected: O2 content in nitrogen 2% 0.1% nominal flow rate of a "PSA" type generator (m3 / h) 100 25 nominal power of generator type "PSA” (kW) Pn 90% Pn

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Metallurgy (AREA)
  • Mechanical Engineering (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
  • Heat Treatments In General, Especially Conveying And Cooling (AREA)
  • Furnace Details (AREA)
  • Heat Treatment Of Strip Materials And Filament Materials (AREA)
  • Resistance Heating (AREA)
  • Meat, Egg Or Seafood Products (AREA)
  • Muffle Furnaces And Rotary Kilns (AREA)
EP89403347A 1988-12-20 1989-12-04 Verfahren und Anlage für Wärmebehandlungen wie Einsatzhärten, Karbonitrieren oder Erwärmung vor dem Härten von metallischen Werkstoffen Expired - Lifetime EP0375491B1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT89403347T ATE104361T1 (de) 1988-12-20 1989-12-04 Verfahren und anlage fuer waermebehandlungen wie einsatzhaerten, karbonitrieren oder erwaermung vor dem haerten von metallischen werkstoffen.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8816792A FR2640646B1 (fr) 1988-12-20 1988-12-20 Procede et installation de traitement thermique de cementation, carbonitruration ou chauffage avant trempe de pieces metalliques
FR8816792 1988-12-20

Publications (2)

Publication Number Publication Date
EP0375491A1 true EP0375491A1 (de) 1990-06-27
EP0375491B1 EP0375491B1 (de) 1994-04-13

Family

ID=9373150

Family Applications (1)

Application Number Title Priority Date Filing Date
EP89403347A Expired - Lifetime EP0375491B1 (de) 1988-12-20 1989-12-04 Verfahren und Anlage für Wärmebehandlungen wie Einsatzhärten, Karbonitrieren oder Erwärmung vor dem Härten von metallischen Werkstoffen

Country Status (11)

Country Link
US (1) US5045126A (de)
EP (1) EP0375491B1 (de)
JP (1) JPH02217459A (de)
AT (1) ATE104361T1 (de)
AU (1) AU625618B2 (de)
CA (1) CA2005823C (de)
DE (1) DE68914624T2 (de)
ES (1) ES2050834T3 (de)
FR (1) FR2640646B1 (de)
PT (1) PT92615B (de)
ZA (1) ZA899627B (de)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110257761A (zh) * 2019-06-14 2019-09-20 武汉汇九厨具科技有限公司 一种无涂层耐磨防锈不粘铁锅及其制造工艺

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5298090A (en) * 1992-12-22 1994-03-29 Air Products And Chemicals, Inc. Atmospheres for heat treating non-ferrous metals and alloys
US5348592A (en) * 1993-02-01 1994-09-20 Air Products And Chemicals, Inc. Method of producing nitrogen-hydrogen atmospheres for metals processing
DE4400391A1 (de) * 1994-01-08 1995-07-13 Messer Griesheim Gmbh Verfahren zur Vermeidung von Randoxidation beim Aufkohlen von Stählen
NZ314334A (en) * 1996-04-19 1997-09-22 Boc Group Inc Method of heat treating a metal with nitrogen rich gas preheated and then having oxygen-reactive gas added
CN104060265A (zh) * 2014-06-18 2014-09-24 滁州市艾德模具设备有限公司 热作模具耐高温处理工艺
CN112501544A (zh) * 2020-08-27 2021-03-16 苏州新豪轴承股份有限公司 轴承零件加工工艺

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2450878A1 (fr) * 1979-03-05 1980-10-03 Air Liquide Installation generatrice d'une atmosphere de traitement thermique des metaux
US4805881A (en) * 1987-05-28 1989-02-21 Gas Research Institute Internal gas generator for heat treating furnace

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
IRON AND STEEL ENGINEER, vol. 39, no. 8, août 1962, pages 124-134; R. HERBERT et al.: "Nitrogen from an air-separation plant as a heat-treating atmosphere" *
JOURNAL OF HEAT TREATING, vol. 5, no. 2, 1988, pages 97-114, Springer-Verlag, New York Inc., New York, US; J. SLYCKE et al.: "Assessment of nitrogen based atmospheres for industrial heat treating" *
METAL PROGRESS, vol. 127, no. 6, mai 1985, page 67, Metals Park, Ohio, US; "New products: New air separation technology makes nitrogen for heat treating" *
STEEL IN THE U.S.S.R., vol. 15, no. 12, décembre 1985, pages 610-611, Londres, GB; V.M. REBIKOV: "Single-component controlled atmosphere in muffle-less shaft type electric furnaces" *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110257761A (zh) * 2019-06-14 2019-09-20 武汉汇九厨具科技有限公司 一种无涂层耐磨防锈不粘铁锅及其制造工艺

Also Published As

Publication number Publication date
US5045126A (en) 1991-09-03
ZA899627B (en) 1990-09-26
ES2050834T3 (es) 1994-06-01
JPH02217459A (ja) 1990-08-30
EP0375491B1 (de) 1994-04-13
ATE104361T1 (de) 1994-04-15
CA2005823C (fr) 1994-12-13
FR2640646B1 (fr) 1993-02-05
DE68914624T2 (de) 1994-07-21
PT92615B (pt) 1995-09-12
DE68914624D1 (de) 1994-05-19
CA2005823A1 (fr) 1990-06-20
FR2640646A1 (fr) 1990-06-22
AU4713389A (en) 1990-06-28
AU625618B2 (en) 1992-07-16
PT92615A (pt) 1990-06-29

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