EP0449030A2 - Procédé pour le recuit de pièces en acier - Google Patents

Procédé pour le recuit de pièces en acier Download PDF

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Publication number
EP0449030A2
EP0449030A2 EP91103759A EP91103759A EP0449030A2 EP 0449030 A2 EP0449030 A2 EP 0449030A2 EP 91103759 A EP91103759 A EP 91103759A EP 91103759 A EP91103759 A EP 91103759A EP 0449030 A2 EP0449030 A2 EP 0449030A2
Authority
EP
European Patent Office
Prior art keywords
annealing
oxygen
chamber
annealing material
free
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.)
Withdrawn
Application number
EP91103759A
Other languages
German (de)
English (en)
Other versions
EP0449030A3 (en
Inventor
Alexander Dipl.-Ing. Jurmann
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.)
Linde GmbH
Original Assignee
Linde 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 Linde GmbH filed Critical Linde GmbH
Publication of EP0449030A2 publication Critical patent/EP0449030A2/fr
Publication of EP0449030A3 publication Critical patent/EP0449030A3/de
Withdrawn legal-status Critical Current

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    • 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
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
    • C21D9/54—Furnaces for treating strips or wire
    • C21D9/56—Continuous furnaces for strip or wire
    • C21D9/561—Continuous furnaces for strip or wire with a controlled atmosphere or vacuum
    • 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
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length

Definitions

  • the invention relates to methods for the annealing of steel annealing material, in particular stainless steel, in continuous systems under protective gas, the annealing material being successively heated, annealed and cooled again in the protective gas atmosphere
  • the annealing of steel annealing material is often carried out in a continuous process in continuous plants or furnaces under a suitable protective gas, often gas atmospheres with a high hydrogen content.
  • a suitable protective gas often gas atmospheres with a high hydrogen content.
  • the problem here is that, according to new knowledge, boron contained in the annealing material is oxidized out of it during the annealing process. This boron oxide is subsequently reflected in the form of white dust in the downstream coolers, which are used to cool the annealing material, and reduces their cooling capacity so drastically over the course of a few weeks that production in the plant is interrupted and the coolers have to be replaced or cleaned . This results in a loss of production of at least one working day.
  • the object of the present invention is therefore to further reduce or completely eliminate the problem of white dust which leads to production downtimes in the case of continuous heat treatments.
  • This object is achieved according to the present invention in that the annealed material is subjected to a deoxidizing pretreatment before the actual annealing process, which at least largely removes the oxygen adsorbed on the surface of the annealed material and any oxygen compounds present on the surface.
  • said white dust consists essentially of boron oxides, which arise from the fact that the boron contained in the annealing material reacts with oxygen or oxygen compounds also present in the annealing system during the annealing process.
  • This "oxygen supply" in the annealing plant is probably caused by said adsorptive coating of the annealing material with oxygen and by the alloy oxides present in a surface layer, which are present above all in the case of passivated annealing material. The latter is particularly the case with stainless steel strips.
  • this process is now prevented by a deoxidizing treatment of the annealing material preceding the annealing.
  • the deoxidation of the annealing material can be brought about by various methods, for example by passing through an upstream heat chamber with an independent protective gas atmosphere separate from the annealing system or passing through a chamber at low pressure.
  • the deoxidizing pretreatment according to the invention consists in subjecting the annealing material to pickling with subsequent cleaning, this being carried out in a largely oxygen-free chamber
  • the execution in an oxygen-free atmosphere prevents the annealing material from being reloaded with oxygen after the pickling.
  • said oxygen-free chamber is produced by purging the chamber with oxygen-free gases, nitrogen or argon preferably being used on account of their inert and unproblematic properties and for reasons of cost.
  • An oxygen content of ⁇ 1 vpm is preferably maintained by means of oxygen monitoring.
  • the deoxidizing pickling is carried out by passing the annealing material through a conventional or electrolytic pickling bath, with an exposure time of at least 3 seconds being maintained.
  • a further, particularly effective process variant is that deoxidizing pretreatment is carried out by subjecting the annealing material to inductive heating, which is carried out particularly advantageously in a hydrogen-purged, oxygen-free chamber.
  • This process variant is particularly advantageous for predominantly adsorbed oxygen on the annealing material, since the quick, inductive heating achieves good and rapid oxygen desorption, which is additionally supported by the hydrogen atmosphere and its reducing effect.
  • a glow system suitable for carrying out the invention is characterized in that an essentially closed chamber provided with a gas supply line is arranged in front of the inlet zone into the glow system, said chamber containing a pickling bath, a cleaning station and transport devices for the annealing material through the chamber and its Includes facilities.
  • the second variant of the method is characterized by a device for inductive heating of the annealing material located in the chamber and also by corresponding transport devices.
  • the drawing shows the inlet area of a strip annealing plant with an upstream deoxidation chamber according to the invention.
  • the annealed material in the example described thus consists of a continuous steel strip 1 which is conveyed by means of rollers 2, 3, 4.
  • the steel strip 1 first runs into a chamber 5 and is deflected there by the rollers 2 and 3 in such a way that it is introduced into a pickling bath 6, which it leaves after the next roller 4 has been rotated.
  • the pickling bath 6 is followed by a cleaning station 7, after which the steel strip 1 passes from the chamber 5 into the actual annealing system, which adjoins the chamber 5 with its inlet tunnel 8.
  • the chamber 5 has it
  • the above-mentioned second method variant is shown in the drawing with the omission of the pickling bath 6 and the cleaning station 7 and the arrangement of an induction heating device between the rollers 3 and 4, for example.
  • nitrogen is now supplied to the chamber 5 via the gas feed line 9, for example, whereby the air and in particular the oxygen contained therein are displaced from the chamber 5.
  • the oxygen content in the chamber 5 is monitored by the control device 12, the nitrogen supply being controlled by the control unit 12 so that a certain oxygen content is no longer exceeded. This is preferably below 1 vpm.
  • This oxygen displacement serves to ensure that a steel strip deoxidized in the chamber 5 according to the invention can no longer be reloaded with oxygen or oxygen compounds before the annealing.
  • the deoxidation ie the removal of adsorbed oxygen or oxygen compounds present on the surface, takes place in the chamber 5 in that, according to the first method variant, the steel strip 1 is guided through the pickling bath 5 arranged in this chamber.
  • the pickling bath 5 contains a pickling acid which is also known from the passivation of steel material, for example 10% nitric acid.
  • a pickling acid which is also known from the passivation of steel material, for example 10% nitric acid.
  • the purpose aimed at with the present invention is achieved and the Oxygen on the steel strip is reduced so much that the formation of white dust is significantly reduced.
  • the steel strip is to be cleaned in order to remove the stain remaining on the strip, which can be accomplished by stripping and drying the steel strip.

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)
  • Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
  • Heat Treatment Of Strip Materials And Filament Materials (AREA)
EP19910103759 1990-03-29 1991-03-12 Process for annealing steel material Withdrawn EP0449030A3 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE4010102 1990-03-29
DE4010102A DE4010102A1 (de) 1990-03-29 1990-03-29 Verfahren zum gluehen von staehlernem gluehgut

Publications (2)

Publication Number Publication Date
EP0449030A2 true EP0449030A2 (fr) 1991-10-02
EP0449030A3 EP0449030A3 (en) 1993-01-27

Family

ID=6403335

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19910103759 Withdrawn EP0449030A3 (en) 1990-03-29 1991-03-12 Process for annealing steel material

Country Status (4)

Country Link
US (1) US5167735A (fr)
EP (1) EP0449030A3 (fr)
JP (1) JPH05345912A (fr)
DE (1) DE4010102A1 (fr)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5259935A (en) * 1991-05-03 1993-11-09 The Boc Group, Inc. Stainless steel surface passivation treatment
US5614039A (en) * 1995-09-29 1997-03-25 The Boc Group, Inc. Argon employing heat treating process
US6551929B1 (en) * 2000-06-28 2003-04-22 Applied Materials, Inc. Bifurcated deposition process for depositing refractory metal layers employing atomic layer deposition and chemical vapor deposition techniques
DE102004001980A1 (de) * 2003-01-14 2004-07-22 Ruag Ammotec Gmbh Treibladung
JP2005120448A (ja) * 2003-10-17 2005-05-12 Chugai Ro Co Ltd 光輝焼鈍炉の制御方法

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1273553B (de) * 1962-04-06 1968-07-25 Heurtey Sa Einrichtung zur fortlaufenden Vorbehandlung von Baendern aus Stahl oder aehnlichem Metall fuer das anschliessende UEberziehen der Baender mit anderen Metallen in Metall-oder Metallsalzbaedern
US4186038A (en) * 1976-04-15 1980-01-29 General Electric Company Method of producing silicon-iron sheet material with boron addition, and product
US4116730A (en) * 1977-03-07 1978-09-26 General Electric Company Silicon-iron production and composition and process therefor
IT1116679B (it) * 1977-12-16 1986-02-10 Centro Speriment Metallurg Perfezionamento nel procedimento di produzione di lamierino di acciaio al silicio per impieghi magnetici
US4478653A (en) * 1983-03-10 1984-10-23 Armco Inc. Process for producing grain-oriented silicon steel
US4713154A (en) * 1985-08-08 1987-12-15 Kawasaki Steel Corporation Continuous annealing and pickling method and apparatus for steel strips
BE903804A (fr) * 1985-12-05 1986-06-05 Centre Rech Metallurgique Procede de traitement d'une bande metallique mince laminee a chaud.

Also Published As

Publication number Publication date
US5167735A (en) 1992-12-01
DE4010102A1 (de) 1991-10-02
EP0449030A3 (en) 1993-01-27
JPH05345912A (ja) 1993-12-27

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