CH219219A - Process for hot hardening of steels. - Google Patents
Process for hot hardening of steels.Info
- Publication number
- CH219219A CH219219A CH219219DA CH219219A CH 219219 A CH219219 A CH 219219A CH 219219D A CH219219D A CH 219219DA CH 219219 A CH219219 A CH 219219A
- Authority
- CH
- Switzerland
- Prior art keywords
- steels
- sep
- alkali
- bath
- baths
- Prior art date
Links
- 229910000831 Steel Inorganic materials 0.000 title claims description 9
- 239000010959 steel Substances 0.000 title claims description 9
- 238000000034 method Methods 0.000 title claims description 8
- 229910052783 alkali metal Inorganic materials 0.000 claims description 6
- 238000010791 quenching Methods 0.000 claims description 5
- 230000000171 quenching effect Effects 0.000 claims description 5
- 239000003513 alkali Substances 0.000 claims description 4
- 150000001340 alkali metals Chemical class 0.000 claims description 4
- 150000002823 nitrates Chemical class 0.000 claims description 4
- 229910052784 alkaline earth metal Inorganic materials 0.000 claims description 3
- 150000001342 alkaline earth metals Chemical class 0.000 claims description 3
- -1 alkali metal nitrite Chemical class 0.000 claims description 2
- ZCDOYSPFYFSLEW-UHFFFAOYSA-N chromate(2-) Chemical class [O-][Cr]([O-])(=O)=O ZCDOYSPFYFSLEW-UHFFFAOYSA-N 0.000 claims description 2
- 150000001875 compounds Chemical class 0.000 claims description 2
- 230000001419 dependent effect Effects 0.000 claims 1
- 238000010438 heat treatment Methods 0.000 description 8
- XFXPMWWXUTWYJX-UHFFFAOYSA-N Cyanide Chemical compound N#[C-] XFXPMWWXUTWYJX-UHFFFAOYSA-N 0.000 description 6
- 229910002651 NO3 Inorganic materials 0.000 description 3
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 3
- 238000005261 decarburization Methods 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- 238000000354 decomposition reaction Methods 0.000 description 2
- 238000004880 explosion Methods 0.000 description 2
- 150000003839 salts Chemical class 0.000 description 2
- IOVCWXUNBOPUCH-UHFFFAOYSA-M Nitrite anion Chemical compound [O-]N=O IOVCWXUNBOPUCH-UHFFFAOYSA-M 0.000 description 1
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 150000002826 nitrites Chemical class 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- 238000005496 tempering Methods 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
- C21D1/18—Hardening; Quenching with or without subsequent tempering
- C21D1/19—Hardening; Quenching with or without subsequent tempering by interrupted quenching
- C21D1/20—Isothermal quenching, e.g. bainitic hardening
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Inorganic Compounds Of Heavy Metals (AREA)
Description
Verfahren zum Warmhärten von Stählen. Die vorliegende Erfindung bezieht sich auf ein Härteverfahren für Stähle aller Art, insbesondere Werkzeug- oder Vergütungs stähle bezw. aufgekohlte Einsatzstähle. Zwecks Warmhärtung hat man bisher diese Stähle in cyanidreichen Bädern auf höhere Temperaturen erhitzt und sodann in einem Salzbad von niedrigerer Temperatur ab geschreckt. Um in dem Erhitzungsbad die schädliche Entkohlung zu verhindern, muss ten dabei bisher höhere Cyanidgehalte vor gesehen werden.
Als Abschreckbäder kom men praktisch Alkalinitrate oder Gemische von diesen mit Alkalinitriten in Frage. Wenn man nunmehr :die Stähle aus dem cyanidhaltigen Anwärmebad in die nitrat- bezw. nitrithaltigen Abschreekbäder über führt, so treten leicht unliebsame Zersetzun- gen oder gar Explosionen auf, insbesondere wenn der Cyanidgehalt des Bades,
um die Entkohlung zu verhindern, hoch gewählt worden war, wie das bisher unerlässlich er- schien. Es lässt sich nicht vermeiden, dass bei der Überführung der Werkstücke aus dem Anwärmebad in das Abkühlbad anhaftende Salzmengen aus dem Erwärmungsbad in das Nitratbad gelangen. Da, wie erwähnt, hier bei Explosionen und Zersetzungen auftreten können, hat sich dieses Verfahren in der Praxis, nur schwer eingeführt.
Versuche, die üblichen, bekannten Anwärmebäder so zusam.- menzusetzen,-dass sie ganz oder nahezu frei von Cyanid waren, schienen aus dem Grunde nicht gangbar, weil sodann während des An wärmeres eine unerwünschte Entkohlung auf trat.
Es wurde nunmehr gefunden, dass es unter bestimmten Bedingungen möglich ist, das Anwärmen in einem cyanIdhaltigen Bad und das Abschrecken in einem nitrathaltigen Bad durchzuführen, ohne dass die oben ge nannten Nachteile in Erscheinung treten.
Das Verfahren der vorliegenden Erfin dung ist dadurch gekennzeichnet, dass man die Stähle zunächst in einem Schmelzbad, welches Alkalieyanid in Mengen von 1 bis 101'o, vorteilhaft 3 bis<B>-570,</B> sowie Verbin dungen der Erda.lkalimetalle enthält, auf Temperaturen von<B>700</B> bis 1000 erwärmt und sodann in einem zweiten Schmelzbad, welches. Nitrate der Alkalimetalle enthält, auf eine Temperatur zwischen 1.30 und 500 , vorteilhaft auf ea. 200 , abschreckt.
Die Erwärmungsbäder können z. B. Ha logenide und/oder Oxyde bezw. Karbonate der Erdalkali- und gegebenenfalls der Al kalimet.alle enthalten. Sehr gute Ergebnisse -werden erzielt mit Erwärmungsbädern von folgender Zusammensetzung:
EMI0002.0012
Na.CN <SEP> 3-5 <SEP> Teile
<tb> BaCl <SEP> 30-60 <SEP> "
<tb> NaCl <SEP> 10-30 <SEP> ,
<tb> KCl <SEP> 20-40 <SEP> , Für Abschreckbäder kommt z.
B. folgende Zusammensetzung in Betracht:
EMI0002.0015
NaN0ea. <SEP> 50 <SEP> Teile
<tb> KNO <SEP> ä <SEP> ", <SEP> 50 <SEP> " Dabei ist es mitunter von Vorteil, den Ab schreckbädern, die neben den Nitraten der Al- kalimetalle auch Alkalimetallnitrite enthal- ten können, geringe Mengen Chromate zu zufügen zur Stabilisierung der Bäder und zur Schonung der Baübehälter.
Process for hot hardening of steels. The present invention relates to a hardening process for steels of all types, in particular tool or tempering steels BEZW. carburized case-hardening steels. For the purpose of hot hardening, these steels have hitherto been heated to higher temperatures in cyanide-rich baths and then quenched in a salt bath at a lower temperature. In order to prevent the harmful decarburization in the heating bath, higher cyanide contents had to be seen in the past.
Practically alkali nitrates or mixtures of these with alkali nitrites come into consideration as quenching baths. If you now: the steels from the cyanide-containing heating bath in the nitrate or. passes over nitrite-containing sealing baths, unpleasant decomposition or even explosions can easily occur, especially if the cyanide content of the bath is
in order to prevent decarburization, it had been chosen to be high, as had previously seemed essential. It cannot be avoided that when the workpieces are transferred from the heating bath into the cooling bath, adhering amounts of salt from the heating bath get into the nitrate bath. Since, as mentioned, explosions and decomposition can occur here, this method has been introduced only with difficulty in practice.
Attempts to put together the usual, known heating baths so that they were completely or almost completely free of cyanide did not seem feasible for the reason that undesirable decarburization then occurred during the warmer period.
It has now been found that, under certain conditions, it is possible to carry out the heating in a bath containing cyanide and the quenching in a bath containing nitrate without the disadvantages mentioned above appearing.
The method of the present invention is characterized in that the steels are first placed in a molten bath containing alkali anide in quantities of 1 to 10 1, advantageously 3 to -570, and compounds of the alkaline earth metals contains, heated to temperatures of <B> 700 </B> to 1000 and then in a second molten bath, which. Nitrates containing alkali metals, quenched to a temperature between 1.30 and 500, advantageously to about 200.
The heating baths can e.g. B. Ha logenides and / or oxides BEZW. Carbonates of the alkaline earth metals and possibly the alkali metals all contain. Very good results are achieved with heating baths with the following composition:
EMI0002.0012
Na.CN <SEP> 3-5 <SEP> parts
<tb> BaCl <SEP> 30-60 <SEP> "
<tb> NaCl <SEP> 10-30 <SEP>,
<tb> KCl <SEP> 20-40 <SEP>, for quenching baths e.g.
B. the following composition is possible:
EMI0002.0015
NaN0ea. <SEP> 50 <SEP> parts
<tb> KNO <SEP> ä <SEP> ", <SEP> 50 <SEP>" It is sometimes advantageous to add small amounts of chromates to the quenching baths, which can contain alkali metal nitrites in addition to the nitrates of the alkali metals to be added to stabilize the baths and to protect the building containers.
Claims (1)
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE219219X | 1939-05-16 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CH219219A true CH219219A (en) | 1942-01-31 |
Family
ID=5831741
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CH219219D CH219219A (en) | 1939-05-16 | 1940-04-15 | Process for hot hardening of steels. |
Country Status (1)
| Country | Link |
|---|---|
| CH (1) | CH219219A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE931772C (en) * | 1952-12-14 | 1955-08-16 | Albert Erdmann & Co | Warming salt bath for carbonaceous, alloyed steels |
-
1940
- 1940-04-15 CH CH219219D patent/CH219219A/en unknown
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE931772C (en) * | 1952-12-14 | 1955-08-16 | Albert Erdmann & Co | Warming salt bath for carbonaceous, alloyed steels |
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