EP0103717B1 - Inertes Salzbad zum Erwärmen von Stählen - Google Patents

Inertes Salzbad zum Erwärmen von Stählen Download PDF

Info

Publication number
EP0103717B1
EP0103717B1 EP83107597A EP83107597A EP0103717B1 EP 0103717 B1 EP0103717 B1 EP 0103717B1 EP 83107597 A EP83107597 A EP 83107597A EP 83107597 A EP83107597 A EP 83107597A EP 0103717 B1 EP0103717 B1 EP 0103717B1
Authority
EP
European Patent Office
Prior art keywords
regenerator
polymeric
salt bath
bath
salt
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.)
Expired
Application number
EP83107597A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0103717A1 (de
Inventor
Friedrich-Wilhelm Dipl.-Ing. Eysell
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.)
Evonik Operations GmbH
Original Assignee
Degussa GmbH
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
Application filed by Degussa GmbH filed Critical Degussa GmbH
Priority to AT83107597T priority Critical patent/ATE18921T1/de
Publication of EP0103717A1 publication Critical patent/EP0103717A1/de
Application granted granted Critical
Publication of EP0103717B1 publication Critical patent/EP0103717B1/de
Expired legal-status Critical Current

Links

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 beam parts such as tools, the parts must be heated to the austenitizing temperature. In many cases, this heating takes place in salt baths. However, 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 may lead to melting and thus destruction of the workpieces at appropriate hardening temperatures. Nor should they have a corrosive effect.
  • Salt melts for heating steel parts to the austenitizing temperature 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, i.e. the melting point of the salt mixture. Melting of this type, which are made from very pure substances, generally meet 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' inertness is thus lost.
  • 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 not sufficient and in any case only temporarily, since methyl chloride must not be introduced into the melt during the treatment of workpieces.
  • regenerators are e.g. Silicon or silicon carbide.
  • the silicon generally fulfills the desired purpose, i.e. prevents decarburization, but occasionally the silicon is sintered onto the workpiece surface, which may result in irreparable damage. In addition, it generally forms 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 was achieved according to the invention by adding 0.01 to 2% by weight of a carbon and nitrogen-containing polymeric organic compound 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 f ⁇ / ! E! Amine, which can be prepared by heating melamine to temperatures of 500.degree.
  • 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.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Seasonings (AREA)
  • 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)
  • Electroplating And Plating Baths Therefor (AREA)
  • Heat Treatment Of Steel (AREA)
  • Cosmetics (AREA)
  • Nitrogen Condensed Heterocyclic Rings (AREA)
  • Lubricants (AREA)
  • Chemical Treatment Of Metals (AREA)
  • Heat Treatment Of Articles (AREA)
  • Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
EP83107597A 1982-08-25 1983-08-02 Inertes Salzbad zum Erwärmen von Stählen Expired EP0103717B1 (de)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT83107597T ATE18921T1 (de) 1982-08-25 1983-08-02 Inertes salzbad zum erwaermen von staehlen.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3231540 1982-08-25
DE19823231540 DE3231540A1 (de) 1982-08-25 1982-08-25 Inertes salzbad zum erwaermen von staehlen

Publications (2)

Publication Number Publication Date
EP0103717A1 EP0103717A1 (de) 1984-03-28
EP0103717B1 true EP0103717B1 (de) 1986-04-02

Family

ID=6171642

Family Applications (1)

Application Number Title Priority Date Filing Date
EP83107597A Expired EP0103717B1 (de) 1982-08-25 1983-08-02 Inertes Salzbad zum Erwärmen von Stählen

Country Status (12)

Country Link
EP (1) EP0103717B1 (da)
JP (1) JPS5938324A (da)
AT (1) ATE18921T1 (da)
BR (1) BR8304569A (da)
DE (2) DE3231540A1 (da)
DK (1) DK152224C (da)
ES (1) ES525120A0 (da)
IL (1) IL69419A (da)
IN (1) IN160848B (da)
TR (1) TR21551A (da)
YU (1) YU153383A (da)
ZA (1) ZA835229B (da)

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE622802C (de) * 1932-04-15 1935-12-06 Emil Kleisinger Dr Erhitzungsbad
DE1233423B (de) * 1961-04-28 1967-02-02 Ici Ltd Verfahren zum Regenerieren eines zyanid-freien, geschmolzenen, zur Waermebehandlung von Metallen benutzten Salzbades
DE1264475B (de) * 1966-05-05 1968-03-28 Degussa Salzbad zur Waermebehandlung von Stahl

Also Published As

Publication number Publication date
JPH0453925B2 (da) 1992-08-28
ES8405084A1 (es) 1984-05-16
ATE18921T1 (de) 1986-04-15
IL69419A0 (en) 1983-11-30
IN160848B (da) 1987-08-08
DE3362793D1 (en) 1986-05-07
IL69419A (en) 1987-01-30
EP0103717A1 (de) 1984-03-28
BR8304569A (pt) 1984-04-03
DK385283A (da) 1984-02-26
TR21551A (tr) 1984-09-27
YU153383A (en) 1985-12-31
DK385283D0 (da) 1983-08-23
DE3231540A1 (de) 1984-03-01
ZA835229B (en) 1984-03-28
DK152224C (da) 1988-06-27
DK152224B (da) 1988-02-08
JPS5938324A (ja) 1984-03-02
ES525120A0 (es) 1984-05-16

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