EP0054962A1 - Non polluting process for carburizing steel in a molten salt bath - Google Patents
Non polluting process for carburizing steel in a molten salt bath Download PDFInfo
- Publication number
- EP0054962A1 EP0054962A1 EP81110690A EP81110690A EP0054962A1 EP 0054962 A1 EP0054962 A1 EP 0054962A1 EP 81110690 A EP81110690 A EP 81110690A EP 81110690 A EP81110690 A EP 81110690A EP 0054962 A1 EP0054962 A1 EP 0054962A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- salt
- carburizing
- bath
- alkaline earth
- steel
- 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.)
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- 150000003839 salts Chemical class 0.000 title claims abstract description 43
- 238000000034 method Methods 0.000 title claims abstract description 37
- 238000005255 carburizing Methods 0.000 title claims abstract description 28
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 21
- 239000010959 steel Substances 0.000 title claims abstract description 21
- 238000010791 quenching Methods 0.000 claims abstract description 8
- 239000003513 alkali Substances 0.000 claims abstract description 7
- 150000004820 halides Chemical class 0.000 claims abstract description 7
- 239000000203 mixture Substances 0.000 claims abstract description 6
- 230000000171 quenching effect Effects 0.000 claims abstract description 6
- 239000000463 material Substances 0.000 claims abstract description 3
- XFXPMWWXUTWYJX-UHFFFAOYSA-N Cyanide Chemical compound N#[C-] XFXPMWWXUTWYJX-UHFFFAOYSA-N 0.000 claims description 13
- 229910001615 alkaline earth metal halide Inorganic materials 0.000 claims description 9
- 238000002360 preparation method Methods 0.000 claims description 5
- 229910052783 alkali metal Inorganic materials 0.000 claims description 2
- -1 alkali metal cyanate Chemical class 0.000 claims description 2
- GKKCIDNWFBPDBW-UHFFFAOYSA-M potassium cyanate Chemical compound [K]OC#N GKKCIDNWFBPDBW-UHFFFAOYSA-M 0.000 claims description 2
- 239000000276 potassium ferrocyanide Substances 0.000 claims description 2
- 230000001105 regulatory effect Effects 0.000 claims description 2
- XOGGUFAVLNCTRS-UHFFFAOYSA-N tetrapotassium;iron(2+);hexacyanide Chemical compound [K+].[K+].[K+].[K+].[Fe+2].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-] XOGGUFAVLNCTRS-UHFFFAOYSA-N 0.000 claims description 2
- FGUUSXIOTUKUDN-IBGZPJMESA-N C1(=CC=CC=C1)N1C2=C(NC([C@H](C1)NC=1OC(=NN=1)C1=CC=CC=C1)=O)C=CC=C2 Chemical compound C1(=CC=CC=C1)N1C2=C(NC([C@H](C1)NC=1OC(=NN=1)C1=CC=CC=C1)=O)C=CC=C2 FGUUSXIOTUKUDN-IBGZPJMESA-N 0.000 claims 1
- ZVCDLGYNFYZZOK-UHFFFAOYSA-M sodium cyanate Chemical compound [Na]OC#N ZVCDLGYNFYZZOK-UHFFFAOYSA-M 0.000 claims 1
- GTSHREYGKSITGK-UHFFFAOYSA-N sodium ferrocyanide Chemical compound [Na+].[Na+].[Na+].[Na+].[Fe+2].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-].N#[C-] GTSHREYGKSITGK-UHFFFAOYSA-N 0.000 claims 1
- 239000000264 sodium ferrocyanide Substances 0.000 claims 1
- 235000012247 sodium ferrocyanide Nutrition 0.000 claims 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims 1
- XLJMAIOERFSOGZ-UHFFFAOYSA-M cyanate Chemical compound [O-]C#N XLJMAIOERFSOGZ-UHFFFAOYSA-M 0.000 abstract 1
- 229910052799 carbon Inorganic materials 0.000 description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 3
- WCUXLLCKKVVCTQ-UHFFFAOYSA-M Potassium chloride Chemical compound [Cl-].[K+] WCUXLLCKKVVCTQ-UHFFFAOYSA-M 0.000 description 2
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- WDIHJSXYQDMJHN-UHFFFAOYSA-L barium chloride Chemical compound [Cl-].[Cl-].[Ba+2] WDIHJSXYQDMJHN-UHFFFAOYSA-L 0.000 description 2
- 229910001626 barium chloride Inorganic materials 0.000 description 2
- 239000002360 explosive Substances 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- YBVAXJOZZAJCLA-UHFFFAOYSA-N nitric acid nitrous acid Chemical compound ON=O.O[N+]([O-])=O YBVAXJOZZAJCLA-UHFFFAOYSA-N 0.000 description 2
- FGIUAXJPYTZDNR-UHFFFAOYSA-N potassium nitrate Chemical compound [K+].[O-][N+]([O-])=O FGIUAXJPYTZDNR-UHFFFAOYSA-N 0.000 description 2
- LPXPTNMVRIOKMN-UHFFFAOYSA-M sodium nitrite Chemical compound [Na+].[O-]N=O LPXPTNMVRIOKMN-UHFFFAOYSA-M 0.000 description 2
- 229910001203 Alloy 20 Inorganic materials 0.000 description 1
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- LJYRLGOJYKPILZ-UHFFFAOYSA-N murexide Chemical compound [NH4+].N1C(=O)NC(=O)C(N=C2C(NC(=O)NC2=O)=O)=C1[O-] LJYRLGOJYKPILZ-UHFFFAOYSA-N 0.000 description 1
- 239000003345 natural gas Substances 0.000 description 1
- LGQLOGILCSXPEA-UHFFFAOYSA-L nickel sulfate Chemical compound [Ni+2].[O-]S([O-])(=O)=O LGQLOGILCSXPEA-UHFFFAOYSA-L 0.000 description 1
- 229910000363 nickel(II) sulfate Inorganic materials 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000001103 potassium chloride Substances 0.000 description 1
- 235000011164 potassium chloride Nutrition 0.000 description 1
- 235000010333 potassium nitrate Nutrition 0.000 description 1
- 239000004323 potassium nitrate Substances 0.000 description 1
- 239000011833 salt mixture Substances 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 238000007086 side reaction Methods 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- 235000010288 sodium nitrite Nutrition 0.000 description 1
- 238000004448 titration Methods 0.000 description 1
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
- C23C8/40—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 liquids, e.g. salt baths, liquid suspensions
- C23C8/52—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 liquids, e.g. salt baths, liquid suspensions more than one element being applied in one step
- C23C8/54—Carbo-nitriding
- C23C8/56—Carbo-nitriding of ferrous surfaces
-
- 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
- C23C8/40—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 liquids, e.g. salt baths, liquid suspensions
- C23C8/42—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 liquids, e.g. salt baths, liquid suspensions only one element being applied
- C23C8/44—Carburising
- C23C8/46—Carburising of ferrous surfaces
Definitions
- the present invention relates to a method for carburizing steel in a salt bath, whereby a high cyanide content in the bath is progressively avoided.
- Carburization processes for steel in a salt bath are available in various versions in the prior art, however the processes in the prior art generally have the disadvantage of having a high cyanide content in the salt bath.
- This high cyanide content in the baths is questionable for environmental reasons.
- a steel crucible with a capacity of 80 l is filled with 50 kg of preparation salt, which consists of 60% barium chloride, 20% sodium chloride and 20% potassium chloride.
- This filling is brought to a temperature of 800 ° C by means of a heating system operated with natural gas, whereby a completely homogeneous melt is created.
- the steel crucible filling is then heated to 900 ° C and then the workpieces, namely gearwheels (consisting of case hardening steel from alloy 20 MnCr 5) with a unit weight of 1 kg, are suspended from a steel wire in the aforementioned melt and carburized within 4 hours.
- gearwheels consisting of case hardening steel from alloy 20 MnCr 5
- the case hardening depth is 0.83 mm.
- FIG. 1 shows the C content of the workpiece as a function of the edge distance; the C content is given in% by weight; the carburizing depth of the C is measured in mm.
- Figure 2 shows the hardness curve of the workpiece depending on the edge distance.
- the hardness is given in hardness HV1 and the edge distance in mm.
- the cyanide content is checked by sampling and titration with nickel sulfate and murexide as an indicator.
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Heat Treatment Of Articles (AREA)
- Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
- Solid-Phase Diffusion Into Metallic Material Surfaces (AREA)
- Treatment Of Steel In Its Molten State (AREA)
Abstract
Description
Die vorliegende Erfindung betrifft ein Verfahren zum Aufkohlen von Stahl im Salzbad, wobei fortschrittlicherweise ein hoher Cyanidgehalt im Bad vermieden wird.The present invention relates to a method for carburizing steel in a salt bath, whereby a high cyanide content in the bath is progressively avoided.
Aufkohlungsverfahren von Stahl im Salzbad stehen dem Stand der Technik in verschiedenen Varianten zur Verfügung, jedoch sind die Verfahren des Standes der Technik generell mit dem Nachteil behaftet, im Salzbad einen hohen Cyanidgehalt aufzuweisen. Dieser hohe Cyanidgehalt der Bäder ist aus Umweltschutzgründen bedenklich. Es ist ferner bei solchen Bädern mit hohem Cyanidgehalt nur bedingt möglich, die aus den Bädern kommenden Werkstücke direkt in einem Abschrecksalzbad abzuschrecken, da der hohe Cyanidgehalt sehr heftige explosionsartige Reaktionen zwischen flüssigem Nitrit-Nitrat einerseits und dem Cyanid andererseits auslösen kann.Carburization processes for steel in a salt bath are available in various versions in the prior art, however the processes in the prior art generally have the disadvantage of having a high cyanide content in the salt bath. This high cyanide content in the baths is questionable for environmental reasons. In such baths with a high cyanide content, it is also only possible to quench the workpieces coming from the baths directly in a quenching salt bath, since the high cyanide content can trigger very violent explosive reactions between liquid nitrite nitrate on the one hand and the cyanide on the other hand.
Alle diese Nachteile des Standes der Technik werden bei dem erfindungsgemäßen Verfahren zum Aufkohlen der eingangs genannten Gattung unter Erreichung von Vorteilen überwunden; insbesondere wird mit dem erfindungsgemäßen Verfahren eine umweltfreundliche Aufkohlungsmöglichkeit von Stahl im Salzbad geschaffen. Ein weiterer großer Vorteil des erfindungsgemäßen Verfahrens besteht darin, daß sämtliche verwendete Salzmischungen alkali-cyanidfrei sind.All of these disadvantages of the prior art are overcome in the process according to the invention for carburizing the type mentioned at the outset, with advantages being achieved; in particular, the method according to the invention creates an environmentally friendly possibility of carburizing steel in a salt bath. Another great advantage of the process according to the invention is that all of the salt mixtures used are alkali-cyanide-free.
Ferner ist es nach dem erfindungsgemäßen Verfahren möglich, die aus dem Bad kommenden Werkstücke unmittelbar anschließend in nitritnitrathaltigen Salzbädern abzuschrecken ohne daß unerwünschte Nebenreaktionen wie beispielsweise explosionsartige Oxidationsreaktionen stattfinden. Das erfindungsgemäße Verfahren zum Aufkohlen von Stahl im Salzbad ist durch die folgenden Verfahrensschritte gekennzeichnet:
- a) der Verfahrensbehälter wird mit einem Ansatzsalz gefüllt, das aus einem Gemisch aus Alkalihalogenid und Erdalkalihalogenid besteht;
- b) das Ansatzsalz wird zum Schmelzen gebracht;
- c) es wird Zugabesalz hinzugegeben, das aus einem Gemisch von Erdalkalihalogenid, Alkaliferrocyanid und Alkalicyanat besteht, wobei das Erdalkalihalogenid des Zugabesalzes chemisch mit dem Erdalkalihalogenid des Ansatzsalzes übereinstimmt;
- d) die Verfahrensbehälterfüllung wird auf die Anwendungstemperatur erhitzt;
- e) das zu behandelnde Werkstück wird in .die Verfahrensbehälterfüllung, nämlich in das Aufkohlungsbad getaucht und dort bis zur Erreichung der gewünschten Aufkohlungstiefe belassen;
- f) das Werkstück wird aus dem Aufkohlungsbad entnommen und je nach Werkstoffart im entsprechenden Abschreck-Medium abgeschreckt.
- a) the process container is filled with a preparation salt, which consists of a mixture of alkali halide and alkaline earth metal halide;
- b) the starting salt is melted;
- c) addition salt is added, which consists of a mixture of alkaline earth metal halide, alkali ferrocyanide and alkali metal cyanate, the alkaline earth metal halide of the addition salt chemically corresponding to the alkaline earth metal halide of the preparation salt;
- d) the process container filling is heated to the application temperature;
- e) the workpiece to be treated is immersed in the process tank filling, namely in the carburizing bath and left there until the desired carburizing depth is reached;
- f) the workpiece is removed from the carburizing bath and, depending on the type of material, quenched in the appropriate quenching medium.
Das Wesen vorliegender Erfindung wird nun anhand eines Ausführungsbeispiels weiterhin erläutert:The essence of the present invention will now be further explained using an exemplary embodiment:
Ein Stahltiegel eines Fassungsvermögens von 80 1 wird mit 50 kg Ansatzsalz gefüllt, das zu 60 % aus Bariumchlorid, zu 20 % aus Natriumchlorid und zu 20 % aus Kaliumchlorid besteht.A steel crucible with a capacity of 80 l is filled with 50 kg of preparation salt, which consists of 60% barium chloride, 20% sodium chloride and 20% potassium chloride.
Diese Füllung wird mittels einer mit Erdgas betriebenen Heizung auf eine Temperatur von 800°C gebracht, wobei eine völlig homogene Schmelze entsteht.This filling is brought to a temperature of 800 ° C by means of a heating system operated with natural gas, whereby a completely homogeneous melt is created.
Sodann werden 10 kg Zugabesalz hinzugefügt, das zu 60 % aus Bariumchlorid, zu 20 % aus Kaliumferrocyanid ( = gelbes Blutlaugensalz ) und zu 20 % aus Kaliumcyanat besteht.Then 10 kg of addition salt are added, which consists of 60% barium chloride, 20% potassium ferrocyanide (= yellow blood-lye salt) and 20% potassium cyanate.
Die Stahltiegelfüllung wird nun auf 900°C aufgeheizt und sodann die Werkstücke, nämlich Zahnräder (bestehend aus Einsatzstahl aus Legierung 20 MnCr 5) mit einem Stückgewicht von 1 kg, an einem Stahldraht hängend in die vorgenannte Schmelze eingebracht und innerhalb von 4 Stunden aufgekohlt.The steel crucible filling is then heated to 900 ° C and then the workpieces, namely gearwheels (consisting of case hardening steel from alloy 20 MnCr 5) with a unit weight of 1 kg, are suspended from a steel wire in the aforementioned melt and carburized within 4 hours.
Sodann entnimmt man diese Werkstücke aus der Schmelze und gibt sie unmittelbar danach in ein Warmbad ein, das zu 50 % aus Kaliumnitrat und zu 50 % aus Natriumnitrit besteht; die Abschrecktemperatur beträgt 200°C.Then these workpieces are removed from the melt and immediately put into a warm bath which consists of 50% potassium nitrate and 50% sodium nitrite; the quenching temperature is 200 ° C.
Es wurde ein Rand-Kohlenstoffgehalt von 0,955 % C erreicht.An edge carbon content of 0.955% C was reached.
Die Einsatzhärtungstiefe beträgt 0,83 mm.The case hardening depth is 0.83 mm.
Der Kohlenstoffverlauf und der Härteverlauf dieser Werkstücke (Zahnräder) sind in der beiliegenden Figur 1 und der beiliegenden Figur 2 angegeben.The carbon profile and the hardness profile of these workpieces (gear wheels) are given in the attached FIG. 1 and the attached FIG. 2.
Die Figur 1 zeigt den C-Gehalt des Werkstückes in Abhängigkeit vom Randabstand; der C-Gehalt ist in Gew.-% angegeben; die Aufkohlungstiefe des C ist in mm gemessen.FIG. 1 shows the C content of the workpiece as a function of the edge distance; the C content is given in% by weight; the carburizing depth of the C is measured in mm.
Figur 2 zeigt den Härteverlauf des Werkstückes in Abhängigkeit vom Randabstand.Figure 2 shows the hardness curve of the workpiece depending on the edge distance.
Die Härte ist in Härte HV1 und der Randabstand in mm angegeben.The hardness is given in hardness HV1 and the edge distance in mm.
Im kontinuierlichen Betrieb erfolgt die Kontrolle des Cyanidgehaltes durch Probenahmen und Titration mit Nickelsulfat und Murexid als Indikator.In continuous operation, the cyanide content is checked by sampling and titration with nickel sulfate and murexide as an indicator.
Alle 3 Stunden wurde 0,5 kg Zugabesalz zugegeben, wobei sich ein Cyanidgehalt von etwa 1,5 % einstellt.0.5 kg of addition salt was added every 3 hours, resulting in a cyanide content of about 1.5%.
Innerhalb einer Zeitdauer von 3 Monaten wurden 30 Probebolzen der Stahlqualität 20 MnCr 5, ferner 30 Probebolzen aus der Legierung C 15 und schließlich 18 Probebolzen aus der Legierung 18 Cr Ni 8 getestet und zwar jeweils 4 Stunden bei Temperaturen von 900°C.Within a period of 3 months, 30 steel M 20 Cr 5 test bolts, 30 C 15 alloy bolts and finally 18 18
Dabei ergaben sich Rand-Kohlenstoffwerte zwischen 0,9 und 0,98 Gew.-% C.This resulted in marginal carbon values between 0.9 and 0.98% by weight of C.
Damit ist die ständige Reproduzierbarkeit des erfindungsgemäßen Verfahrens sichergestellt.This ensures the constant reproducibility of the method according to the invention.
Aufgrund des ständigen Badgebrauches ist auch eine ständige Kontrolle des geringen Cyanidgehalts möglich. Die Regulierung des Cyanidgehalts d.h. die Sicherstellung des gleichbleibenden geringen Cyanidgehaltes wird fortschrittlicherweise nicht etwa durch Zugabe an Cyanid erreicht. bzw. geregelt, sondern lediglich durch Einbringen des Zugabesalzes gemäß den Angaben im Merkmal c) des Hauptpatentanspruchs 1.Due to the constant use of the bath, a constant control of the low cyanide content is possible. The regulation of the cyanide content i.e. progressively, ensuring the constant low cyanide content is not achieved by adding cyanide, for example. or regulated, but only by introducing the addition salt according to the information in feature c) of the main patent claim 1.
Gegebenenfalls kann man ferner beispielsweise nach Entstehen der kompletten Schmelze, also nach Beendigung der Verfahrensstufe c) des Hauptpatentanspruchs 1 zur Erreichung einer sogenannten künstlichen Alterung des Bades geringe Mengen an Soda, beispielsweise 1 Gew.-% bezogen auf die Badmenge hinzugeben.If necessary, it is also possible to add small amounts of soda, for example 1% by weight, based on the amount of bath, for example after the complete melt has formed, that is to say after process step c) of main patent claim 1 has ended, in order to achieve what is known as artificial aging of the bath.
Alle %-Angaben der vorliegenden Offenbarung sind Gew.-%.All percentages of the present disclosure are percentages by weight.
Claims (9)
daß in der Verfahrensstufe a) bei normaler Temperatur der Verfahrensbehälter zu 80 % der gewünschten Gesamtfüllmenge mit Ansatzsalz gefüllt wird.2. Process for carburizing steel in a salt bath, characterized in that
that in process step a) the process container is filled to 80% of the desired total filling quantity with starting salt at normal temperature.
dadurch gekennzeichnet,
daß man in der Verfahrensstufe b) das Ansatzsalz auf eine Temperatur von ca. 800°C erhitzt, wobei Schmelzfluß eintritt.3. A method for carburizing steel in a salt bath according to claim 1,
characterized,
that the process salt is heated to a temperature of about 800 ° C. in process step b), melt flow occurring.
dadurch gekennzeichnet,
daß in der Verfahrensstufe c) 20 % Zugabesalz hinzugegeben wird , das aus Erdalkalihalogenid, Kaliumferrocyanid oder Natriumferrocyanid sowie aus Kaliumcyanat oder Natriumcyanat besteht.4. A method for carburizing steel in a salt bath according to claim 1,
characterized,
that in process step c) 20% addition salt is added, which consists of alkaline earth metal halide, potassium ferrocyanide or sodium ferrocyanide and potassium cyanate or sodium cyanate.
dadurch gekennzeichnet,
daß man das Bad auf eine Anwendungstemperatur von etwa 880°C bis 1020°C erhitzt.5. A method for carburizing steel in a salt bath according to claim 1,
characterized,
that the bath is heated to an application temperature of about 880 ° C to 1020 ° C.
dadurch gekennzeichnet,
daß man das zu behandelnde Werkstück wie beispielsweise eine aus Stahl bestehende Kurbelwelle oder ein Zahnrad in das Aufkohlungsbad eintaucht und dort je nach der gewünschten Aufkohlungstiefe beläBt.6. A method for carburizing steel in a salt bath according to claim 1,
characterized,
that the workpiece to be treated, such as a steel crankshaft or a gearwheel, is immersed in the carburizing bath and left there depending on the desired carburizing depth.
daß die Aufkohlungstemperatur kontrolliert und/oder geregelt wird.7. A method for carburizing steel in a salt bath according to at least one of claims 1 to 6, characterized in that
that the carburizing temperature is checked and / or regulated.
dadurch gekennzeichnet,
daß man in der Verfahrensstufe f) das aus dem Bad entnommene Werkstück in Wasser, Öl oder im Abschrecksalzbad abschreckt.8. A method for carburizing steel in a salt bath according to claim 1,
characterized,
that in process step f) the workpiece removed from the bath is quenched in water, oil or in the quenching salt bath.
daß die Regelung des geringen Cyanidgehalts des Bades durch Einbringen des Zugabesalzes durchgeführt wird.9. A method for carburizing steel in a salt bath according to at least one of claims 1 to 8, characterized in that
that the control of the low cyanide content of the bath is carried out by introducing the addition salt.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AT81110690T ATE12951T1 (en) | 1980-12-23 | 1981-12-22 | ECO-FRIENDLY SALT BATH CARBURIZING PROCESS FOR STEEL. |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE3048607 | 1980-12-23 | ||
| DE3048607A DE3048607C2 (en) | 1980-12-23 | 1980-12-23 | Cyanide-free process for carburizing steel and adding salt to carry out the process |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0054962A1 true EP0054962A1 (en) | 1982-06-30 |
| EP0054962B1 EP0054962B1 (en) | 1985-04-24 |
Family
ID=6120037
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP81110690A Expired EP0054962B1 (en) | 1980-12-23 | 1981-12-22 | Non polluting process for carburizing steel in a molten salt bath |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0054962B1 (en) |
| AT (1) | ATE12951T1 (en) |
| CH (1) | CH647002A5 (en) |
| DE (2) | DE3048607C2 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6461448B1 (en) | 1998-08-12 | 2002-10-08 | Swagelok Company | Low temperature case hardening processes |
| US6547888B1 (en) | 2000-01-28 | 2003-04-15 | Swagelok Company | Modified low temperature case hardening processes |
| DE102006026883B3 (en) * | 2006-06-09 | 2007-08-16 | Durferrit Gmbh | Hardening of stainless steel comprises submerging in hot bath of molten salts |
| EP2055801A1 (en) * | 2007-10-31 | 2009-05-06 | Durferrit GmbH | Method for hardening stainless steel surfaces on workpieces and fused salt for performing the method |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6165597A (en) * | 1998-08-12 | 2000-12-26 | Swagelok Company | Selective case hardening processes at low temperature |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1053243A (en) * | 1900-01-01 |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1952090A (en) * | 1931-07-11 | 1934-03-27 | American Cyanamid Co | Case-hardening metals |
-
1980
- 1980-12-23 DE DE3048607A patent/DE3048607C2/en not_active Expired
-
1981
- 1981-08-12 CH CH519481A patent/CH647002A5/en not_active IP Right Cessation
- 1981-12-22 EP EP81110690A patent/EP0054962B1/en not_active Expired
- 1981-12-22 AT AT81110690T patent/ATE12951T1/en not_active IP Right Cessation
- 1981-12-22 DE DE8181110690T patent/DE3170212D1/en not_active Expired
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1053243A (en) * | 1900-01-01 |
Non-Patent Citations (1)
| Title |
|---|
| CHEMICAL ABSTRACTS, Band. 70, 1969, Zusammenfassung Nr. 22221v, seite 179 Columbus, Ohio, (US) & Metalloved. Term. Obrab. Metal 1968, (10), 8-11 Funshtein, YA.N.: "Effect of the Bath Composition on the Depth and wear Resistance of a Cyanided Layer.", * das ganze dokument * * |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6461448B1 (en) | 1998-08-12 | 2002-10-08 | Swagelok Company | Low temperature case hardening processes |
| US6547888B1 (en) | 2000-01-28 | 2003-04-15 | Swagelok Company | Modified low temperature case hardening processes |
| DE102006026883B3 (en) * | 2006-06-09 | 2007-08-16 | Durferrit Gmbh | Hardening of stainless steel comprises submerging in hot bath of molten salts |
| DE102006026883B8 (en) * | 2006-06-09 | 2007-10-04 | Durferrit Gmbh | Process for hardening stainless steel and molten salt for carrying out the process |
| US7909943B2 (en) | 2006-06-09 | 2011-03-22 | Durferrit Gmbh | Method for hardening stainless steel and molten salt bath for realizing said process |
| EP2055801A1 (en) * | 2007-10-31 | 2009-05-06 | Durferrit GmbH | Method for hardening stainless steel surfaces on workpieces and fused salt for performing the method |
| US8083866B2 (en) | 2007-10-31 | 2011-12-27 | Durferrit Gmbh | Method for hardening the surfaces of work pieces made of stainless steel, and a molten salt bath for realizing the method |
Also Published As
| Publication number | Publication date |
|---|---|
| CH647002A5 (en) | 1984-12-28 |
| EP0054962B1 (en) | 1985-04-24 |
| DE3170212D1 (en) | 1985-05-30 |
| DE3048607A1 (en) | 1982-07-01 |
| DE3048607C2 (en) | 1983-07-07 |
| ATE12951T1 (en) | 1985-05-15 |
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