EP0103717A1 - Inert salt bath for heating steel - Google Patents
Inert salt bath for heating steel Download PDFInfo
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- EP0103717A1 EP0103717A1 EP83107597A EP83107597A EP0103717A1 EP 0103717 A1 EP0103717 A1 EP 0103717A1 EP 83107597 A EP83107597 A EP 83107597A EP 83107597 A EP83107597 A EP 83107597A EP 0103717 A1 EP0103717 A1 EP 0103717A1
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- European Patent Office
- Prior art keywords
- salt bath
- regenerator
- bath
- inert
- inert salt
- Prior art date
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- 150000003839 salts Chemical class 0.000 title claims abstract description 21
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 12
- 239000010959 steel Substances 0.000 title claims abstract description 12
- 238000010438 heat treatment Methods 0.000 title claims abstract description 10
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 8
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 7
- 239000000203 mixture Substances 0.000 claims abstract description 6
- 239000011833 salt mixture Substances 0.000 claims abstract description 5
- 241000219112 Cucumis Species 0.000 claims description 10
- 235000015510 Cucumis melo subsp melo Nutrition 0.000 claims description 10
- FJJCIZWZNKZHII-UHFFFAOYSA-N [4,6-bis(cyanoamino)-1,3,5-triazin-2-yl]cyanamide Chemical compound N#CNC1=NC(NC#N)=NC(NC#N)=N1 FJJCIZWZNKZHII-UHFFFAOYSA-N 0.000 claims description 10
- 239000003513 alkali Substances 0.000 claims description 5
- QJGQUHMNIGDVPM-UHFFFAOYSA-N nitrogen group Chemical group [N] QJGQUHMNIGDVPM-UHFFFAOYSA-N 0.000 claims description 3
- 150000002894 organic compounds Chemical class 0.000 claims description 3
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 claims description 2
- 229910001514 alkali metal chloride Inorganic materials 0.000 claims description 2
- 229910001617 alkaline earth metal chloride Inorganic materials 0.000 claims description 2
- 239000004202 carbamide Substances 0.000 claims description 2
- 150000003857 carboxamides Chemical class 0.000 claims description 2
- LELOWRISYMNNSU-UHFFFAOYSA-N hydrogen cyanide Chemical class N#C LELOWRISYMNNSU-UHFFFAOYSA-N 0.000 claims description 2
- 150000003918 triazines Chemical class 0.000 claims description 2
- 210000003608 fece Anatomy 0.000 claims 1
- 229920000642 polymer Polymers 0.000 claims 1
- 150000003841 chloride salts Chemical class 0.000 abstract 1
- -1 nitrogen-containing organic compound Chemical class 0.000 abstract 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 6
- ORUIBWPALBXDOA-UHFFFAOYSA-L magnesium fluoride Chemical compound [F-].[F-].[Mg+2] ORUIBWPALBXDOA-UHFFFAOYSA-L 0.000 description 6
- 229910052710 silicon Inorganic materials 0.000 description 6
- 238000005261 decarburization Methods 0.000 description 5
- 229910001635 magnesium fluoride Inorganic materials 0.000 description 5
- 238000002844 melting Methods 0.000 description 5
- 230000008018 melting Effects 0.000 description 5
- 239000010703 silicon Substances 0.000 description 5
- 239000000126 substance Substances 0.000 description 5
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical group [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 4
- WDIHJSXYQDMJHN-UHFFFAOYSA-L barium chloride Chemical compound [Cl-].[Cl-].[Ba+2] WDIHJSXYQDMJHN-UHFFFAOYSA-L 0.000 description 4
- 150000001805 chlorine compounds Chemical class 0.000 description 4
- 230000007797 corrosion Effects 0.000 description 4
- 238000005260 corrosion Methods 0.000 description 4
- 239000000155 melt Substances 0.000 description 4
- 230000008929 regeneration Effects 0.000 description 4
- 238000011069 regeneration method Methods 0.000 description 4
- 230000004580 weight loss Effects 0.000 description 4
- 238000005255 carburizing Methods 0.000 description 3
- 238000006116 polymerization reaction Methods 0.000 description 3
- 239000010802 sludge Substances 0.000 description 3
- 229910000997 High-speed steel Inorganic materials 0.000 description 2
- 229920000877 Melamine resin Polymers 0.000 description 2
- 229910052784 alkaline earth metal Inorganic materials 0.000 description 2
- 229910001626 barium chloride Inorganic materials 0.000 description 2
- 229910052796 boron Inorganic materials 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- NEHMKBQYUWJMIP-UHFFFAOYSA-N chloromethane Chemical compound ClC NEHMKBQYUWJMIP-UHFFFAOYSA-N 0.000 description 2
- 230000006378 damage Effects 0.000 description 2
- JKWMSGQKBLHBQQ-UHFFFAOYSA-N diboron trioxide Chemical compound O=BOB=O JKWMSGQKBLHBQQ-UHFFFAOYSA-N 0.000 description 2
- JDSHMPZPIAZGSV-UHFFFAOYSA-N melamine Chemical compound NC1=NC(N)=NC(N)=N1 JDSHMPZPIAZGSV-UHFFFAOYSA-N 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 2
- 229910010271 silicon carbide Inorganic materials 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 1
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 150000001340 alkali metals Chemical class 0.000 description 1
- 150000001342 alkaline earth metals Chemical class 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 229910052788 barium Inorganic materials 0.000 description 1
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- NEHMKBQYUWJMIP-NJFSPNSNSA-N chloro(114C)methane Chemical compound [14CH3]Cl NEHMKBQYUWJMIP-NJFSPNSNSA-N 0.000 description 1
- 239000003245 coal Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000007859 condensation product Substances 0.000 description 1
- 239000003599 detergent Chemical group 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000011888 foil Substances 0.000 description 1
- WSFSSNUMVMOOMR-UHFFFAOYSA-N formaldehyde Substances O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- ZFSLODLOARCGLH-UHFFFAOYSA-N isocyanuric acid Chemical compound OC1=NC(O)=NC(O)=N1 ZFSLODLOARCGLH-UHFFFAOYSA-N 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229940050176 methyl chloride Drugs 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- 239000011591 potassium Substances 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
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
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/34—Methods of heating
- C21D1/44—Methods of heating in heat-treatment baths
- C21D1/46—Salt baths
Definitions
- the invention relates to an inert salt bath for heating steels to austenitizing temperatures, consisting of a mixture of essentially alkali and alkaline earth chlorides and a regenerator.
- the parts To harden steel parts such as tools, the parts must be heated to the austenitizing temperature. In many cases, this heating takes place in salt baths. However, the heating in the salt bath must be such that the surface of the components to be hardened does not undergo any chemical changes.
- the salt baths used should therefore, for example, neither exert an oxygen effect, which could result in decarburization, nor should carburization take place which, at the appropriate hardening temperatures, can possibly lead to melting and thus destruction of the workpieces. Nor should they have a corrosive effect.
- Melting salts for heating steel parts to austenitizing temperatures generally contain chlorides of alkali and alkaline earth metals, mostly chlorides of sodium, potassium and barium.
- the composition depends on the particular application, in particular on the working temperature, ie the melting point of the salt mixture. Melting of this kind, which comes from very pure substances are generally met the requirements placed on the surface quality, they are inert.
- the production of such glow baths from very pure substances is very expensive, so that lower-quality starting materials have to be used and the baths are thus no longer inert.
- even originally inert glow baths lose their inert character due to the introduction of impurities, in particular the inevitable introduction of iron oxide, detergent residues, processing oils, etc. This not only leads to decarburization of the workpieces, but also to an increased corrosion attack on the components and the electrodes of the furnaces containing the molten salts and thus at higher costs.
- regenerators or regeneration processes are used. It is known that molten salt for high-temperature baths, for example for hardening high-speed steel, can be added with methyl chloride, thereby avoiding decarburization. However, the success of this treatment is often insufficient and in any case only temporary, since methyl chloride must not be introduced into the melt during the treatment of workpieces.
- regenerators are, for example, silicon or silicon carbide.
- silicon generally serves the desired purpose, ie prevents decarburization, the silicon is occasionally sintered onto the workpiece surface, which may result in irreparable damage. It also forms generally a tough sludge in the molten salt that is difficult to remove.
- Silicon carbide has practically the same disadvantages as silicon itself, but above all it cannot be used if carburizing of the workpiece surface must be avoided under all circumstances.
- This object has been achieved according to the invention in that 0.01 to 2% by weight of a carbon and nitrogen-containing polymeric organic compound is added to the salt mixture as regenerator. These compounds can be added to the bath during operation or during the preparation of the salt mixture or salts.
- Polymeric triazine compounds, polymeric hydrocyanic acids, polymeric carboxamides and / or polymeric urea have proven particularly useful as regenerators.
- the degree of polymerization must be chosen so that the reaction in the bath is not too stormy. In some cases degrees of polymerization n> 3 are already sufficient, but they are preferably much higher.
- Suitable regenerators are triaminotriazine-formaldehyde condensation products and in particular melon, a polymerization product of melamine, which can be prepared by heating melamine to temperatures of 500.degree.
- melon a polymerization product of melamine
- other nitrogen-containing polymeric organic compounds such as cyanuric acid or azulmic acid, have also proven successful.
- the baths can be operated at temperatures from 700 to 1300 ° C,
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- Engineering & Computer Science (AREA)
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- Crystallography & Structural Chemistry (AREA)
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- Metallurgy (AREA)
- Organic Chemistry (AREA)
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- Anti-Oxidant Or Stabilizer Compositions (AREA)
- Compositions Of Macromolecular Compounds (AREA)
- Curing Cements, Concrete, And Artificial Stone (AREA)
- Devices For Medical Bathing And Washing (AREA)
- Heat Treatment Of Steel (AREA)
- Cosmetics (AREA)
- Nitrogen Condensed Heterocyclic Rings (AREA)
- Heat Treatment Of Articles (AREA)
- Electroplating And Plating Baths Therefor (AREA)
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Abstract
Description
Die Erfindung betrifft ein inertes Salzbad zum Erwärmen von Stählen auf Austenitisierungstemperaturen, bestehend aus einem Gemisch von im wesentlichen Alkali- und Erdalkalichloriden und einem Regenerator.The invention relates to an inert salt bath for heating steels to austenitizing temperatures, consisting of a mixture of essentially alkali and alkaline earth chlorides and a regenerator.
Zum Härten von Stahlteilen, wie beispielsweise Werkzeugen, müssen die Teile auf die Austenitisierungstemperatur erwärmt werden. Diese Erwärmung erfolgt in vielen Fällen in Salzbädern. Dabei muß die Erwärmung im Salzbad aber so erfolgen, daß die Oberfläche der zu härtenden Bauteile keinerlei chemische Veränderungen erfährt. Die verwendeten Salzbäder sollen also zum Beispiel weder eine Sauerstoffeinwirkung ausüben, wodurch Entkohlung eintreten könnte, noch sollte eine Aufkohlung stattfinden, die bei entsprechenden Härtetemperaturen eventuell zu Aufschmelzungen und damit zur Zerstörung der Werkstücke führen kann. Auch sollen sie nicht korrodierend wirken.To harden steel parts such as tools, the parts must be heated to the austenitizing temperature. In many cases, this heating takes place in salt baths. However, the heating in the salt bath must be such that the surface of the components to be hardened does not undergo any chemical changes. The salt baths used should therefore, for example, neither exert an oxygen effect, which could result in decarburization, nor should carburization take place which, at the appropriate hardening temperatures, can possibly lead to melting and thus destruction of the workpieces. Nor should they have a corrosive effect.
Salzschmelzen zum Erwärmen von Stahlteilen auf Austeniti-sierungstemperaturcenthalten im allgemeinen Chloride der Alkali- und Erdalkalimetalle, meist Chloride von Natrium, Kalium und Barium. Die Zusammensetzung richtet sich nach dem besonderen Anwendungsfall, insbesondere nach der Arbeitstemperatur, d.h. dem Schmelzpunkt des Salzgemisches. Schmelzen dieser Art, die aus sehr reinen Substanzen hergestellt werden, erfüllen im allgemeinen die gestellten Anforderungen an die Dberflächenqualität, sie sind inert. Die Herstellung derartiger Glühbäder aus sehr reinen Substanzen ist jedoch sehr teuer, so daß man geringerwertige Ausgangsstoffe verwenden muß und damit die Inertheit der Bäder verliert. Dazu kommt, daß selbst ursprünglich inerte Glühbäder durch das Hereinschleppen von Verunreinigungen, insbesondere durch das unvermeidliche Hereinschleppen von Eisenoxid, Waschmittelreste, Bearbeitungsöle usw..ihren inerten Charakter verlieren. Dadurch kommt es nicht nur zur Entkohlung der Werkstücke, sondern auch zu einem vermehrten Korrosionsangriff auf die Bauteile und die Elektroden der die Salzschmelzen enthaltenden Öfen und damit zu höheren Kosten.Melting salts for heating steel parts to austenitizing temperatures generally contain chlorides of alkali and alkaline earth metals, mostly chlorides of sodium, potassium and barium. The composition depends on the particular application, in particular on the working temperature, ie the melting point of the salt mixture. Melting of this kind, which comes from very pure substances are generally met the requirements placed on the surface quality, they are inert. However, the production of such glow baths from very pure substances is very expensive, so that lower-quality starting materials have to be used and the baths are thus no longer inert. In addition, even originally inert glow baths lose their inert character due to the introduction of impurities, in particular the inevitable introduction of iron oxide, detergent residues, processing oils, etc. This not only leads to decarburization of the workpieces, but also to an increased corrosion attack on the components and the electrodes of the furnaces containing the molten salts and thus at higher costs.
Um dennoch die gewünschte Inertheit der Salzschmelzen zu erreichen, arbeitet man mit sogenannten Regeneratoren oder Regenerierungsverfahren. Es ist bekannt, daß man Salzschmelzen für Hochtemperaturbäder, beispielsweise zum Härten von Schnellarbeitsstahl, Methylchlorid zusetzen kann, wodurch eine Abkohlung vermieden wird. Der Erfolg dieser Behandlung ist jedoch oft nicht ausreichend und auf jeden Fall nur vorübergehend, da während der Behandlung von Werkstücken eine Methylchlorideinleitung in die Schmelze nicht erfolgen darf.In order to nevertheless achieve the desired inertness of the salt melts, so-called regenerators or regeneration processes are used. It is known that molten salt for high-temperature baths, for example for hardening high-speed steel, can be added with methyl chloride, thereby avoiding decarburization. However, the success of this treatment is often insufficient and in any case only temporary, since methyl chloride must not be introduced into the melt during the treatment of workpieces.
Andere Stoffe, die als Regeneratoren verwendet werden, sind z.B. Silizium oder Siliziumcarbid. Das Silizium erfüllt zwar im allgemeinen den gewünschten Zweck, d.h. verhindert die Abkohlung, jedoch kommt es gelegentlich zum Aufsintern des Siliziums auf die Werkstückoberfläche, womit unter Umständen irreparable Schäden entstehen. Außerdem bildet es im allgemeinen einen schwer entfernbaren zähen Schlamm in der Salzschmelze.Other substances that are used as regenerators are, for example, silicon or silicon carbide. Although the silicon generally serves the desired purpose, ie prevents decarburization, the silicon is occasionally sintered onto the workpiece surface, which may result in irreparable damage. It also forms generally a tough sludge in the molten salt that is difficult to remove.
Siliziumcarbid hat praktisch die gleichen Nachteile wie das Silizium selbst, kann aber vor allen Dingen dann nicht verwendet werden, wenn eine Aufkohlung der Werkstückoberfläche unter allen Umständen vermieden werden muß.Silicon carbide has practically the same disadvantages as silicon itself, but above all it cannot be used if carburizing of the workpiece surface must be avoided under all circumstances.
Ähnlich arbeiten Regenerierungsverfahren, bei denen Kohle oder Graphit verwendet wird, z.B. in Form von Stäben, die in die Schmelze getaucht werden. Auch hier ist nicht zu vermeiden, daß Kohlepartikelchen im Bad verbleiben und damit eine aufkohlende Wirkung hervorrufen.Regeneration processes using coal or graphite, e.g. in the form of rods that are immersed in the melt. Here, too, it cannot be avoided that carbon particles remain in the bath and thus have a carburizing effect.
Besonders wirksame Regenerierungssubstanzen sind für die sogenannten Hochtemperaturbäder gefunden worden. Dort verwendet man Magnesiumfluorid in Mischung mit Bortrioxid als Regenerator. Solche Bäder sind absolut inert. Diescsetzt jedoch voraus, daß verhältnismäßig große Mengen von Magnesiumfluorid (z.B. 6%) verwendet werden. Dieser hohe Zusatz führt jedoch zu einem verhältnismäßig hohen Schlammanfall aus Magnesium- und Eisenoxid, was in solchen Fällen stört, wo die Elektrodenbeheizung der Salzbäder vom Boden her erfolgt. In solchen Fällen ist die Verwendung dieser Regeneratoren nicht möglich. Außerdem sind sie nur bei Temperaturen über 1.100 C verwendbar.Particularly effective regeneration substances have been found for the so-called high-temperature baths. There, magnesium fluoride mixed with boron trioxide is used as a regenerator. Such baths are absolutely inert. However, this requires that relatively large amounts of magnesium fluoride (e.g. 6%) are used. However, this high addition leads to a relatively high amount of sludge from magnesium and iron oxide, which is disturbing in those cases where the electrode heating of the salt baths takes place from the bottom. In such cases, the use of these regenerators is not possible. In addition, they can only be used at temperatures above 1,100 C.
Es war daher Aufgabe der vorliegenden Erfindung, ein inertes Salzbad zum Erwärmen von Stählen auf Austenitisierungstemperatur zu finden, bestehend aus einem Gemisch von im wesentlichen Alkali- und Erdalkalichloriden und einem Regenerator, daß auch bei relativ tiefen Temperaturen wirkt, keine Korrosion und keine Aufschmelzungen auf den Oberflächen der behandelten Teile hervorruft und keine Schlammbildung in der Salzschmelze verursacht.It was therefore an object of the present invention to find an inert salt bath for heating steels to the austenitizing temperature, consisting of a mixture of essentially alkali metal and alkaline earth metal chlorides and a regenerator, that works even at relatively low temperatures, does not cause corrosion and no melting on the surfaces of the treated parts and does not cause sludge formation in the salt melt.
Diese Aufgabe wurde erfindungsgemäß dadurch gelöst, daß dem Salzgemisch als Regenerator 0,01 bis 2 Gew.% einer Kohlenstoff und Stickstoff enthaltenden polymeren organischen Verbindung zugesetzt wird. Diese Verbindungen können dem Bad während des Betriebs oder bereits bei der Herstellung des Salzgemisches bzw. der Salze zugesetzt werden.This object has been achieved according to the invention in that 0.01 to 2% by weight of a carbon and nitrogen-containing polymeric organic compound is added to the salt mixture as regenerator. These compounds can be added to the bath during operation or during the preparation of the salt mixture or salts.
Besonders bewährt als Regeneratoren haben sich polymere Triazinverbindungen, polymere Cyanwasserstoffsäuren, polymere Carbonsäureamide und/oder polymerer Harnstoff. Der Polymerisationsgrad muß dabei so gewählt werden, daß die Reaktion im Bad nicht zu stürmisch abläuft. Zum Teil sind Polymerisationsgrade n>3 bereits ausreichend, vorzugsweise liegen sie jedoch wesentlich höher.Polymeric triazine compounds, polymeric hydrocyanic acids, polymeric carboxamides and / or polymeric urea have proven particularly useful as regenerators. The degree of polymerization must be chosen so that the reaction in the bath is not too stormy. In some cases degrees of polymerization n> 3 are already sufficient, but they are preferably much higher.
Geeignete Regeneratoren sind Triaminotriazin-Formaldehyd-Kondensationsprodukte und insbesondere Melon, ein Polymerisationsprodukt des Melamins, herstellbar durch Erwärmen von Melamin auf Temperaturen von 500°C. Bewährt haben sich jedoch auch andere stickstoffhaltige polymere organische Verbindungen, wie Cyanursäure oder Azulminsäure. Die Bäder können bei Temperaturen von 700 bis 1300°C betrieben werden,Suitable regenerators are triaminotriazine-formaldehyde condensation products and in particular melon, a polymerization product of melamine, which can be prepared by heating melamine to temperatures of 500.degree. However, other nitrogen-containing polymeric organic compounds, such as cyanuric acid or azulmic acid, have also proven successful. The baths can be operated at temperatures from 700 to 1300 ° C,
Folgende Beispiele sollen das erfindungsgemäße Salzbad näher erläutern:
- 1. Ein Glühsalzbad mit 70 % Bariumchlorid und 30 % Alkalichlorid wird bei Temperaturen von 1050°C eingesetzt, um Werkzeuge aus Warmarbeitsstahl zu härten. Trotz Regenerierung mit Silizium zeigt eine Stahlfolie mit einem Xohlenstoffgehalt von 1 %, die 20 Minuten bei dieser Temperatur in das Bad gehängt und dann abgeschreckt wurde, einen starken Gewichtsverlust von ca. 180 mg/dm2. Stahlwerkzeuge, die in diesem Bad behandelt wurden, zeigten insbesondere an den feinbearbeiteten Oberflächen kräftige Anfressungen, die die Weiterverarbeitung des Werkzeuges unmöglich machten. Die Werkzeuge sind Ausschuß.
- 1. A salt bath with 70% barium chloride and 30% alkali Chloride is used at temperatures of 1050 ° C to harden tools made of hot-work steel. Despite regeneration with silicon, a steel foil with a carbon content of 1%, which was hung in the bath for 20 minutes at this temperature and then quenched, shows a strong weight loss of approx. 180 mg / dm 2 . Steel tools that were treated in this bath showed strong corrosion, particularly on the finely machined surfaces, which made further processing of the tool impossible. The tools are rejects.
Dem gleichen Bad wurden dann 0,05 % Melon zugesetzt. Nach Beendigung der nach der Zugabe einsetzenden Reaktion zeigte eine Folie, die wie oben beschrieben behandelt wird, nur noch einen Gewichtsverlust von ca. 20 mg/dm2. Stahlwerkzeuge, die darin behandelt wurden, hatten einwandfreie Oberflächen.
- 2. Bei einem weiteren Versuch, unter Bedingungen wie unter Beispiel 1 geschildert, wird das Glühbad von vornherein mit einer Mischung angesetzt, die außer Alkali- und Erdalkalichloriden ca. 1 % Melon enthält. Die in diesem Bad behandelten Werkzeuge aus Warmarbeitsstahl waren frei von Oberflächenkorrosion.
- 3. Ein magnesiumfluoridhaltiges Bad wird wie folgt angesetzt:
- ca. 98,0 % Bariumchlorid
- ca. 1,0 % Magnesiumfluorid
- ca. 0,2 % B 2 0 3 0,5 % Melon
- 2. In a further experiment, under conditions as described in Example 1, the glow bath is prepared from the outset with a mixture which, in addition to alkali and alkaline earth chlorides, contains about 1% melon. The tools made of hot-work steel treated in this bath were free from surface corrosion.
- 3. A bath containing magnesium fluoride is prepared as follows:
- approx. 98.0% barium chloride
- approx. 1.0% magnesium fluoride
- c a. 0.2% B 2 0 3 0.5% melon
In einem solchen Bad behandelte Werkzeuge aus Schnellarbeitsstahl weisen keine Abkohlung auf. Eine 20 Minuten bei 1220oC behandelte Folie mit einem Ausgangskohlenstoffgehalt von 1,0 % hat nach Abschluß dieser Behandlung immer noch einen Kohlenstoffgehalt von über 0,9 %, was beweist, daß das Bad praktisch nicht abkohlt. Der Gewichtsverlust einer Folie liegt bei 80 mg/dm2, ohne Zusatz von Melon führen derartige Schmelzen zu Gewichtsverlusten von über 200 mg/dm2.Tools made from high-speed steel treated in such a bath have no decarburization. A film treated at 1220 ° C. for 20 minutes with a starting carbon content of 1.0% still has a carbon content of over 0.9% after the completion of this treatment, which proves that the bath practically does not carbonize. The weight loss of a film is 80 mg / dm 2 ; without the addition of melon, such melts lead to weight losses of over 200 mg / dm 2 .
Der Versuch wird nach 50 Laufstunden des Bades wiederholt. Bei den geringen Magnesiumfluoridgehalten hätte das Bad ohne Melonzusatz stark abkohlende Wirkung gezeigt. Mit Melonzusatz verhält sich das Bad jedoch genauso inert wie bei der InbetriebnahmeThe test is repeated after 50 hours of running the bath. With the low magnesium fluoride contents, the bath would have had a strong carburizing effect without the addition of melon. With the addition of melon, however, the bath is just as inert as when it was commissioned
Claims (4)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AT83107597T ATE18921T1 (en) | 1982-08-25 | 1983-08-02 | INERT SALT BATH FOR HEATING STEEL. |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19823231540 DE3231540A1 (en) | 1982-08-25 | 1982-08-25 | INERT SALT BATH FOR HEATING STEELS |
| DE3231540 | 1982-08-25 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0103717A1 true EP0103717A1 (en) | 1984-03-28 |
| EP0103717B1 EP0103717B1 (en) | 1986-04-02 |
Family
ID=6171642
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP83107597A Expired EP0103717B1 (en) | 1982-08-25 | 1983-08-02 | Inert salt bath for heating steel |
Country Status (12)
| Country | Link |
|---|---|
| EP (1) | EP0103717B1 (en) |
| JP (1) | JPS5938324A (en) |
| AT (1) | ATE18921T1 (en) |
| BR (1) | BR8304569A (en) |
| DE (2) | DE3231540A1 (en) |
| DK (1) | DK152224C (en) |
| ES (1) | ES8405084A1 (en) |
| IL (1) | IL69419A (en) |
| IN (1) | IN160848B (en) |
| TR (1) | TR21551A (en) |
| YU (1) | YU153383A (en) |
| ZA (1) | ZA835229B (en) |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE622802C (en) * | 1932-04-15 | 1935-12-06 | Emil Kleisinger Dr | Heating bath |
| DE1233423B (en) * | 1961-04-28 | 1967-02-02 | Ici Ltd | Process for the regeneration of a cyanide-free, molten salt bath used for the heat treatment of metals |
| DE1264475B (en) * | 1966-05-05 | 1968-03-28 | Degussa | Salt bath for the heat treatment of steel |
-
1982
- 1982-08-25 DE DE19823231540 patent/DE3231540A1/en not_active Withdrawn
-
1983
- 1983-07-08 JP JP58123556A patent/JPS5938324A/en active Granted
- 1983-07-15 YU YU01533/83A patent/YU153383A/en unknown
- 1983-07-18 ZA ZA835229A patent/ZA835229B/en unknown
- 1983-07-30 IN IN951/CAL/83A patent/IN160848B/en unknown
- 1983-08-02 TR TR21551A patent/TR21551A/en unknown
- 1983-08-02 AT AT83107597T patent/ATE18921T1/en not_active IP Right Cessation
- 1983-08-02 DE DE8383107597T patent/DE3362793D1/en not_active Expired
- 1983-08-02 EP EP83107597A patent/EP0103717B1/en not_active Expired
- 1983-08-03 IL IL69419A patent/IL69419A/en unknown
- 1983-08-23 DK DK385283A patent/DK152224C/en not_active IP Right Cessation
- 1983-08-24 BR BR8304569A patent/BR8304569A/en not_active IP Right Cessation
- 1983-08-24 ES ES525120A patent/ES8405084A1/en not_active Expired
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE622802C (en) * | 1932-04-15 | 1935-12-06 | Emil Kleisinger Dr | Heating bath |
| DE1233423B (en) * | 1961-04-28 | 1967-02-02 | Ici Ltd | Process for the regeneration of a cyanide-free, molten salt bath used for the heat treatment of metals |
| DE1264475B (en) * | 1966-05-05 | 1968-03-28 | Degussa | Salt bath for the heat treatment of steel |
Also Published As
| Publication number | Publication date |
|---|---|
| YU153383A (en) | 1985-12-31 |
| DE3231540A1 (en) | 1984-03-01 |
| IN160848B (en) | 1987-08-08 |
| IL69419A (en) | 1987-01-30 |
| BR8304569A (en) | 1984-04-03 |
| DK152224B (en) | 1988-02-08 |
| ATE18921T1 (en) | 1986-04-15 |
| DE3362793D1 (en) | 1986-05-07 |
| DK385283A (en) | 1984-02-26 |
| ES525120A0 (en) | 1984-05-16 |
| IL69419A0 (en) | 1983-11-30 |
| DK152224C (en) | 1988-06-27 |
| JPS5938324A (en) | 1984-03-02 |
| DK385283D0 (en) | 1983-08-23 |
| JPH0453925B2 (en) | 1992-08-28 |
| TR21551A (en) | 1984-09-27 |
| ES8405084A1 (en) | 1984-05-16 |
| EP0103717B1 (en) | 1986-04-02 |
| ZA835229B (en) | 1984-03-28 |
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