EP0814180A1 - Procédé de traitement de surfaces en acier inoxydable - Google Patents

Procédé de traitement de surfaces en acier inoxydable Download PDF

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Publication number
EP0814180A1
EP0814180A1 EP97109613A EP97109613A EP0814180A1 EP 0814180 A1 EP0814180 A1 EP 0814180A1 EP 97109613 A EP97109613 A EP 97109613A EP 97109613 A EP97109613 A EP 97109613A EP 0814180 A1 EP0814180 A1 EP 0814180A1
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EP
European Patent Office
Prior art keywords
treated
pickling solution
pickling
treatment
container
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.)
Ceased
Application number
EP97109613A
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German (de)
English (en)
Inventor
Ralf Waldmann
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.)
Keramchemie GmbH
Original Assignee
Keramchemie 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
Priority claimed from DE1996124436 external-priority patent/DE19624436A1/de
Application filed by Keramchemie GmbH filed Critical Keramchemie GmbH
Publication of EP0814180A1 publication Critical patent/EP0814180A1/fr
Ceased legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25F—PROCESSES FOR THE ELECTROLYTIC REMOVAL OF MATERIALS FROM OBJECTS; APPARATUS THEREFOR
    • C25F1/00—Electrolytic cleaning, degreasing, pickling or descaling
    • C25F1/02—Pickling; Descaling
    • C25F1/04—Pickling; Descaling in solution
    • C25F1/06—Iron or steel
    • 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
    • C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
    • C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
    • C23G1/02—Cleaning or pickling metallic material with solutions or molten salts with acid solutions
    • C23G1/08—Iron or steel

Definitions

  • the invention relates to a method for the surface treatment of existing, in particular band-shaped, material to be treated, in which the material to be treated is treated with a pickling solution in at least one container and then rinsed.
  • Stainless steels these are non-rusting or rust-resistant, alloyed steels, must have a clean metallic surface with a low roughness depth in order to achieve optimum chemical resistance.
  • the scale layers and tarnish colors created during the hot forming or heat treatment must be removed, since they impair the formation of a corrosion-inhibiting passive layer.
  • the scale layers and tarnishing colors are also removed by a pickling process on stainless steels. In such a pickling process, however, it must be taken into account that the base metal is relatively resistant to an acid attack and that if the acid is attacked to a greater extent, the surface is not removed uniformly, but rather in places.
  • the existing scale layer adheres relatively strongly to the base metal and is therefore considerably more difficult and can only be removed with increased effort.
  • the scale layer also contains oxides of the alloy metals and mixed oxides in addition to the iron oxides.
  • the structural condition which can be austenitic, ferritic, martensitic, austenitic-ferritic and ferritic-martensitic, is also important for the pickling properties of stainless steels. Taking these circumstances into account, a strip made of stainless steel is first mechanically descaled by a blasting and brushing process.
  • the strip is then pickled in several containers with different pickling solutions, such as sulfuric acid, hydrofluoric acid and additives without nitric acid, mixed acid (hydrofluoric acid-nitric acid mixture) or in electrolytic baths of sulfuric acid or neutral salts. After sufficient rinsing, the stainless steel band is then passivated.
  • pickling solutions such as sulfuric acid, hydrofluoric acid and additives without nitric acid, mixed acid (hydrofluoric acid-nitric acid mixture) or in electrolytic baths of sulfuric acid or neutral salts.
  • pickling stainless steel items to be treated is relatively complex. This also applies to the reprocessing or regeneration of used pickling solutions. It should also be borne in mind that sludge is produced during the treatment or regeneration of the pickling solutions, which requires valuable landfill space. In addition, the pickling processes previously used for pickling stainless steel do not work without waste water.
  • the invention is therefore based on the object of demonstrating a method for the surface treatment of material consisting of stainless steel, in particular in the form of a strip, in which the mechanical pretreatment can be omitted, a relatively inexpensive acid with particularly good regenerability can be used and which works without waste water.
  • a relatively inexpensive acid with particularly good regenerability can be used and which works without waste water.
  • hydrochloric acid is generally known as a pickling solution, it has not yet been used for pickling stainless steel. This has to do with the fact that when pickling stainless steel using hydrochloric acid there is a risk of so-called cracking and / or intergranular corrosion, since the fluorides that form normally attack the stainless steel.
  • Spray pickling with a solution containing only hydrochloric acid as the acid has a relatively high efficiency.
  • the spraying process results in a particularly smooth surface of the material to be treated, which does not exceed a roughness of more than 3 ⁇ m.
  • the pickling solution containing only hydrochloric acid as an acid is relatively inexpensive, easy to regenerate and enables a wastewater-free surface treatment.
  • this belt 1 is first passed through a treatment tank 2, in which the belt is electrolytically pickled by means of a solution containing hydrochloric acid as the only acid.
  • This electrolytic pickling can be referred to as a kind of pre-pickling, so that mechanical descaling carried out previously can be dispensed with.
  • the treatment container 2 is enlarged, but is also only shown schematically.
  • the treatment container 2 consists of a plurality of compartments or electrolysis cells 3 with the individual electrodes 4 which are formed one behind the other.
  • the individual electrodes 4 in the successive electrolysis cells 3 alternately form the anode and the cathode, while the strip 1 then in the corresponding electrolytic cells 3 there is also alternating the cathode and the anode, ie alternate cathodic and anodic pickling takes place here.
  • the polarity of the electrodes 4 of the successive compartments or electrolysis cells 3 can be changed in a relatively short period of time, for example within 1 to 2 seconds, by means of a pole switch or pole reversing switch known per se.
  • Fig. 3 of the drawing shows the treatment container 2, in which the pickling is carried out using the so-called middle conductor method.
  • the treatment tank 2 is also in individual electrolysis cells 3 or compartments with mutual Arrangement of the cathodes and anodes divided. This also leads to the fact that the steel strip 1 is subjected to a repeated change of polarity when it is pulled through, as a result of which the hydrogen loading and the associated pickling brittleness are avoided.
  • the changing polarity of the electrodes prevents the release of chlorine gases.
  • the treatment container 2 is filled with a pickling solution which only contains hydrochloric acid as acid, the pickling solution being about 70-140 grams, advantageously about 90-120 grams, of free hydrochloric acid per liter of pickling solution.
  • the temperature of the pickling solution is approximately 50-95 ° C, advantageously approximately 70-85 ° C.
  • the current density in the electrolytic treatment is about 3 to 40 A / dm 2 , advantageously about 20 A / dm 2 .
  • the pickling solution, which acts as an electrolyte, should have an iron chloride content of about 30 - 200 grams per liter.
  • the steel strip 1 arrives in a further treatment tank 5, which is designed as a dip pickling tank and which also receives a pickling solution containing only hydrochloric acid. It is advantageous here if the pickling solution is guided in countercurrent to the direction of movement of the steel strip 1. In this treatment tank 5 too, the pickling solution has approximately the same concentration and the same temperature as in the treatment tank 2.
  • a treatment container (not shown) can be arranged between the treatment container 2 and the treatment container 5 be, which is designed as a so-called spray treatment container 6, as it is arranged downstream of the treatment container 5 in the present case.
  • the steel strip 1 is sprayed under pressure by means of a pickling solution likewise exclusively containing hydrochloric acid.
  • the pickling solution sprayed on here is also identical to the pickling solutions of treatment tanks 2 and 5.
  • the steel strip 1 arrives at a rinsing container 7, in which all residual chlorides still on the steel strip 1 are removed.
  • Demineralized water is advantageously used in the rinsing container 7.
  • the rinsing container 7 can either be designed as a dip and / or spray container.
  • the steel strip 1 is then passed through a passivation system 8, in which hydrogen peroxide is preferably applied. After that, the steel strip 1 only has to be dried.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Electrochemistry (AREA)
  • Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
  • ing And Chemical Polishing (AREA)
EP97109613A 1996-06-19 1997-06-13 Procédé de traitement de surfaces en acier inoxydable Ceased EP0814180A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
DE1996124436 DE19624436A1 (de) 1996-06-19 1996-06-19 Verfahren zur Oberflächenbehandlung von aus Edelstahl bestehendem Behandlungsgut
DE19624436 1996-06-19
DE19721135 1997-05-21
DE19721135A DE19721135A1 (de) 1996-06-19 1997-05-21 Verfahren zur Oberflächenbehandlung von aus Edelstahl bestehendem Behandlungsgut

Publications (1)

Publication Number Publication Date
EP0814180A1 true EP0814180A1 (fr) 1997-12-29

Family

ID=26026713

Family Applications (1)

Application Number Title Priority Date Filing Date
EP97109613A Ceased EP0814180A1 (fr) 1996-06-19 1997-06-13 Procédé de traitement de surfaces en acier inoxydable

Country Status (4)

Country Link
US (1) US5840173A (fr)
EP (1) EP0814180A1 (fr)
JP (1) JPH1060697A (fr)
TW (1) TW382640B (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0972854A2 (fr) * 1998-07-15 2000-01-19 Andritz-Patentverwaltungs-Gesellschaft m.b.H. Procédé de dècapage d'acier inoxydable

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
IT1302202B1 (it) 1998-09-11 2000-07-31 Henkel Kgaa Processo di decapaggio elettrolitico con soluzioni esenti da acidonitrico.
EP3029164B1 (fr) * 2014-12-02 2020-06-17 CMI UVK GmbH Procédé de traitement d'une bande d'acier inoxydable, notamment pour un traitement de décapage
ES2742827T3 (es) * 2014-12-02 2020-02-17 Cmi Uvk Gmbh Método y sistema de tratamiento de una banda de acero al carbono, especialmente para el decapado

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB539424A (en) * 1940-03-05 1941-09-10 Sharon Steel Corp Method and apparatus for electrically pickling stainless steels
JPS5074529A (fr) * 1973-11-05 1975-06-19
JPS5093830A (fr) * 1973-12-25 1975-07-26
JPS50140335A (fr) * 1974-04-30 1975-11-11
EP0209168A1 (fr) * 1985-07-12 1987-01-21 N.V. Bekaert S.A. Procédé et dispositif pour le nettoyage par décapage électrochimique en utilisant un courant alternatif d'une fréquence spécifiée
JPS6333600A (ja) * 1986-07-29 1988-02-13 Nippon Steel Corp 鋼ストリツプの電解酸洗法
EP0770707A1 (fr) * 1995-09-01 1997-05-02 Keramchemie GmbH Procédé de fabrication en continu de bandes laminées au froid

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5767133A (en) * 1980-10-09 1982-04-23 Nippon Steel Corp Continuous annealing installation having adjusting device for strip surface
FR2683551B1 (fr) * 1991-11-07 1994-09-16 Ugine Sa Procede de decapage de materiaux en acier en continu sur une ligne de traitement.
TW296988B (fr) * 1993-09-17 1997-02-01 Hitachi Ltd

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB539424A (en) * 1940-03-05 1941-09-10 Sharon Steel Corp Method and apparatus for electrically pickling stainless steels
JPS5074529A (fr) * 1973-11-05 1975-06-19
JPS5093830A (fr) * 1973-12-25 1975-07-26
JPS50140335A (fr) * 1974-04-30 1975-11-11
EP0209168A1 (fr) * 1985-07-12 1987-01-21 N.V. Bekaert S.A. Procédé et dispositif pour le nettoyage par décapage électrochimique en utilisant un courant alternatif d'une fréquence spécifiée
JPS6333600A (ja) * 1986-07-29 1988-02-13 Nippon Steel Corp 鋼ストリツプの電解酸洗法
EP0770707A1 (fr) * 1995-09-01 1997-05-02 Keramchemie GmbH Procédé de fabrication en continu de bandes laminées au froid

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
CHEMICAL ABSTRACTS, vol. 84, no. 18, 3 May 1976, Columbus, Ohio, US; abstract no. 125264e, NIPON STEEL: "Removing sclale from stainless steel" page 223; column R; XP002041351 *
CHEMICAL ABSTRACTS, vol. 84, no. 18, 3 May 1976, Columbus, Ohio, US; abstract no. 125290k, NIPPON STEEL: "DESCALING OF STAINLESS STEEL" page 225; column R; XP002041350 *
CHEMICAL ABSTRACTS, vol. 84, no. 20, 17 May 1976, Columbus, Ohio, US; abstract no. 139356y, NIPPON STEEL: "DESCALING OF STAINLESS STEEL" page 255; column R; XP002041349 *
PATENT ABSTRACTS OF JAPAN vol. 012, no. 242 (C - 510) 8 July 1988 (1988-07-08) *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0972854A2 (fr) * 1998-07-15 2000-01-19 Andritz-Patentverwaltungs-Gesellschaft m.b.H. Procédé de dècapage d'acier inoxydable
EP0972854A3 (fr) * 1998-07-15 2000-07-19 Andritz-Patentverwaltungs-Gesellschaft m.b.H. Procédé de dècapage d'acier inoxydable

Also Published As

Publication number Publication date
TW382640B (en) 2000-02-21
US5840173A (en) 1998-11-24
JPH1060697A (ja) 1998-03-03

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