EP0471662B1 - Process for pickling stainless steel - Google Patents
Process for pickling stainless steel Download PDFInfo
- Publication number
- EP0471662B1 EP0471662B1 EP91890156A EP91890156A EP0471662B1 EP 0471662 B1 EP0471662 B1 EP 0471662B1 EP 91890156 A EP91890156 A EP 91890156A EP 91890156 A EP91890156 A EP 91890156A EP 0471662 B1 EP0471662 B1 EP 0471662B1
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- EP
- European Patent Office
- Prior art keywords
- pickling
- sulfuric acid
- neutral electrolyte
- acid
- pretreatment
- 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 - Lifetime
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- 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
Definitions
- the invention relates to a method for pickling stainless steel, preferably stainless steel hot strip, in which the stainless steel is subjected to electrolytic pickling with neutral electrolyte, as well as an aftertreatment with mixed acid, nitric acid or a mixture of iron fluoride (FeF3) and hydrofluoric acid, which is carried out using electricity or can be done without power.
- a method for pickling stainless steel preferably stainless steel hot strip
- the stainless steel is subjected to electrolytic pickling with neutral electrolyte, as well as an aftertreatment with mixed acid, nitric acid or a mixture of iron fluoride (FeF3) and hydrofluoric acid, which is carried out using electricity or can be done without power.
- the material is pickled in aqueous solutions of neutral alkali salts of mineral acids and then in aqueous solutions of mineral acids, preferably sulfuric acid, both treatment stages being electrolytic, i.e. done using electricity.
- An aqueous sodium sulfate solution is preferably used as the neutral electrolyte and the current densities are in the range between 5 and 15 A / dm 2. Higher current densities are possible in principle, but are not used due to the higher voltage required due to the poor conductivity of the stainless steel.
- mixed acid preferably includes a mixture of nitric acid and hydrofluoric acid.
- Current pickling in mixed acid is not common because of the problems with the electrode material, which is said to be resistant to current and acid.
- the pickling time in neutral electrolyte and mixed acid is approximately 120 seconds for approximately 3 mm thick stainless steel hot strip. Approx. 240 seconds for 6 mm thick stainless steel hot strip and even up to 270 seconds for ferritic hot strip of quality AISI 430 and more rational production, the demand for shorter pickling processes persisted.
- Japanese patent application No. 55 - 50 468 describes a purely chemical process for pickling chromium-containing stainless steel. In each case, it is initially electrolessly pickled in hydrochloric acid or sulfuric acid and then aftertreated to achieve a particular degree of whiteness with Fe (NO3) 3, with Fe2 (SO4) 3 or (NH4) 2S2O8 solution. The scale is removed and a bare, white surface is achieved without electricity and only by the oxidizing aftertreatment with salts of trivalent iron or with persulfates.
- the method mentioned can only be carried out with ferritic stainless steel, since austenitic stainless steels also contain chromium, but because of the additional alloy element nickel, the scale is constructed in a completely different way and cannot be removed solely by the pickling method described.
- the object of the invention is therefore a method of the type mentioned in the introduction, in which a reduction in the duration of treatment can be achieved while maintaining or even increasing the good pickling effect achieved to date.
- the object is achieved in that the pickling with neutral electrolyte precedes a pretreatment with sulfuric acid.
- the pretreatment with sulfuric acid is carried out at a temperature of 60 to 95 ° C, preferably between 75 and 85 ° C.
- the concentration of sulfuric acid is between 200 and 500 g / l, preferably between 300 and 400 g / l.
- the pretreatment with sulfuric acid is between 5 and 30% of the total treatment time, and the pickling in neutral electrolyte is between 25 and 50% of the total treatment time.
- the advantage of the three-stage pickling process according to the invention is that it can be used both for austenitic (AISI 304 and 316) and for ferritic stainless steel grades (AISI 430) and the pickling time is greatly reduced for both stainless steel grades.
- the short pretreatment of the stainless steel according to the invention with preferably dilute sulfuric acid before entering the neutral electrolyte can reduce the pickling time in the neutral electrolyte and in the subsequent mixed acid, as a result of which a substantial increase in performance is achieved in the existing systems with the same space requirement.
- newly designed systems with the same performance as existing systems can be dimensioned much smaller and therefore economically more economical and cost-saving.
- the pickling effect can also be improved in the process according to the invention by brushing the pickled material between the individual treatments.
- Brushing can take place either between the pretreatment with sulfuric acid and the neutral electrolyte stain, between neutral electrolyte stain and the aftertreatment in mixed acid or on both occasions as well as in the rinse after the treatment with mixed acid. This brushing has no effect on the pickling time, but reduces the acid consumption because loosely adhering scale is removed.
- a stainless steel hot strip of quality AISI 304, 3.1 mm thick was initially in sulfuric acid, with a concentration of 350g / l a temperature of 85 ° C, and then in mixed acid with a concentration of 25g / l HF and 150 g / l HNO3, at a temperature of 55 ° C, pickling, the pickling time a total of 180 sec. and the ratio of pickling times 2: 1 was.
- neutral electrolyte here Na2SO4 with a concentration of 150 g / l
- the pickling time could be reduced to 120 seconds, the ratio of the treatment times now being 1: 1.
- the polarization of the band changed from anodic, with a current density of 10A / dm2, to cathodic, with 20A / dm2, and then back to anodic with 10A / dm2.
- the temperature of the neutral electrolytes was 80 ° C. After installing a sulfuric acid pretreatment stage, the subsequent pickling time in the neutral electrolyte could be shortened and the total pickling time reduced to a total of 90 seconds, the ratio of the pickling times in the individual steps now being 1: 2: 4.
- the concentrations and temperatures also corresponded to the values given above in the method according to the invention.
- a stainless steel hot strip of quality AISI 316 L, 6 mm thick was subjected to the same three pickling processes as in exemplary embodiment 1, with the same process parameters.
- the pickling time could be reduced from 360 seconds in sulfuric acid and mixed acid to 240 seconds in neutral electrolyte and mixed acid and further to 140 seconds in the case of pretreatment with sulfuric acid stain with neutral electrolyte and aftertreatment with mixed acid.
- the pickling times for the first two pickling processes were each about 270 seconds.
- the treatment time could be reduced to 210 seconds.
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
- Treatment Of Steel In Its Molten State (AREA)
- Heat Treatment Of Strip Materials And Filament Materials (AREA)
- Chemical Treatment Of Metals (AREA)
- Heat Treatment Of Steel (AREA)
Abstract
Description
Die Erfindung betrifft ein Verfahren zum Beizen von Edelstahl, vorzugsweise von Edelstahl-Warmband, bei welchem der Edelstahl einer elektrolytischen Beize mit Neutralelektrolyt, sowie einer Nachbehandlung mit Mischsäure, Salpetersäure oder einer Mischung von Eisenfluorid (FeF3) und Flußsäure unterzogen wird, die unter Stromanwendung oder stromlos erfolgen kann.The invention relates to a method for pickling stainless steel, preferably stainless steel hot strip, in which the stainless steel is subjected to electrolytic pickling with neutral electrolyte, as well as an aftertreatment with mixed acid, nitric acid or a mixture of iron fluoride (FeF3) and hydrofluoric acid, which is carried out using electricity or can be done without power.
In der edelstahlerzeugenden Industrie haben sich in den letzten Jahren Verfahren zum Beizen von Edelstahl nach dem Neutralelektrolytprozeß vermehrt durchgesetzt. Wie beispielsweise in der AT-PS 252685 beschrieben ist, wird das Material hierbei in wässrigen Lösungen neutraler Alkalisalze von Mineralsäuren und anschließend in wässrigen Lösungen von Mineralsäuren, vorzugsweise Schwefelsäure, gebeizt, wobei beide Behandlungsstufen elektrolytisch, d.h. unter Stromanwendung erfolgen. Als Neutralelektrolyt kommt vorzugsweise eine wässrige Natriumsulfatlösung zur Anwendung und die Stromdichten liegen im Bereich zwischen 5 und 15 A/dm². Höhere Stromdichten sind prinzipiell möglich, werden aber wegen der höheren benötigten Spannung durch die schlechte Leitfähigkeit des Edelstahls nicht angewandt. Wie aus der AT-PS 387406 bekannt ist, kann die anschließende Nachbehandlung in der Säure, hier vorzugsweise Mischsäure, stromlos durchgeführt werden. Der Ausdruck Mischsäure umfaßt vorzugsweise eine Mischung von Salpetersäure und Flußsäure. Ein Beizen unter Strom in Mischsäure ist wegen der Probleme mit dem Elektrodenmaterial, das gegen Strom und gegen die Säure beständig sein soll, nicht üblich.In the stainless steel producing industry, processes for pickling stainless steel using the neutral electrolyte process have become increasingly popular in recent years. As described, for example, in AT-PS 252685, the material is pickled in aqueous solutions of neutral alkali salts of mineral acids and then in aqueous solutions of mineral acids, preferably sulfuric acid, both treatment stages being electrolytic, i.e. done using electricity. An aqueous sodium sulfate solution is preferably used as the neutral electrolyte and the current densities are in the range between 5 and 15 A / dm 2. Higher current densities are possible in principle, but are not used due to the higher voltage required due to the poor conductivity of the stainless steel. As is known from AT-PS 387406, the subsequent aftertreatment in the acid, here preferably mixed acid, can be carried out without current. The term mixed acid preferably includes a mixture of nitric acid and hydrofluoric acid. Current pickling in mixed acid is not common because of the problems with the electrode material, which is said to be resistant to current and acid.
Trotz der guten Wirkung dieser bekannten Verfahren in Bezug auf den Beizeffekt, hat es sich als nachteilig herausgestellt, daß diese Verfahren eine relativ lange Behandlungszeit benötigen. Beispielsweise beträgt die Beizzeit in Neutralelektrolyt und Mischsäure für etwa 3 mm dickes Edelstahl-Warmband etwa 120 sec. Für 6 mm starkes Edelstahl-Warmband etwa 240 sec. und für ferritisches Warmband der Qualität AISI 430 sogar bis 270 sec., sodaß im Zuge einer schnelleren und rationelleren Produktion die Forderung nach kürzeren Beizverfahren bestehen blieb.Despite the good effect of these known methods with regard to the pickling effect, it has turned out to be disadvantageous that these methods require a relatively long treatment time. For example, the pickling time in neutral electrolyte and mixed acid is approximately 120 seconds for approximately 3 mm thick stainless steel hot strip. Approx. 240 seconds for 6 mm thick stainless steel hot strip and even up to 270 seconds for ferritic hot strip of quality AISI 430 and more rational production, the demand for shorter pickling processes persisted.
Die japanische Patentanmeldung Nr. 55 - 50 468 beschreibt ein rein chemisches Verfahren zum Beizen von chromhältigem Edelstahl. Dabei wird jeweils stromlos vorerst in Salzsäure oder Schwefelsäure gebeizt und anschließend zum Erzielen eines besonderen Weißgrades mit Fe(NO₃)₃, mit Fe₂(SO₄)₃ oder (NH₄)₂S₂O₈- Lösung nachbehandelt. Die Entfernung des Zunders und die Erzielung einer blanken, weißen Oberfläche wird dabei ohne Strom und nur durch die oxydierende Nachbehandlung mit Salzen von dreiwertigem Eisen bzw. mit Persulfaten erzielt. Das angesprochene Verfahren ist jedoch nur bei ferritischem Edelstahl durchführbar, da austenitische Edelstähle zwar auch Chrom enthalten, wegen des zusätzlichen Legierungselementes Nickel der Zunder aber ganz anders aufgebaut ist und allein durch diese beschriebene Beizmethode nicht entfernt werden kann.Japanese patent application No. 55 - 50 468 describes a purely chemical process for pickling chromium-containing stainless steel. In each case, it is initially electrolessly pickled in hydrochloric acid or sulfuric acid and then aftertreated to achieve a particular degree of whiteness with Fe (NO₃) ₃, with Fe₂ (SO₄) ₃ or (NH₄) ₂S₂O₈ solution. The scale is removed and a bare, white surface is achieved without electricity and only by the oxidizing aftertreatment with salts of trivalent iron or with persulfates. However, the method mentioned can only be carried out with ferritic stainless steel, since austenitic stainless steels also contain chromium, but because of the additional alloy element nickel, the scale is constructed in a completely different way and cannot be removed solely by the pickling method described.
Die Aufgabe der Erfindung ist daher ein Verfahren der eingangs erwähnten Art, bei welchem unter Beibehaltung oder sogar Steigerung des guten bislang erzielten Beizeffektes gleichzeitig eine Verkürzung der Behandlungsdauer erreicht werden kann.The object of the invention is therefore a method of the type mentioned in the introduction, in which a reduction in the duration of treatment can be achieved while maintaining or even increasing the good pickling effect achieved to date.
Die Aufgabe wird erfindungsgemäß dadurch gelöst, daß der Beize mit Neutralelektrolyt eine Vorbehandlung mit Schwefelsäure vorangeht.The object is achieved in that the pickling with neutral electrolyte precedes a pretreatment with sulfuric acid.
Gemäß einem weiteren Merkmal der Erfindung erfolgt die Vorbehandlung mit Schwefelsäure bei einer Temperatur von 60 bis 95°C, vorzugsweise zwischen 75 und 85°C.According to a further feature of the invention, the pretreatment with sulfuric acid is carried out at a temperature of 60 to 95 ° C, preferably between 75 and 85 ° C.
Gemäß einem weiteren Merkmal der Erfindung beträgt die Konzentration der Schwefelsäure zwischen 200 und 500 g/l, vorzugsweise zwischen 300 und 400 g/l.According to a further feature of the invention, the concentration of sulfuric acid is between 200 and 500 g / l, preferably between 300 and 400 g / l.
Gemäß einem weiteren Merkmal der Erfindung beträgt die Vorbehandlung mit Schwefelsäure zwischen 5 und 30% der Gesamtbehandlungszeit, sowie die Beize in Neutralelektrolyt zwischen 25 und 50% der gesamten Behandlungszeit.According to a further feature of the invention, the pretreatment with sulfuric acid is between 5 and 30% of the total treatment time, and the pickling in neutral electrolyte is between 25 and 50% of the total treatment time.
Der Vorteil des erfindungsgemäßen dreistufigen Beizverfahrens liegt darin, daß es sowohl für austenitische (AISI 304 und 316) als auch für ferritische Edelstahl-Qualitäten (AISI 430) anwendbar ist und bei beiden Edelstahlqualitäten eine starke Verkürzung der Beizzeit eintritt.The advantage of the three-stage pickling process according to the invention is that it can be used both for austenitic (AISI 304 and 316) and for ferritic stainless steel grades (AISI 430) and the pickling time is greatly reduced for both stainless steel grades.
Durch die erfindungsgemäße kurze Vorbehandlung des Edelstahls mit vorzugsweise verdünnter Schwefelsäure vor dem Eintritt in den Neutralelektrolyt kann die Beizzeit im Neutralelektrolyt sowie in der anschließenden Mischsäure verkürzt werden, wodurch in den bestehenden Anlagen bei gleichem Platzbedarf eine wesentliche Leistungssteigerung erzielt wird. Andererseits können neu konzipierte Anlagen bei gleicher Leistung wie bestehende Anlagen weitaus geringer dimensioniert und daher wirtschaftlich günstiger und kostensparender ausgelegt werden.The short pretreatment of the stainless steel according to the invention with preferably dilute sulfuric acid before entering the neutral electrolyte can reduce the pickling time in the neutral electrolyte and in the subsequent mixed acid, as a result of which a substantial increase in performance is achieved in the existing systems with the same space requirement. On the other hand, newly designed systems with the same performance as existing systems can be dimensioned much smaller and therefore economically more economical and cost-saving.
Wie bei den herkömmlichen Beizverfahren kann auch im erfindungsgemäßen Verfahren der Beizeffekt durch Bürsten des gebeizten Materials zwischen den einzelnen Behandlungen verbessert werden.As with the conventional pickling processes, the pickling effect can also be improved in the process according to the invention by brushing the pickled material between the individual treatments.
Das Bürsten kann dabei entweder zwischen der Vorbehandlung mit Schwefelsäure und der Neutralelektrolytbeize, zwischen Neutralelektrolytbeize und der Nachbehandlung in Mischsäure oder bei beiden Gelegenheiten sowie in der Spülung nach der Behandlung mit Mischsäure erfolgen. Dieses Bürsten hat keinen Einfluß auf die Beizzeit, verringert aber den Säureverbrauch, da lose anhaftender Zunder entfernt wird.Brushing can take place either between the pretreatment with sulfuric acid and the neutral electrolyte stain, between neutral electrolyte stain and the aftertreatment in mixed acid or on both occasions as well as in the rinse after the treatment with mixed acid. This brushing has no effect on the pickling time, but reduces the acid consumption because loosely adhering scale is removed.
Die Erfindung soll nun anhand einiger nicht einschränkender Beispiele näher erläutert werden.The invention will now be explained in more detail by means of a few non-limiting examples.
Ein Edelstahl-Warmband der Qualität AISI 304, 3,1 mm dick, wurde vorerst in Schwefelsäure, mit einer Konzentration von 350g/l bei einer Temperatur von 85°C, und anschließend in Mischsäure mit einer Konzentration von 25g/l HF und 150 g/l HNO₃, bei einer Temperatur von 55°C, gebeizt, wobei die Beizzeit insgesamt 180 sec. und das Verhältnis der Beizzeiten 2 : 1 betrug. Bei Verwendung von Neutralelektrolyt, hier Na₂SO₄ mit einer Konzentration von 150 g/l, anstatt Schwefelsäure sowie anschließender Mischsäurenachbehandlung, mit denselben Parametern wie oben, konnte die Beizzeit auf 120 sec. verringert werden, wobei das Verhältnis der Behandlungszeiten nun 1 : 1 war. Die Polarisierung des Bandes wechselte von anodisch, mit einer Stromdichte von 10A/dm², auf kathodisch, mit 20A/dm², und anschließend wieder auf anodisch mit 10A/dm². Die Temperatur der Neutralelektrolyten betrug 80°C. Nach Einbau einer Schwefelsäurevorbehandlungsstufe konnte die anschließende Beizdauer im Neutralelektrolyt verkürzt und die Gesamtbeizzeit auf insgesamt 90 sec. verringert werden, wobei das Verhältnis der Beizzeiten in den einzelnen Stufen nunmehr 1 : 2 : 4 betrug. Die Konzentrationen und Temperaturen entsprachen auch beim erfindungsgemäßen Verfahren den oben angeführten Werten.A stainless steel hot strip of quality AISI 304, 3.1 mm thick, was initially in sulfuric acid, with a concentration of 350g / l a temperature of 85 ° C, and then in mixed acid with a concentration of 25g / l HF and 150 g / l HNO₃, at a temperature of 55 ° C, pickling, the pickling time a total of 180 sec. and the ratio of pickling times 2: 1 was. When using neutral electrolyte, here Na₂SO₄ with a concentration of 150 g / l, instead of sulfuric acid and subsequent mixed acid aftertreatment with the same parameters as above, the pickling time could be reduced to 120 seconds, the ratio of the treatment times now being 1: 1. The polarization of the band changed from anodic, with a current density of 10A / dm², to cathodic, with 20A / dm², and then back to anodic with 10A / dm². The temperature of the neutral electrolytes was 80 ° C. After installing a sulfuric acid pretreatment stage, the subsequent pickling time in the neutral electrolyte could be shortened and the total pickling time reduced to a total of 90 seconds, the ratio of the pickling times in the individual steps now being 1: 2: 4. The concentrations and temperatures also corresponded to the values given above in the method according to the invention.
Ein Edelstahl-Warmband der Qualität AISI 316 L, 6 mm stark, wurde den gleichen drei Beizverfahren wie im Ausführungsbeispiel 1, mit den gleichen Verfahrensparametern, unterworfen. Hier konnte die Beizzeit von 360 sec. in Schwefelsäure und Mischsäure auf 240 sec. in Neutralelektrolyt und Mischsäure sowie weiters auf 140 sec. bei Vorbehandlung mit Schwefelsäurebeize mit Neutralelektrolyt und Nachbehandlung mit Mischsäure verkürzt werden.A stainless steel hot strip of quality AISI 316 L, 6 mm thick, was subjected to the same three pickling processes as in exemplary embodiment 1, with the same process parameters. Here the pickling time could be reduced from 360 seconds in sulfuric acid and mixed acid to 240 seconds in neutral electrolyte and mixed acid and further to 140 seconds in the case of pretreatment with sulfuric acid stain with neutral electrolyte and aftertreatment with mixed acid.
Bei einem ferritischen Warmband der Qualität AISI 430 betrugen die Beizzeiten für die ersten beiden Beizverfahren entsprechend den zuvor genannten Ausführungsbeispielen jeweils etwa 270 sec. Bei zusätzlicher Vorbehandlung mit Schwefelsäure vor der Neutralelektrolytbeize konnte eine Verringerung der Behandlungszeit auf 210 sec. erzielt werden.In the case of a ferritic hot-rolled strip of quality AISI 430, the pickling times for the first two pickling processes, in accordance with the above-mentioned exemplary embodiments, were each about 270 seconds. With additional pretreatment with sulfuric acid before the neutral electrolyte pickling, the treatment time could be reduced to 210 seconds.
Beim Vergleich der Proben aus den drei angewendeten Beizverfahren konnte festgestellt werden, daß die Oberflächen optisch den gleichen Reflexionsgrad aufwiesen, einwandfrei gebeizt und zunderfrei waren.When comparing the samples from the three pickling processes used, it was found that the surfaces had the same reflectance optically, were pickled properly and were free of scale.
Claims (5)
- Pickling process for high-grade steel, preferably hot-rolled high-grade steel strip, where the high-grade steel is subjected to electrolytic pickling with neutral electrolyte and a secondary treatment with mixed acid, nitric acid or a mixture of iron fluoride (FeF3) and hydrofluoric acid, which can be applied with or without electric current, characterized by pretreatment with sulfuric acid prior to the pickling with neutral electrolyte.
- Process according to claim 1, characterized by the pretreatment with sulfuric acid taking place at a temperature of 60 to 95 ° C, preferably between 75 and 85 ° C.
- Process according to claim 1, characterized by the sulfuric acid concentration being 200 to 500 grams per litre, preferably 300 to 400 grams per litre.
- Process according to claim 1, characterized by the strip being brushed after pretreatment with sulfuric acid and before pickling with neutral electrolyte and/or after pickling with neutral electrolyte and before secondary treatment with acids.
- Process according to claim 1, characterized by the fact that the pretreatment with sulfuric acid amounts to between 5% and 30% of the total treatment time, and the pickling with neutral electrolyte to between 25% and 50% of the total treatment time.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AT0157990A AT395601B (en) | 1990-07-27 | 1990-07-27 | METHOD FOR STAINLESSING STAINLESS STEEL |
| AT1579/90 | 1990-07-27 |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| EP0471662A2 EP0471662A2 (en) | 1992-02-19 |
| EP0471662A3 EP0471662A3 (en) | 1992-05-20 |
| EP0471662B1 true EP0471662B1 (en) | 1995-09-13 |
Family
ID=3516469
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP91890156A Expired - Lifetime EP0471662B1 (en) | 1990-07-27 | 1991-07-17 | Process for pickling stainless steel |
Country Status (10)
| Country | Link |
|---|---|
| US (1) | US5130000A (en) |
| EP (1) | EP0471662B1 (en) |
| JP (1) | JP2721053B2 (en) |
| KR (1) | KR100218840B1 (en) |
| AT (2) | AT395601B (en) |
| DE (1) | DE59106467D1 (en) |
| ES (1) | ES2079634T3 (en) |
| RU (1) | RU2085616C1 (en) |
| UA (1) | UA25894A1 (en) |
| ZA (1) | ZA915877B (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AT402737B (en) * | 1992-04-29 | 1997-08-25 | Andritz Patentverwaltung | Method for discontinuous pickling of metallic plates, in particular made of stainless steel |
| US6096183A (en) * | 1997-12-05 | 2000-08-01 | Ak Steel Corporation | Method of reducing defects caused by conductor roll surface anomalies using high volume bottom sprays |
| KR20080048148A (en) * | 2006-11-28 | 2008-06-02 | 주식회사 한울로보틱스 | System protecting touch-screen of robot |
| ES2605452T3 (en) * | 2011-09-26 | 2017-03-14 | Ak Steel Properties, Inc. | Pickling stainless steel in an oxidizing electrolytic acid bath |
| CN104593857A (en) * | 2014-12-16 | 2015-05-06 | 张家港浦项不锈钢有限公司 | Ferrite stainless steel processing method |
| RU2578623C1 (en) * | 2014-12-30 | 2016-03-27 | Публичное акционерное общество "Ашинский металлургический завод" | Electrolytic method for removing scales from belt of rolled metal |
| CN109267142A (en) * | 2018-09-26 | 2019-01-25 | 中国民航大学 | A kind of PH stainless steel room temperature electrolytic pickling method |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5550468A (en) * | 1978-10-11 | 1980-04-12 | Kawasaki Steel Corp | Pickling method for cr base stainless steel |
| US4415415A (en) * | 1982-11-24 | 1983-11-15 | Allegheny Ludlum Steel Corporation | Method of controlling oxide scale formation and descaling thereof from metal articles |
| JPS61266588A (en) * | 1985-05-22 | 1986-11-26 | Nisshin Steel Co Ltd | Method for descaling stainless steel |
| AT387406B (en) * | 1987-05-07 | 1989-01-25 | Andritz Ag Maschf | METHOD FOR ELECTROLYTICALLY STICKING CHROME-CONTAINING STAINLESS STEEL |
| JPS63295011A (en) * | 1987-05-26 | 1988-12-01 | Nisshin Steel Co Ltd | Descaling device for stainless steel |
| JPH0759759B2 (en) * | 1988-10-29 | 1995-06-28 | 株式会社日立製作所 | Method and apparatus for descaling annealed stainless steel strip |
-
1990
- 1990-07-27 AT AT0157990A patent/AT395601B/en not_active IP Right Cessation
-
1991
- 1991-07-17 EP EP91890156A patent/EP0471662B1/en not_active Expired - Lifetime
- 1991-07-17 ES ES91890156T patent/ES2079634T3/en not_active Expired - Lifetime
- 1991-07-17 DE DE59106467T patent/DE59106467D1/en not_active Expired - Fee Related
- 1991-07-17 AT AT91890156T patent/ATE127866T1/en not_active IP Right Cessation
- 1991-07-18 KR KR1019910012248A patent/KR100218840B1/en not_active IP Right Cessation
- 1991-07-19 US US07/732,817 patent/US5130000A/en not_active Expired - Fee Related
- 1991-07-24 JP JP3184508A patent/JP2721053B2/en not_active Expired - Lifetime
- 1991-07-26 UA UA5001185A patent/UA25894A1/en unknown
- 1991-07-26 RU SU915001185A patent/RU2085616C1/en active
- 1991-07-26 ZA ZA915877A patent/ZA915877B/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| EP0471662A2 (en) | 1992-02-19 |
| ZA915877B (en) | 1992-04-29 |
| JPH04232299A (en) | 1992-08-20 |
| ATA157990A (en) | 1992-06-15 |
| UA25894A1 (en) | 1999-02-26 |
| ATE127866T1 (en) | 1995-09-15 |
| RU2085616C1 (en) | 1997-07-27 |
| JP2721053B2 (en) | 1998-03-04 |
| AT395601B (en) | 1993-02-25 |
| DE59106467D1 (en) | 1995-10-19 |
| KR100218840B1 (en) | 1999-09-01 |
| ES2079634T3 (en) | 1996-01-16 |
| EP0471662A3 (en) | 1992-05-20 |
| US5130000A (en) | 1992-07-14 |
| KR920002826A (en) | 1992-02-28 |
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